Completely separate MediaSource & DrmSession EventDispatchers

PiperOrigin-RevId: 319989989

Completely separate MediaSource & DrmSession EventDispatchers
PiperOrigin-RevId: 319989989
fa594489 · ibaker · kim-vde · 4c75339e · fa594489 · fa594489
Commit fa594489 authored Jul 07, 2020 by ibaker Committed by kim-vde Jul 08, 2020
Showing with 869 additions and 859 deletions
library/common/src/main/java/com/google/android/exoplayer2/util/Consumer.java
library/core/src/main/java/com/google/android/exoplayer2/MediaSourceList.java
library/core/src/main/java/com/google/android/exoplayer2/drm/DefaultDrmSession.java
library/core/src/main/java/com/google/android/exoplayer2/drm/DefaultDrmSessionManager.java
library/core/src/main/java/com/google/android/exoplayer2/drm/DrmSession.java
library/core/src/main/java/com/google/android/exoplayer2/drm/DrmSessionEventListener.java
library/core/src/main/java/com/google/android/exoplayer2/drm/DrmSessionManager.java
library/core/src/main/java/com/google/android/exoplayer2/drm/ErrorStateDrmSession.java
library/core/src/main/java/com/google/android/exoplayer2/drm/OfflineLicenseHelper.java
library/core/src/main/java/com/google/android/exoplayer2/source/BaseMediaSource.java
library/core/src/main/java/com/google/android/exoplayer2/source/CompositeMediaSource.java
library/core/src/main/java/com/google/android/exoplayer2/source/MediaSourceEventListener.java
library/core/src/main/java/com/google/android/exoplayer2/source/ProgressiveMediaPeriod.java
library/core/src/main/java/com/google/android/exoplayer2/source/ProgressiveMediaSource.java
library/core/src/main/java/com/google/android/exoplayer2/source/SampleQueue.java
library/core/src/main/java/com/google/android/exoplayer2/source/chunk/ChunkSampleStream.java
library/core/src/main/java/com/google/android/exoplayer2/util/MediaSourceEventDispatcher.java
library/core/src/test/java/com/google/android/exoplayer2/ExoPlayerTest.java
library/core/src/test/java/com/google/android/exoplayer2/audio/DecoderAudioRendererTest.java
library/core/src/test/java/com/google/android/exoplayer2/audio/MediaCodecAudioRendererTest.java
--- a/library/common/src/main/java/com/google/android/exoplayer2/util/Consumer.java
+++ b/library/common/src/main/java/com/google/android/exoplayer2/util/Consumer.java
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.util;
+/**
+ * Represents an operation that accepts a single input argument and returns no result. Unlike most
+ * other functional interfaces, Consumer is expected to operate via side-effects.
+ */
+public interface Consumer<T> {
+  /** Performs this operation on the given argument. */
+  void accept(T t);
+}
--- a/library/core/src/main/java/com/google/android/exoplayer2/MediaSourceList.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/MediaSourceList.java
@@ -70,7 +70,8 @@ import java.util.Set;
  private final IdentityHashMap<MediaPeriod, MediaSourceHolder> mediaSourceByMediaPeriod;
  private final Map<Object, MediaSourceHolder> mediaSourceByUid;
  private final MediaSourceListInfoRefreshListener mediaSourceListInfoListener;
-  private final MediaSourceEventListener.EventDispatcher eventDispatcher;
+  private final MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher;
+  private final DrmSessionEventListener.EventDispatcher drmEventDispatcher;
  private final HashMap<MediaSourceList.MediaSourceHolder, MediaSourceAndListener> childSources;
  private final Set<MediaSourceHolder> enabledMediaSourceHolders;
@@ -98,14 +99,13 @@ import java.util.Set;
    mediaSourceByMediaPeriod = new IdentityHashMap<>();
    mediaSourceByUid = new HashMap<>();
    mediaSourceHolders = new ArrayList<>();
-    eventDispatcher = new MediaSourceEventListener.EventDispatcher();
+    mediaSourceEventDispatcher = new MediaSourceEventListener.EventDispatcher();
+    drmEventDispatcher = new DrmSessionEventListener.EventDispatcher();
    childSources = new HashMap<>();
    enabledMediaSourceHolders = new HashSet<>();
    if (analyticsCollector != null) {
-      eventDispatcher.addEventListener(
+      mediaSourceEventDispatcher.addEventListener(analyticsCollectorHandler, analyticsCollector);
-          analyticsCollectorHandler, analyticsCollector, MediaSourceEventListener.class);
+      drmEventDispatcher.addEventListener(analyticsCollectorHandler, analyticsCollector);
-      eventDispatcher.addEventListener(
-          analyticsCollectorHandler, analyticsCollector, DrmSessionEventListener.class);
    }
  }
@@ -523,10 +523,12 @@ import java.util.Set;
      implements MediaSourceEventListener, DrmSessionEventListener {
    private final MediaSourceList.MediaSourceHolder id;
-    private EventDispatcher eventDispatcher;
+    private MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher;
+    private DrmSessionEventListener.EventDispatcher drmEventDispatcher;
    public ForwardingEventListener(MediaSourceList.MediaSourceHolder id) {
-      eventDispatcher = MediaSourceList.this.eventDispatcher;
+      mediaSourceEventDispatcher = MediaSourceList.this.mediaSourceEventDispatcher;
+      drmEventDispatcher = MediaSourceList.this.drmEventDispatcher;
      this.id = id;
    }
@@ -535,14 +537,14 @@ import java.util.Set;
    @Override
    public void onMediaPeriodCreated(int windowIndex, MediaSource.MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.mediaPeriodCreated();
+        mediaSourceEventDispatcher.mediaPeriodCreated();
      }
    }
    @Override
    public void onMediaPeriodReleased(int windowIndex, MediaSource.MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.mediaPeriodReleased();
+        mediaSourceEventDispatcher.mediaPeriodReleased();
      }
    }
@@ -553,7 +555,7 @@ import java.util.Set;
        LoadEventInfo loadEventData,
        MediaLoadData mediaLoadData) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.loadStarted(loadEventData, mediaLoadData);
+        mediaSourceEventDispatcher.loadStarted(loadEventData, mediaLoadData);
      }
    }
@@ -564,7 +566,7 @@ import java.util.Set;
        LoadEventInfo loadEventData,
        MediaLoadData mediaLoadData) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.loadCompleted(loadEventData, mediaLoadData);
+        mediaSourceEventDispatcher.loadCompleted(loadEventData, mediaLoadData);
      }
    }
@@ -575,7 +577,7 @@ import java.util.Set;
        LoadEventInfo loadEventData,
        MediaLoadData mediaLoadData) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.loadCanceled(loadEventData, mediaLoadData);
+        mediaSourceEventDispatcher.loadCanceled(loadEventData, mediaLoadData);
      }
    }
@@ -588,14 +590,14 @@ import java.util.Set;
        IOException error,
        boolean wasCanceled) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.loadError(loadEventData, mediaLoadData, error, wasCanceled);
+        mediaSourceEventDispatcher.loadError(loadEventData, mediaLoadData, error, wasCanceled);
      }
    }
    @Override
    public void onReadingStarted(int windowIndex, MediaSource.MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.readingStarted();
+        mediaSourceEventDispatcher.readingStarted();
      }
    }
@@ -605,7 +607,7 @@ import java.util.Set;
        @Nullable MediaSource.MediaPeriodId mediaPeriodId,
        MediaLoadData mediaLoadData) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.upstreamDiscarded(mediaLoadData);
+        mediaSourceEventDispatcher.upstreamDiscarded(mediaLoadData);
      }
    }
@@ -615,7 +617,7 @@ import java.util.Set;
        @Nullable MediaSource.MediaPeriodId mediaPeriodId,
        MediaLoadData mediaLoadData) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.downstreamFormatChanged(mediaLoadData);
+        mediaSourceEventDispatcher.downstreamFormatChanged(mediaLoadData);
      }
    }
@@ -625,8 +627,7 @@ import java.util.Set;
    public void onDrmSessionAcquired(
        int windowIndex, @Nullable MediaSource.MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.dispatch(
+        drmEventDispatcher.drmSessionAcquired();
-            DrmSessionEventListener::onDrmSessionAcquired, DrmSessionEventListener.class);
      }
    }
@@ -634,8 +635,7 @@ import java.util.Set;
    public void onDrmKeysLoaded(
        int windowIndex, @Nullable MediaSource.MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.dispatch(
+        drmEventDispatcher.drmKeysLoaded();
-            DrmSessionEventListener::onDrmKeysLoaded, DrmSessionEventListener.class);
      }
    }
@@ -643,10 +643,7 @@ import java.util.Set;
    public void onDrmSessionManagerError(
        int windowIndex, @Nullable MediaSource.MediaPeriodId mediaPeriodId, Exception error) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.dispatch(
+        drmEventDispatcher.drmSessionManagerError(error);
-            (listener, innerWindowIndex, innerMediaPeriodId) ->
-                listener.onDrmSessionManagerError(innerWindowIndex, innerMediaPeriodId, error),
-            DrmSessionEventListener.class);
      }
    }
@@ -654,8 +651,7 @@ import java.util.Set;
    public void onDrmKeysRestored(
        int windowIndex, @Nullable MediaSource.MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.dispatch(
+        drmEventDispatcher.drmKeysRestored();
-            DrmSessionEventListener::onDrmKeysRestored, DrmSessionEventListener.class);
      }
    }
@@ -663,8 +659,7 @@ import java.util.Set;
    public void onDrmKeysRemoved(
        int windowIndex, @Nullable MediaSource.MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.dispatch(
+        drmEventDispatcher.drmKeysRemoved();
-            DrmSessionEventListener::onDrmKeysRemoved, DrmSessionEventListener.class);
      }
    }
@@ -672,8 +667,7 @@ import java.util.Set;
    public void onDrmSessionReleased(
        int windowIndex, @Nullable MediaSource.MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.dispatch(
+        drmEventDispatcher.drmSessionReleased();
-            DrmSessionEventListener::onDrmSessionReleased, DrmSessionEventListener.class);
      }
    }
@@ -689,12 +683,17 @@ import java.util.Set;
        }
      }
      int windowIndex = getWindowIndexForChildWindowIndex(id, childWindowIndex);
-      if (eventDispatcher.windowIndex != windowIndex
+      if (mediaSourceEventDispatcher.windowIndex != windowIndex
-          || !Util.areEqual(eventDispatcher.mediaPeriodId, mediaPeriodId)) {
+          || !Util.areEqual(mediaSourceEventDispatcher.mediaPeriodId, mediaPeriodId)) {
-        eventDispatcher =
+        mediaSourceEventDispatcher =
-            MediaSourceList.this.eventDispatcher.withParameters(
+            MediaSourceList.this.mediaSourceEventDispatcher.withParameters(
                windowIndex, mediaPeriodId, /* mediaTimeOffsetMs= */ 0L);
      }
+      if (drmEventDispatcher.windowIndex != windowIndex
+          || !Util.areEqual(drmEventDispatcher.mediaPeriodId, mediaPeriodId)) {
+        drmEventDispatcher =
+            MediaSourceList.this.drmEventDispatcher.withParameters(windowIndex, mediaPeriodId);
+      }
      return true;
    }
  }

--- a/library/core/src/main/java/com/google/android/exoplayer2/drm/DefaultDrmSession.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/drm/DefaultDrmSession.java
@@ -34,9 +34,9 @@ import com.google.android.exoplayer2.source.MediaLoadData;
 import com.google.android.exoplayer2.upstream.LoadErrorHandlingPolicy;
 import com.google.android.exoplayer2.upstream.LoadErrorHandlingPolicy.LoadErrorInfo;
 import com.google.android.exoplayer2.util.Assertions;
+import com.google.android.exoplayer2.util.Consumer;
 import com.google.android.exoplayer2.util.CopyOnWriteMultiset;
 import com.google.android.exoplayer2.util.Log;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import com.google.android.exoplayer2.util.Util;
 import java.io.IOException;
 import java.util.Arrays;
@@ -123,7 +123,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
  private final boolean playClearSamplesWithoutKeys;
  private final boolean isPlaceholderSession;
  private final HashMap<String, String> keyRequestParameters;
-  private final CopyOnWriteMultiset<MediaSourceEventDispatcher> eventDispatchers;
+  private final CopyOnWriteMultiset<DrmSessionEventListener.EventDispatcher> eventDispatchers;
  private final LoadErrorHandlingPolicy loadErrorHandlingPolicy;
  /* package */ final MediaDrmCallback callback;
@@ -271,7 +271,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
  }
  @Override
-  public void acquire(@Nullable MediaSourceEventDispatcher eventDispatcher) {
+  public void acquire(@Nullable DrmSessionEventListener.EventDispatcher eventDispatcher) {
    Assertions.checkState(referenceCount >= 0);
    if (eventDispatcher != null) {
      eventDispatchers.add(eventDispatcher);
@@ -288,14 +288,13 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
      // If the session is already open then send the acquire event only to the provided dispatcher.
      // TODO: Add a parameter to onDrmSessionAcquired to indicate whether the session is being
      // re-used or not.
-      eventDispatcher.dispatch(
+      eventDispatcher.drmSessionAcquired();
-          DrmSessionEventListener::onDrmSessionAcquired, DrmSessionEventListener.class);
    }
    referenceCountListener.onReferenceCountIncremented(this, referenceCount);
  }
  @Override
-  public void release(@Nullable MediaSourceEventDispatcher eventDispatcher) {
+  public void release(@Nullable DrmSessionEventListener.EventDispatcher eventDispatcher) {
    if (--referenceCount == 0) {
      // Assigning null to various non-null variables for clean-up.
      state = STATE_RELEASED;
@@ -312,14 +311,13 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
        mediaDrm.closeSession(sessionId);
        sessionId = null;
      }
-      dispatchEvent(DrmSessionEventListener::onDrmSessionReleased);
+      dispatchEvent(DrmSessionEventListener.EventDispatcher::drmSessionReleased);
    }
    if (eventDispatcher != null) {
      if (isOpen()) {
        // If the session is still open then send the release event only to the provided dispatcher
        // before removing it.
-        eventDispatcher.dispatch(
+        eventDispatcher.drmSessionReleased();
-            DrmSessionEventListener::onDrmSessionReleased, DrmSessionEventListener.class);
      }
      eventDispatchers.remove(eventDispatcher);
    }
@@ -345,7 +343,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
    try {
      sessionId = mediaDrm.openSession();
      mediaCrypto = mediaDrm.createMediaCrypto(sessionId);
-      dispatchEvent(DrmSessionEventListener::onDrmSessionAcquired);
+      dispatchEvent(DrmSessionEventListener.EventDispatcher::drmSessionAcquired);
      state = STATE_OPENED;
      Assertions.checkNotNull(sessionId);
      return true;
@@ -409,7 +407,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
            onError(new KeysExpiredException());
          } else {
            state = STATE_OPENED_WITH_KEYS;
-            dispatchEvent(DrmSessionEventListener::onDrmKeysRestored);
+            dispatchEvent(DrmSessionEventListener.EventDispatcher::drmKeysRestored);
          }
        }
        break;
@@ -479,7 +477,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
      byte[] responseData = (byte[]) response;
      if (mode == DefaultDrmSessionManager.MODE_RELEASE) {
        mediaDrm.provideKeyResponse(Util.castNonNull(offlineLicenseKeySetId), responseData);
-        dispatchEvent(DrmSessionEventListener::onDrmKeysRemoved);
+        dispatchEvent(DrmSessionEventListener.EventDispatcher::drmKeysRemoved);
      } else {
        byte[] keySetId = mediaDrm.provideKeyResponse(sessionId, responseData);
        if ((mode == DefaultDrmSessionManager.MODE_DOWNLOAD
@@ -490,7 +488,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
          offlineLicenseKeySetId = keySetId;
        }
        state = STATE_OPENED_WITH_KEYS;
-        dispatchEvent(DrmSessionEventListener::onDrmKeysLoaded);
+        dispatchEvent(DrmSessionEventListener.EventDispatcher::drmKeysLoaded);
      }
    } catch (Exception e) {
      onKeysError(e);
@@ -514,9 +512,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
  private void onError(final Exception e) {
    lastException = new DrmSessionException(e);
-    dispatchEvent(
+    dispatchEvent(eventDispatcher -> eventDispatcher.drmSessionManagerError(e));
-        (listener, windowIndex, mediaPeriodId) ->
-            listener.onDrmSessionManagerError(windowIndex, mediaPeriodId, e));
    if (state != STATE_OPENED_WITH_KEYS) {
      state = STATE_ERROR;
    }
@@ -528,10 +524,9 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
    return state == STATE_OPENED || state == STATE_OPENED_WITH_KEYS;
  }
-  private void dispatchEvent(
+  private void dispatchEvent(Consumer<DrmSessionEventListener.EventDispatcher> event) {
-      MediaSourceEventDispatcher.EventWithPeriodId<DrmSessionEventListener> event) {
+    for (DrmSessionEventListener.EventDispatcher eventDispatcher : eventDispatchers.elementSet()) {
-    for (MediaSourceEventDispatcher eventDispatcher : eventDispatchers.elementSet()) {
+      event.accept(eventDispatcher);
-      eventDispatcher.dispatch(event, DrmSessionEventListener.class);
    }
  }

--- a/library/core/src/main/java/com/google/android/exoplayer2/drm/DefaultDrmSessionManager.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/drm/DefaultDrmSessionManager.java
@@ -32,7 +32,6 @@ import com.google.android.exoplayer2.upstream.DefaultLoadErrorHandlingPolicy;
 import com.google.android.exoplayer2.upstream.LoadErrorHandlingPolicy;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Log;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import com.google.android.exoplayer2.util.Util;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Sets;
@@ -406,8 +405,8 @@ public class DefaultDrmSessionManager implements DrmSessionManager {
  /**
   * Sets the mode, which determines the role of sessions acquired from the instance. This must be
-   * called before {@link #acquireSession(Looper, MediaSourceEventDispatcher, DrmInitData)} or
+   * called before {@link #acquireSession(Looper, DrmSessionEventListener.EventDispatcher,
-   * {@link #acquirePlaceholderSession} is called.
+   * DrmInitData)} or {@link #acquirePlaceholderSession} is called.
   *
   * <p>By default, the mode is {@link #MODE_PLAYBACK} and a streaming license is requested when
   * required.
@@ -527,7 +526,7 @@ public class DefaultDrmSessionManager implements DrmSessionManager {
  @Override
  public DrmSession acquireSession(
      Looper playbackLooper,
-      @Nullable MediaSourceEventDispatcher eventDispatcher,
+      @Nullable DrmSessionEventListener.EventDispatcher eventDispatcher,
      DrmInitData drmInitData) {
    initPlaybackLooper(playbackLooper);
    maybeCreateMediaDrmHandler(playbackLooper);
@@ -538,10 +537,7 @@ public class DefaultDrmSessionManager implements DrmSessionManager {
      if (schemeDatas.isEmpty()) {
        final MissingSchemeDataException error = new MissingSchemeDataException(uuid);
        if (eventDispatcher != null) {
-          eventDispatcher.dispatch(
+          eventDispatcher.drmSessionManagerError(error);
-              (listener, windowIndex, mediaPeriodId) ->
-                  listener.onDrmSessionManagerError(windowIndex, mediaPeriodId, error),
-              DrmSessionEventListener.class);
        }
        return new ErrorStateDrmSession(new DrmSessionException(error));
      }
@@ -605,7 +601,7 @@ public class DefaultDrmSessionManager implements DrmSessionManager {
  private DefaultDrmSession createAndAcquireSessionWithRetry(
      @Nullable List<SchemeData> schemeDatas,
      boolean isPlaceholderSession,
-      @Nullable MediaSourceEventDispatcher eventDispatcher) {
+      @Nullable DrmSessionEventListener.EventDispatcher eventDispatcher) {
    DefaultDrmSession session =
        createAndAcquireSession(schemeDatas, isPlaceholderSession, eventDispatcher);
    if (session.getState() == DrmSession.STATE_ERROR
@@ -644,7 +640,7 @@ public class DefaultDrmSessionManager implements DrmSessionManager {
  private DefaultDrmSession createAndAcquireSession(
      @Nullable List<SchemeData> schemeDatas,
      boolean isPlaceholderSession,
-      @Nullable MediaSourceEventDispatcher eventDispatcher) {
+      @Nullable DrmSessionEventListener.EventDispatcher eventDispatcher) {
    Assertions.checkNotNull(exoMediaDrm);
    // Placeholder sessions should always play clear samples without keys.
    boolean playClearSamplesWithoutKeys = this.playClearSamplesWithoutKeys | isPlaceholderSession;

--- a/library/core/src/main/java/com/google/android/exoplayer2/drm/DrmSession.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/drm/DrmSession.java
@@ -18,7 +18,6 @@ package com.google.android.exoplayer2.drm;
 import android.media.MediaDrm;
 import androidx.annotation.IntDef;
 import androidx.annotation.Nullable;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import java.io.IOException;
 import java.lang.annotation.Documented;
 import java.lang.annotation.Retention;
@@ -31,10 +30,10 @@ public interface DrmSession {
  /**
   * Acquires {@code newSession} then releases {@code previousSession}.
   *
-   * <p>Invokes {@code newSession's} {@link #acquire(MediaSourceEventDispatcher)} and {@code
+   * <p>Invokes {@code newSession's} {@link #acquire(DrmSessionEventListener.EventDispatcher)} and
-   * previousSession's} {@link #release(MediaSourceEventDispatcher)} in that order (passing {@code
+   * {@code previousSession's} {@link #release(DrmSessionEventListener.EventDispatcher)} in that
-   * eventDispatcher = null}). Null arguments are ignored. Does nothing if {@code previousSession}
+   * order (passing {@code eventDispatcher = null}). Null arguments are ignored. Does nothing if
-   * and {@code newSession} are the same session.
+   * {@code previousSession} and {@code newSession} are the same session.
   */
  static void replaceSession(
      @Nullable DrmSession previousSession, @Nullable DrmSession newSession) {
@@ -134,20 +133,21 @@ public interface DrmSession {
  /**
   * Increments the reference count. When the caller no longer needs to use the instance, it must
-   * call {@link #release(MediaSourceEventDispatcher)} to decrement the reference count.
+   * call {@link #release(DrmSessionEventListener.EventDispatcher)} to decrement the reference
+   * count.
   *
-   * @param eventDispatcher The {@link MediaSourceEventDispatcher} used to route DRM-related events
+   * @param eventDispatcher The {@link DrmSessionEventListener.EventDispatcher} used to route
-   *     dispatched from this session, or null if no event handling is needed.
+   *     DRM-related events dispatched from this session, or null if no event handling is needed.
   */
-  void acquire(@Nullable MediaSourceEventDispatcher eventDispatcher);
+  void acquire(@Nullable DrmSessionEventListener.EventDispatcher eventDispatcher);
  /**
   * Decrements the reference count. If the reference count drops to 0 underlying resources are
   * released, and the instance cannot be re-used.
   *
-   * @param eventDispatcher The {@link MediaSourceEventDispatcher} to disconnect when the session is
+   * @param eventDispatcher The {@link DrmSessionEventListener.EventDispatcher} to disconnect when
-   *     released (the same instance (possibly null) that was passed by the caller to {@link
+   *     the session is released (the same instance (possibly null) that was passed by the caller to
-   *     #acquire(MediaSourceEventDispatcher)}).
+   *     {@link #acquire(DrmSessionEventListener.EventDispatcher)}).
   */
-  void release(@Nullable MediaSourceEventDispatcher eventDispatcher);
+  void release(@Nullable DrmSessionEventListener.EventDispatcher eventDispatcher);
 }
--- a/library/core/src/main/java/com/google/android/exoplayer2/drm/DrmSessionEventListener.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/drm/DrmSessionEventListener.java
@@ -15,9 +15,14 @@
 */
 package com.google.android.exoplayer2.drm;
+import android.os.Handler;
+import android.os.Looper;
+import androidx.annotation.CheckResult;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
+import com.google.android.exoplayer2.util.Assertions;
+import java.util.concurrent.CopyOnWriteArrayList;
 /** Listener of {@link DrmSessionManager} events. */
 public interface DrmSessionEventListener {
@@ -78,4 +83,148 @@ public interface DrmSessionEventListener {
   * @param mediaPeriodId The {@link MediaPeriodId} associated with the drm session.
   */
  default void onDrmSessionReleased(int windowIndex, @Nullable MediaPeriodId mediaPeriodId) {}
+  /** Dispatches events to {@link DrmSessionEventListener DrmSessionEventListeners}. */
+  class EventDispatcher {
+    /** The timeline window index reported with the events. */
+    public final int windowIndex;
+    /** The {@link MediaPeriodId} reported with the events. */
+    @Nullable public final MediaPeriodId mediaPeriodId;
+    private final CopyOnWriteArrayList<EventDispatcher.ListenerAndHandler> listenerAndHandlers;
+    /** Creates an event dispatcher. */
+    public EventDispatcher() {
+      this(
+          /* listenerAndHandlers= */ new CopyOnWriteArrayList<>(),
+          /* windowIndex= */ 0,
+          /* mediaPeriodId= */ null);
+    }
+    private EventDispatcher(
+        CopyOnWriteArrayList<EventDispatcher.ListenerAndHandler> listenerAndHandlers,
+        int windowIndex,
+        @Nullable MediaPeriodId mediaPeriodId) {
+      this.listenerAndHandlers = listenerAndHandlers;
+      this.windowIndex = windowIndex;
+      this.mediaPeriodId = mediaPeriodId;
+    }
+    /**
+     * Creates a view of the event dispatcher with the provided window index and media period id.
+     *
+     * @param windowIndex The timeline window index to be reported with the events.
+     * @param mediaPeriodId The {@link MediaPeriodId} to be reported with the events.
+     * @return A view of the event dispatcher with the pre-configured parameters.
+     */
+    @CheckResult
+    public EventDispatcher withParameters(int windowIndex, @Nullable MediaPeriodId mediaPeriodId) {
+      return new EventDispatcher(listenerAndHandlers, windowIndex, mediaPeriodId);
+    }
+    /**
+     * Adds a listener to the event dispatcher.
+     *
+     * @param handler A handler on the which listener events will be posted.
+     * @param eventListener The listener to be added.
+     */
+    public void addEventListener(Handler handler, DrmSessionEventListener eventListener) {
+      Assertions.checkNotNull(handler);
+      Assertions.checkNotNull(eventListener);
+      listenerAndHandlers.add(new ListenerAndHandler(handler, eventListener));
+    }
+    /**
+     * Removes a listener from the event dispatcher.
+     *
+     * @param eventListener The listener to be removed.
+     */
+    public void removeEventListener(DrmSessionEventListener eventListener) {
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
+        if (listenerAndHandler.listener == eventListener) {
+          listenerAndHandlers.remove(listenerAndHandler);
+        }
+      }
+    }
+    /** Dispatches {@link #onDrmSessionAcquired(int, MediaPeriodId)}. */
+    public void drmSessionAcquired() {
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
+        DrmSessionEventListener listener = listenerAndHandler.listener;
+        postOrRun(
+            listenerAndHandler.handler,
+            () -> listener.onDrmSessionAcquired(windowIndex, mediaPeriodId));
+      }
+    }
+    /** Dispatches {@link #onDrmKeysLoaded(int, MediaPeriodId)}. */
+    public void drmKeysLoaded() {
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
+        DrmSessionEventListener listener = listenerAndHandler.listener;
+        postOrRun(
+            listenerAndHandler.handler, () -> listener.onDrmKeysLoaded(windowIndex, mediaPeriodId));
+      }
+    }
+    /** Dispatches {@link #onDrmSessionManagerError(int, MediaPeriodId, Exception)}. */
+    public void drmSessionManagerError(Exception error) {
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
+        DrmSessionEventListener listener = listenerAndHandler.listener;
+        postOrRun(
+            listenerAndHandler.handler,
+            () -> listener.onDrmSessionManagerError(windowIndex, mediaPeriodId, error));
+      }
+    }
+    /** Dispatches {@link #onDrmKeysRestored(int, MediaPeriodId)}. */
+    public void drmKeysRestored() {
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
+        DrmSessionEventListener listener = listenerAndHandler.listener;
+        postOrRun(
+            listenerAndHandler.handler,
+            () -> listener.onDrmKeysRestored(windowIndex, mediaPeriodId));
+      }
+    }
+    /** Dispatches {@link #onDrmKeysRemoved(int, MediaPeriodId)}. */
+    public void drmKeysRemoved() {
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
+        DrmSessionEventListener listener = listenerAndHandler.listener;
+        postOrRun(
+            listenerAndHandler.handler,
+            () -> listener.onDrmKeysRemoved(windowIndex, mediaPeriodId));
+      }
+    }
+    /** Dispatches {@link #onDrmSessionReleased(int, MediaPeriodId)}. */
+    public void drmSessionReleased() {
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
+        DrmSessionEventListener listener = listenerAndHandler.listener;
+        postOrRun(
+            listenerAndHandler.handler,
+            () -> listener.onDrmSessionReleased(windowIndex, mediaPeriodId));
+      }
+    }
+    /** Dispatches {@link #onDrmSessionAcquired(int, MediaPeriodId)}. */
+    private static void postOrRun(Handler handler, Runnable runnable) {
+      if (handler.getLooper() == Looper.myLooper()) {
+        runnable.run();
+      } else {
+        handler.post(runnable);
+      }
+    }
+    private static final class ListenerAndHandler {
+      public Handler handler;
+      public DrmSessionEventListener listener;
+      public ListenerAndHandler(Handler handler, DrmSessionEventListener listener) {
+        this.handler = handler;
+        this.listener = listener;
+      }
+    }
+  }
 }
--- a/library/core/src/main/java/com/google/android/exoplayer2/drm/DrmSessionManager.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/drm/DrmSessionManager.java
@@ -19,7 +19,6 @@ import android.os.Looper;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.drm.DrmInitData.SchemeData;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 /** Manages a DRM session. */
 public interface DrmSessionManager {
@@ -41,7 +40,7 @@ public interface DrmSessionManager {
        @Override
        public DrmSession acquireSession(
            Looper playbackLooper,
-            @Nullable MediaSourceEventDispatcher eventDispatcher,
+            @Nullable DrmSessionEventListener.EventDispatcher eventDispatcher,
            DrmInitData drmInitData) {
          return new ErrorStateDrmSession(
              new DrmSession.DrmSessionException(
@@ -83,7 +82,7 @@ public interface DrmSessionManager {
  /**
   * Returns a {@link DrmSession} that does not execute key requests, with an incremented reference
   * count. When the caller no longer needs to use the instance, it must call {@link
-   * DrmSession#release(MediaSourceEventDispatcher)} to decrement the reference count.
+   * DrmSession#release(DrmSessionEventListener.EventDispatcher)} to decrement the reference count.
   *
   * <p>Placeholder {@link DrmSession DrmSessions} may be used to configure secure decoders for
   * playback of clear content periods. This can reduce the cost of transitioning between clear and
@@ -103,18 +102,19 @@ public interface DrmSessionManager {
  /**
   * Returns a {@link DrmSession} for the specified {@link DrmInitData}, with an incremented
   * reference count. When the caller no longer needs to use the instance, it must call {@link
-   * DrmSession#release(MediaSourceEventDispatcher)} to decrement the reference count.
+   * DrmSession#release(DrmSessionEventListener.EventDispatcher)} to decrement the reference count.
   *
   * @param playbackLooper The looper associated with the media playback thread.
-   * @param eventDispatcher The {@link MediaSourceEventDispatcher} used to distribute events, and
+   * @param eventDispatcher The {@link DrmSessionEventListener.EventDispatcher} used to distribute
-   *     passed on to {@link DrmSession#acquire(MediaSourceEventDispatcher)}.
+   *     events, and passed on to {@link
+   *     DrmSession#acquire(DrmSessionEventListener.EventDispatcher)}.
   * @param drmInitData DRM initialization data. All contained {@link SchemeData}s must contain
   *     non-null {@link SchemeData#data}.
   * @return The DRM session.
   */
  DrmSession acquireSession(
      Looper playbackLooper,
-      @Nullable MediaSourceEventDispatcher eventDispatcher,
+      @Nullable DrmSessionEventListener.EventDispatcher eventDispatcher,
      DrmInitData drmInitData);
  /**

--- a/library/core/src/main/java/com/google/android/exoplayer2/drm/ErrorStateDrmSession.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/drm/ErrorStateDrmSession.java
@@ -17,7 +17,6 @@ package com.google.android.exoplayer2.drm;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.util.Assertions;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import java.util.Map;
 /** A {@link DrmSession} that's in a terminal error state. */
@@ -64,12 +63,12 @@ public final class ErrorStateDrmSession implements DrmSession {
  }
  @Override
-  public void acquire(@Nullable MediaSourceEventDispatcher eventDispatcher) {
+  public void acquire(@Nullable DrmSessionEventListener.EventDispatcher eventDispatcher) {
    // Do nothing.
  }
  @Override
-  public void release(@Nullable MediaSourceEventDispatcher eventDispatcher) {
+  public void release(@Nullable DrmSessionEventListener.EventDispatcher eventDispatcher) {
    // Do nothing.
  }
 }
--- a/library/core/src/main/java/com/google/android/exoplayer2/drm/OfflineLicenseHelper.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/drm/OfflineLicenseHelper.java
@@ -27,7 +27,6 @@ import com.google.android.exoplayer2.drm.DrmSession.DrmSessionException;
 import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
 import com.google.android.exoplayer2.upstream.HttpDataSource;
 import com.google.android.exoplayer2.util.Assertions;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import java.util.Map;
 import java.util.UUID;
@@ -40,7 +39,7 @@ public final class OfflineLicenseHelper {
  private final ConditionVariable conditionVariable;
  private final DefaultDrmSessionManager drmSessionManager;
  private final HandlerThread handlerThread;
-  private final MediaSourceEventDispatcher eventDispatcher;
+  private final DrmSessionEventListener.EventDispatcher eventDispatcher;
  /**
   * Instantiates a new instance which uses Widevine CDM. Call {@link #release()} when the instance
@@ -49,14 +48,14 @@ public final class OfflineLicenseHelper {
   * @param defaultLicenseUrl The default license URL. Used for key requests that do not specify
   *     their own license URL.
   * @param httpDataSourceFactory A factory from which to obtain {@link HttpDataSource} instances.
-   * @param eventDispatcher A {@link MediaSourceEventDispatcher} used to distribute DRM-related
+   * @param eventDispatcher A {@link DrmSessionEventListener.EventDispatcher} used to distribute
-   *     events.
+   *     DRM-related events.
   * @return A new instance which uses Widevine CDM.
   */
  public static OfflineLicenseHelper newWidevineInstance(
      String defaultLicenseUrl,
      HttpDataSource.Factory httpDataSourceFactory,
-      MediaSourceEventDispatcher eventDispatcher) {
+      DrmSessionEventListener.EventDispatcher eventDispatcher) {
    return newWidevineInstance(
        defaultLicenseUrl,
        /* forceDefaultLicenseUrl= */ false,
@@ -73,15 +72,15 @@ public final class OfflineLicenseHelper {
   * @param forceDefaultLicenseUrl Whether to use {@code defaultLicenseUrl} for key requests that
   *     include their own license URL.
   * @param httpDataSourceFactory A factory from which to obtain {@link HttpDataSource} instances.
-   * @param eventDispatcher A {@link MediaSourceEventDispatcher} used to distribute DRM-related
+   * @param eventDispatcher A {@link DrmSessionEventListener.EventDispatcher} used to distribute
-   *     events.
+   *     DRM-related events.
   * @return A new instance which uses Widevine CDM.
   */
  public static OfflineLicenseHelper newWidevineInstance(
      String defaultLicenseUrl,
      boolean forceDefaultLicenseUrl,
      HttpDataSource.Factory httpDataSourceFactory,
-      MediaSourceEventDispatcher eventDispatcher) {
+      DrmSessionEventListener.EventDispatcher eventDispatcher) {
    return newWidevineInstance(
        defaultLicenseUrl,
        forceDefaultLicenseUrl,
@@ -100,8 +99,8 @@ public final class OfflineLicenseHelper {
   *     include their own license URL.
   * @param optionalKeyRequestParameters An optional map of parameters to pass as the last argument
   *     to {@link MediaDrm#getKeyRequest}. May be null.
-   * @param eventDispatcher A {@link MediaSourceEventDispatcher} used to distribute DRM-related
+   * @param eventDispatcher A {@link DrmSessionEventListener.EventDispatcher} used to distribute
-   *     events.
+   *     DRM-related events.
   * @return A new instance which uses Widevine CDM.
   * @see DefaultDrmSessionManager.Builder
   */
@@ -110,7 +109,7 @@ public final class OfflineLicenseHelper {
      boolean forceDefaultLicenseUrl,
      HttpDataSource.Factory httpDataSourceFactory,
      @Nullable Map<String, String> optionalKeyRequestParameters,
-      MediaSourceEventDispatcher eventDispatcher) {
+      DrmSessionEventListener.EventDispatcher eventDispatcher) {
    return new OfflineLicenseHelper(
        new DefaultDrmSessionManager.Builder()
            .setKeyRequestParameters(optionalKeyRequestParameters)
@@ -122,7 +121,7 @@ public final class OfflineLicenseHelper {
  /**
   * @deprecated Use {@link #OfflineLicenseHelper(DefaultDrmSessionManager,
-   *     MediaSourceEventDispatcher)} instead.
+   *     DrmSessionEventListener.EventDispatcher)} instead.
   */
  @Deprecated
  public OfflineLicenseHelper(
@@ -130,7 +129,7 @@ public final class OfflineLicenseHelper {
      ExoMediaDrm.Provider mediaDrmProvider,
      MediaDrmCallback callback,
      @Nullable Map<String, String> optionalKeyRequestParameters,
-      MediaSourceEventDispatcher eventDispatcher) {
+      DrmSessionEventListener.EventDispatcher eventDispatcher) {
    this(
            new DefaultDrmSessionManager.Builder()
                .setUuidAndExoMediaDrmProvider(uuid, mediaDrmProvider)
@@ -143,12 +142,12 @@ public final class OfflineLicenseHelper {
   * Constructs an instance. Call {@link #release()} when the instance is no longer required.
   *
   * @param defaultDrmSessionManager The {@link DefaultDrmSessionManager} used to download licenses.
-   * @param eventDispatcher A {@link MediaSourceEventDispatcher} used to distribute DRM-related
+   * @param eventDispatcher A {@link DrmSessionEventListener.EventDispatcher} used to distribute
-   *     events.
+   *     DRM-related events.
   */
  public OfflineLicenseHelper(
      DefaultDrmSessionManager defaultDrmSessionManager,
-      MediaSourceEventDispatcher eventDispatcher) {
+      DrmSessionEventListener.EventDispatcher eventDispatcher) {
    this.drmSessionManager = defaultDrmSessionManager;
    this.eventDispatcher = eventDispatcher;
    handlerThread = new HandlerThread("ExoPlayer:OfflineLicenseHelper");
@@ -177,8 +176,7 @@ public final class OfflineLicenseHelper {
            conditionVariable.open();
          }
        };
-    eventDispatcher.addEventListener(
+    eventDispatcher.addEventListener(new Handler(handlerThread.getLooper()), eventListener);
-        new Handler(handlerThread.getLooper()), eventListener, DrmSessionEventListener.class);
  }
  /**

--- a/library/core/src/main/java/com/google/android/exoplayer2/source/BaseMediaSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/BaseMediaSource.java
@@ -22,7 +22,6 @@ import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.Assertions;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import java.util.ArrayList;
 import java.util.HashSet;
@@ -38,6 +37,7 @@ public abstract class BaseMediaSource implements MediaSource {
  private final ArrayList<MediaSourceCaller> mediaSourceCallers;
  private final HashSet<MediaSourceCaller> enabledMediaSourceCallers;
  private final MediaSourceEventListener.EventDispatcher eventDispatcher;
+  private final DrmSessionEventListener.EventDispatcher drmEventDispatcher;
  @Nullable private Looper looper;
  @Nullable private Timeline timeline;
@@ -46,6 +46,7 @@ public abstract class BaseMediaSource implements MediaSource {
    mediaSourceCallers = new ArrayList<>(/* initialCapacity= */ 1);
    enabledMediaSourceCallers = new HashSet<>(/* initialCapacity= */ 1);
    eventDispatcher = new MediaSourceEventListener.EventDispatcher();
+    drmEventDispatcher = new DrmSessionEventListener.EventDispatcher();
  }
  /**
@@ -127,6 +128,33 @@ public abstract class BaseMediaSource implements MediaSource {
    return eventDispatcher.withParameters(windowIndex, mediaPeriodId, mediaTimeOffsetMs);
  }
+  /**
+   * Returns a {@link DrmSessionEventListener.EventDispatcher} which dispatches all events to the
+   * registered listeners with the specified media period id.
+   *
+   * @param mediaPeriodId The {@link MediaPeriodId} to be reported with the events. May be null, if
+   *     the events do not belong to a specific media period.
+   * @return An event dispatcher with pre-configured media period id.
+   */
+  protected final DrmSessionEventListener.EventDispatcher createDrmEventDispatcher(
+      @Nullable MediaPeriodId mediaPeriodId) {
+    return drmEventDispatcher.withParameters(/* windowIndex= */ 0, mediaPeriodId);
+  }
+  /**
+   * Returns a {@link DrmSessionEventListener.EventDispatcher} which dispatches all events to the
+   * registered listeners with the specified window index and media period id.
+   *
+   * @param windowIndex The timeline window index to be reported with the events.
+   * @param mediaPeriodId The {@link MediaPeriodId} to be reported with the events. May be null, if
+   *     the events do not belong to a specific media period.
+   * @return An event dispatcher with pre-configured media period id and time offset.
+   */
+  protected final DrmSessionEventListener.EventDispatcher createDrmEventDispatcher(
+      int windowIndex, @Nullable MediaPeriodId mediaPeriodId) {
+    return drmEventDispatcher.withParameters(windowIndex, mediaPeriodId);
+  }
  /** Returns whether the source is enabled. */
  protected final boolean isEnabled() {
    return !enabledMediaSourceCallers.isEmpty();
@@ -134,44 +162,22 @@ public abstract class BaseMediaSource implements MediaSource {
  @Override
  public final void addEventListener(Handler handler, MediaSourceEventListener eventListener) {
-    addEventListenerInternal(handler, eventListener, MediaSourceEventListener.class);
+    eventDispatcher.addEventListener(handler, eventListener);
  }
  @Override
  public final void removeEventListener(MediaSourceEventListener eventListener) {
-    removeEventListenerInternal(eventListener, MediaSourceEventListener.class);
+    eventDispatcher.removeEventListener(eventListener);
  }
  @Override
  public final void addDrmEventListener(Handler handler, DrmSessionEventListener eventListener) {
-    addEventListenerInternal(handler, eventListener, DrmSessionEventListener.class);
+    drmEventDispatcher.addEventListener(handler, eventListener);
  }
  @Override
  public final void removeDrmEventListener(DrmSessionEventListener eventListener) {
-    removeEventListenerInternal(eventListener, DrmSessionEventListener.class);
+    drmEventDispatcher.removeEventListener(eventListener);
-  }
-  /**
-   * Adds a listener to the internal {@link MediaSourceEventDispatcher} with the provided type.
-   *
-   * <p>NOTE: Read the caveats on {@link MediaSourceEventDispatcher#addEventListener(Handler,
-   * Object, Class)} when deciding what value to pass for {@code listenerClass}.
-   *
-   * @see MediaSourceEventDispatcher#addEventListener(Handler, Object, Class)
-   */
-  protected final <T> void addEventListenerInternal(
-      Handler handler, T eventListener, Class<T> listenerClass) {
-    eventDispatcher.addEventListener(handler, eventListener, listenerClass);
-  }
-  /**
-   * Removes a listener from the internal {@link MediaSourceEventDispatcher}.
-   *
-   * @see MediaSourceEventDispatcher#removeEventListener(Object, Class)
-   */
-  protected final <T> void removeEventListenerInternal(T eventListener, Class<T> listenerClass) {
-    eventDispatcher.removeEventListener(eventListener, listenerClass);
  }
  @Override

--- a/library/core/src/main/java/com/google/android/exoplayer2/source/CompositeMediaSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/CompositeMediaSource.java
@@ -222,10 +222,12 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
      implements MediaSourceEventListener, DrmSessionEventListener {
    @UnknownNull private final T id;
-    private EventDispatcher eventDispatcher;
+    private MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher;
+    private DrmSessionEventListener.EventDispatcher drmEventDispatcher;
    public ForwardingEventListener(@UnknownNull T id) {
-      this.eventDispatcher = createEventDispatcher(/* mediaPeriodId= */ null);
+      this.mediaSourceEventDispatcher = createEventDispatcher(/* mediaPeriodId= */ null);
+      this.drmEventDispatcher = createDrmEventDispatcher(/* mediaPeriodId= */ null);
      this.id = id;
    }
@@ -235,8 +237,8 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
    public void onMediaPeriodCreated(int windowIndex, MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
        if (shouldDispatchCreateOrReleaseEvent(
-            Assertions.checkNotNull(eventDispatcher.mediaPeriodId))) {
+            Assertions.checkNotNull(mediaSourceEventDispatcher.mediaPeriodId))) {
-          eventDispatcher.mediaPeriodCreated();
+          mediaSourceEventDispatcher.mediaPeriodCreated();
        }
      }
    }
@@ -245,8 +247,8 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
    public void onMediaPeriodReleased(int windowIndex, MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
        if (shouldDispatchCreateOrReleaseEvent(
-            Assertions.checkNotNull(eventDispatcher.mediaPeriodId))) {
+            Assertions.checkNotNull(mediaSourceEventDispatcher.mediaPeriodId))) {
-          eventDispatcher.mediaPeriodReleased();
+          mediaSourceEventDispatcher.mediaPeriodReleased();
        }
      }
    }
@@ -258,7 +260,8 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
        LoadEventInfo loadEventData,
        MediaLoadData mediaLoadData) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.loadStarted(loadEventData, maybeUpdateMediaLoadData(mediaLoadData));
+        mediaSourceEventDispatcher.loadStarted(
+            loadEventData, maybeUpdateMediaLoadData(mediaLoadData));
      }
    }
@@ -269,7 +272,8 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
        LoadEventInfo loadEventData,
        MediaLoadData mediaLoadData) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.loadCompleted(loadEventData, maybeUpdateMediaLoadData(mediaLoadData));
+        mediaSourceEventDispatcher.loadCompleted(
+            loadEventData, maybeUpdateMediaLoadData(mediaLoadData));
      }
    }
@@ -280,7 +284,8 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
        LoadEventInfo loadEventData,
        MediaLoadData mediaLoadData) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.loadCanceled(loadEventData, maybeUpdateMediaLoadData(mediaLoadData));
+        mediaSourceEventDispatcher.loadCanceled(
+            loadEventData, maybeUpdateMediaLoadData(mediaLoadData));
      }
    }
@@ -293,7 +298,7 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
        IOException error,
        boolean wasCanceled) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.loadError(
+        mediaSourceEventDispatcher.loadError(
            loadEventData, maybeUpdateMediaLoadData(mediaLoadData), error, wasCanceled);
      }
    }
@@ -301,7 +306,7 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
    @Override
    public void onReadingStarted(int windowIndex, MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.readingStarted();
+        mediaSourceEventDispatcher.readingStarted();
      }
    }
@@ -309,7 +314,7 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
    public void onUpstreamDiscarded(
        int windowIndex, @Nullable MediaPeriodId mediaPeriodId, MediaLoadData mediaLoadData) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.upstreamDiscarded(maybeUpdateMediaLoadData(mediaLoadData));
+        mediaSourceEventDispatcher.upstreamDiscarded(maybeUpdateMediaLoadData(mediaLoadData));
      }
    }
@@ -317,7 +322,7 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
    public void onDownstreamFormatChanged(
        int windowIndex, @Nullable MediaPeriodId mediaPeriodId, MediaLoadData mediaLoadData) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.downstreamFormatChanged(maybeUpdateMediaLoadData(mediaLoadData));
+        mediaSourceEventDispatcher.downstreamFormatChanged(maybeUpdateMediaLoadData(mediaLoadData));
      }
    }
@@ -326,16 +331,14 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
    @Override
    public void onDrmSessionAcquired(int windowIndex, @Nullable MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.dispatch(
+        drmEventDispatcher.drmSessionAcquired();
-            DrmSessionEventListener::onDrmSessionAcquired, DrmSessionEventListener.class);
      }
    }
    @Override
    public void onDrmKeysLoaded(int windowIndex, @Nullable MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.dispatch(
+        drmEventDispatcher.drmKeysLoaded();
-            DrmSessionEventListener::onDrmKeysLoaded, DrmSessionEventListener.class);
      }
    }
@@ -343,34 +346,28 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
    public void onDrmSessionManagerError(
        int windowIndex, @Nullable MediaPeriodId mediaPeriodId, Exception error) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.dispatch(
+        drmEventDispatcher.drmSessionManagerError(error);
-            (listener, innerWindowIndex, innerMediaPeriodId) ->
-                listener.onDrmSessionManagerError(innerWindowIndex, innerMediaPeriodId, error),
-            DrmSessionEventListener.class);
      }
    }
    @Override
    public void onDrmKeysRestored(int windowIndex, @Nullable MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.dispatch(
+        drmEventDispatcher.drmKeysRestored();
-            DrmSessionEventListener::onDrmKeysRestored, DrmSessionEventListener.class);
      }
    }
    @Override
    public void onDrmKeysRemoved(int windowIndex, @Nullable MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.dispatch(
+        drmEventDispatcher.drmKeysRemoved();
-            DrmSessionEventListener::onDrmKeysRemoved, DrmSessionEventListener.class);
      }
    }
    @Override
    public void onDrmSessionReleased(int windowIndex, @Nullable MediaPeriodId mediaPeriodId) {
      if (maybeUpdateEventDispatcher(windowIndex, mediaPeriodId)) {
-        eventDispatcher.dispatch(
+        drmEventDispatcher.drmSessionReleased();
-            DrmSessionEventListener::onDrmSessionReleased, DrmSessionEventListener.class);
      }
    }
@@ -386,11 +383,15 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
        }
      }
      int windowIndex = getWindowIndexForChildWindowIndex(id, childWindowIndex);
-      if (eventDispatcher.windowIndex != windowIndex
+      if (mediaSourceEventDispatcher.windowIndex != windowIndex
-          || !Util.areEqual(eventDispatcher.mediaPeriodId, mediaPeriodId)) {
+          || !Util.areEqual(mediaSourceEventDispatcher.mediaPeriodId, mediaPeriodId)) {
-        eventDispatcher =
+        mediaSourceEventDispatcher =
            createEventDispatcher(windowIndex, mediaPeriodId, /* mediaTimeOffsetMs= */ 0);
      }
+      if (drmEventDispatcher.windowIndex != windowIndex
+          || !Util.areEqual(drmEventDispatcher.mediaPeriodId, mediaPeriodId)) {
+        drmEventDispatcher = createDrmEventDispatcher(windowIndex, mediaPeriodId);
+      }
      return true;
    }

--- a/library/core/src/main/java/com/google/android/exoplayer2/source/MediaSourceEventListener.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/MediaSourceEventListener.java
@@ -15,15 +15,17 @@
 */
 package com.google.android.exoplayer2.source;
+import android.os.Handler;
+import android.os.Looper;
+import androidx.annotation.CheckResult;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
 import com.google.android.exoplayer2.util.Assertions;
-import com.google.android.exoplayer2.util.CopyOnWriteMultiset;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import java.io.IOException;
+import java.util.concurrent.CopyOnWriteArrayList;
 /** Interface for callbacks to be notified of {@link MediaSource} events. */
 public interface MediaSourceEventListener {
@@ -160,42 +162,101 @@ public interface MediaSourceEventListener {
  default void onDownstreamFormatChanged(
      int windowIndex, @Nullable MediaPeriodId mediaPeriodId, MediaLoadData mediaLoadData) {}
-  /** @deprecated Use {@link MediaSourceEventDispatcher} directly instead. */
+  /** Dispatches events to {@link MediaSourceEventListener MediaSourceEventListeners}. */
-  @Deprecated
+  class EventDispatcher {
-  final class EventDispatcher extends MediaSourceEventDispatcher {
+    /** The timeline window index reported with the events. */
+    public final int windowIndex;
+    /** The {@link MediaPeriodId} reported with the events. */
+    @Nullable public final MediaPeriodId mediaPeriodId;
+    private final CopyOnWriteArrayList<ListenerAndHandler> listenerAndHandlers;
+    private final long mediaTimeOffsetMs;
+    /** Creates an event dispatcher. */
    public EventDispatcher() {
-      super();
+      this(
+          /* listenerAndHandlers= */ new CopyOnWriteArrayList<>(),
+          /* windowIndex= */ 0,
+          /* mediaPeriodId= */ null,
+          /* mediaTimeOffsetMs= */ 0);
    }
    private EventDispatcher(
-        CopyOnWriteMultiset<ListenerInfo> listeners,
+        CopyOnWriteArrayList<ListenerAndHandler> listenerAndHandlers,
        int windowIndex,
        @Nullable MediaPeriodId mediaPeriodId,
        long mediaTimeOffsetMs) {
-      super(listeners, windowIndex, mediaPeriodId, mediaTimeOffsetMs);
+      this.listenerAndHandlers = listenerAndHandlers;
+      this.windowIndex = windowIndex;
+      this.mediaPeriodId = mediaPeriodId;
+      this.mediaTimeOffsetMs = mediaTimeOffsetMs;
    }
-    @Override
+    /**
+     * Creates a view of the event dispatcher with pre-configured window index, media period id, and
+     * media time offset.
+     *
+     * @param windowIndex The timeline window index to be reported with the events.
+     * @param mediaPeriodId The {@link MediaPeriodId} to be reported with the events.
+     * @param mediaTimeOffsetMs The offset to be added to all media times, in milliseconds.
+     * @return A view of the event dispatcher with the pre-configured parameters.
+     */
+    @CheckResult
    public EventDispatcher withParameters(
        int windowIndex, @Nullable MediaPeriodId mediaPeriodId, long mediaTimeOffsetMs) {
-      return new EventDispatcher(listenerInfos, windowIndex, mediaPeriodId, mediaTimeOffsetMs);
+      return new EventDispatcher(
+          listenerAndHandlers, windowIndex, mediaPeriodId, mediaTimeOffsetMs);
+    }
+    /**
+     * Adds a listener to the event dispatcher.
+     *
+     * @param handler A handler on the which listener events will be posted.
+     * @param eventListener The listener to be added.
+     */
+    public void addEventListener(Handler handler, MediaSourceEventListener eventListener) {
+      Assertions.checkNotNull(handler);
+      Assertions.checkNotNull(eventListener);
+      listenerAndHandlers.add(new ListenerAndHandler(handler, eventListener));
    }
+    /**
+     * Removes a listener from the event dispatcher.
+     *
+     * @param eventListener The listener to be removed.
+     */
+    public void removeEventListener(MediaSourceEventListener eventListener) {
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
+        if (listenerAndHandler.listener == eventListener) {
+          listenerAndHandlers.remove(listenerAndHandler);
+        }
+      }
+    }
+    /** Dispatches {@link #onMediaPeriodCreated(int, MediaPeriodId)}. */
    public void mediaPeriodCreated() {
-      dispatch(
+      MediaPeriodId mediaPeriodId = Assertions.checkNotNull(this.mediaPeriodId);
-          (listener, windowIndex, mediaPeriodId) ->
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
-              listener.onMediaPeriodCreated(windowIndex, Assertions.checkNotNull(mediaPeriodId)),
+        MediaSourceEventListener listener = listenerAndHandler.listener;
-          MediaSourceEventListener.class);
+        postOrRun(
+            listenerAndHandler.handler,
+            () -> listener.onMediaPeriodCreated(windowIndex, mediaPeriodId));
+      }
    }
+    /** Dispatches {@link #onMediaPeriodReleased(int, MediaPeriodId)}. */
    public void mediaPeriodReleased() {
-      dispatch(
+      MediaPeriodId mediaPeriodId = Assertions.checkNotNull(this.mediaPeriodId);
-          (listener, windowIndex, mediaPeriodId) ->
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
-              listener.onMediaPeriodReleased(windowIndex, Assertions.checkNotNull(mediaPeriodId)),
+        MediaSourceEventListener listener = listenerAndHandler.listener;
-          MediaSourceEventListener.class);
+        postOrRun(
+            listenerAndHandler.handler,
+            () -> listener.onMediaPeriodReleased(windowIndex, mediaPeriodId));
+      }
    }
+    /** Dispatches {@link #onLoadStarted(int, MediaPeriodId, LoadEventInfo, MediaLoadData)}. */
    public void loadStarted(LoadEventInfo loadEventInfo, int dataType) {
      loadStarted(
          loadEventInfo,
@@ -208,6 +269,7 @@ public interface MediaSourceEventListener {
          /* mediaEndTimeUs= */ C.TIME_UNSET);
    }
+    /** Dispatches {@link #onLoadStarted(int, MediaPeriodId, LoadEventInfo, MediaLoadData)}. */
    public void loadStarted(
        LoadEventInfo loadEventInfo,
        int dataType,
@@ -229,13 +291,17 @@ public interface MediaSourceEventListener {
              adjustMediaTime(mediaEndTimeUs)));
    }
+    /** Dispatches {@link #onLoadStarted(int, MediaPeriodId, LoadEventInfo, MediaLoadData)}. */
    public void loadStarted(LoadEventInfo loadEventInfo, MediaLoadData mediaLoadData) {
-      dispatch(
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
-          (listener, windowIndex, mediaPeriodId) ->
+        MediaSourceEventListener listener = listenerAndHandler.listener;
-              listener.onLoadStarted(windowIndex, mediaPeriodId, loadEventInfo, mediaLoadData),
+        postOrRun(
-          MediaSourceEventListener.class);
+            listenerAndHandler.handler,
+            () -> listener.onLoadStarted(windowIndex, mediaPeriodId, loadEventInfo, mediaLoadData));
+      }
    }
+    /** Dispatches {@link #onLoadCompleted(int, MediaPeriodId, LoadEventInfo, MediaLoadData)}. */
    public void loadCompleted(LoadEventInfo loadEventInfo, int dataType) {
      loadCompleted(
          loadEventInfo,
@@ -248,6 +314,7 @@ public interface MediaSourceEventListener {
          /* mediaEndTimeUs= */ C.TIME_UNSET);
    }
+    /** Dispatches {@link #onLoadCompleted(int, MediaPeriodId, LoadEventInfo, MediaLoadData)}. */
    public void loadCompleted(
        LoadEventInfo loadEventInfo,
        int dataType,
@@ -269,13 +336,18 @@ public interface MediaSourceEventListener {
              adjustMediaTime(mediaEndTimeUs)));
    }
+    /** Dispatches {@link #onLoadCompleted(int, MediaPeriodId, LoadEventInfo, MediaLoadData)}. */
    public void loadCompleted(LoadEventInfo loadEventInfo, MediaLoadData mediaLoadData) {
-      dispatch(
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
-          (listener, windowIndex, mediaPeriodId) ->
+        MediaSourceEventListener listener = listenerAndHandler.listener;
-              listener.onLoadCompleted(windowIndex, mediaPeriodId, loadEventInfo, mediaLoadData),
+        postOrRun(
-          MediaSourceEventListener.class);
+            listenerAndHandler.handler,
+            () ->
+                listener.onLoadCompleted(windowIndex, mediaPeriodId, loadEventInfo, mediaLoadData));
+      }
    }
+    /** Dispatches {@link #onLoadCanceled(int, MediaPeriodId, LoadEventInfo, MediaLoadData)}. */
    public void loadCanceled(LoadEventInfo loadEventInfo, int dataType) {
      loadCanceled(
          loadEventInfo,
@@ -288,6 +360,7 @@ public interface MediaSourceEventListener {
          /* mediaEndTimeUs= */ C.TIME_UNSET);
    }
+    /** Dispatches {@link #onLoadCanceled(int, MediaPeriodId, LoadEventInfo, MediaLoadData)}. */
    public void loadCanceled(
        LoadEventInfo loadEventInfo,
        int dataType,
@@ -309,13 +382,21 @@ public interface MediaSourceEventListener {
              adjustMediaTime(mediaEndTimeUs)));
    }
+    /** Dispatches {@link #onLoadCanceled(int, MediaPeriodId, LoadEventInfo, MediaLoadData)}. */
    public void loadCanceled(LoadEventInfo loadEventInfo, MediaLoadData mediaLoadData) {
-      dispatch(
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
-          (listener, windowIndex, mediaPeriodId) ->
+        MediaSourceEventListener listener = listenerAndHandler.listener;
-              listener.onLoadCanceled(windowIndex, mediaPeriodId, loadEventInfo, mediaLoadData),
+        postOrRun(
-          MediaSourceEventListener.class);
+            listenerAndHandler.handler,
+            () ->
+                listener.onLoadCanceled(windowIndex, mediaPeriodId, loadEventInfo, mediaLoadData));
+      }
    }
+    /**
+     * Dispatches {@link #onLoadError(int, MediaPeriodId, LoadEventInfo, MediaLoadData, IOException,
+     * boolean)}.
+     */
    public void loadError(
        LoadEventInfo loadEventInfo, int dataType, IOException error, boolean wasCanceled) {
      loadError(
@@ -331,6 +412,10 @@ public interface MediaSourceEventListener {
          wasCanceled);
    }
+    /**
+     * Dispatches {@link #onLoadError(int, MediaPeriodId, LoadEventInfo, MediaLoadData, IOException,
+     * boolean)}.
+     */
    public void loadError(
        LoadEventInfo loadEventInfo,
        int dataType,
@@ -356,25 +441,37 @@ public interface MediaSourceEventListener {
          wasCanceled);
    }
+    /**
+     * Dispatches {@link #onLoadError(int, MediaPeriodId, LoadEventInfo, MediaLoadData, IOException,
+     * boolean)}.
+     */
    public void loadError(
        LoadEventInfo loadEventInfo,
        MediaLoadData mediaLoadData,
        IOException error,
        boolean wasCanceled) {
-      dispatch(
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
-          (listener, windowIndex, mediaPeriodId) ->
+        MediaSourceEventListener listener = listenerAndHandler.listener;
+        postOrRun(
+            listenerAndHandler.handler,
+            () ->
                listener.onLoadError(
-                  windowIndex, mediaPeriodId, loadEventInfo, mediaLoadData, error, wasCanceled),
+                    windowIndex, mediaPeriodId, loadEventInfo, mediaLoadData, error, wasCanceled));
-          MediaSourceEventListener.class);
+      }
    }
+    /** Dispatches {@link #onReadingStarted(int, MediaPeriodId)}. */
    public void readingStarted() {
-      dispatch(
+      MediaPeriodId mediaPeriodId = Assertions.checkNotNull(this.mediaPeriodId);
-          (listener, windowIndex, mediaPeriodId) ->
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
-              listener.onReadingStarted(windowIndex, Assertions.checkNotNull(mediaPeriodId)),
+        MediaSourceEventListener listener = listenerAndHandler.listener;
-          MediaSourceEventListener.class);
+        postOrRun(
+            listenerAndHandler.handler,
+            () -> listener.onReadingStarted(windowIndex, mediaPeriodId));
+      }
    }
+    /** Dispatches {@link #onUpstreamDiscarded(int, MediaPeriodId, MediaLoadData)}. */
    public void upstreamDiscarded(int trackType, long mediaStartTimeUs, long mediaEndTimeUs) {
      upstreamDiscarded(
          new MediaLoadData(
@@ -387,14 +484,18 @@ public interface MediaSourceEventListener {
              adjustMediaTime(mediaEndTimeUs)));
    }
+    /** Dispatches {@link #onUpstreamDiscarded(int, MediaPeriodId, MediaLoadData)}. */
    public void upstreamDiscarded(MediaLoadData mediaLoadData) {
-      dispatch(
+      MediaPeriodId mediaPeriodId = Assertions.checkNotNull(this.mediaPeriodId);
-          (listener, windowIndex, mediaPeriodId) ->
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
-              listener.onUpstreamDiscarded(
+        MediaSourceEventListener listener = listenerAndHandler.listener;
-                  windowIndex, Assertions.checkNotNull(mediaPeriodId), mediaLoadData),
+        postOrRun(
-          MediaSourceEventListener.class);
+            listenerAndHandler.handler,
+            () -> listener.onUpstreamDiscarded(windowIndex, mediaPeriodId, mediaLoadData));
+      }
    }
+    /** Dispatches {@link #onDownstreamFormatChanged(int, MediaPeriodId, MediaLoadData)}. */
    public void downstreamFormatChanged(
        int trackType,
        @Nullable Format trackFormat,
@@ -412,15 +513,38 @@ public interface MediaSourceEventListener {
              /* mediaEndTimeMs= */ C.TIME_UNSET));
    }
+    /** Dispatches {@link #onDownstreamFormatChanged(int, MediaPeriodId, MediaLoadData)}. */
    public void downstreamFormatChanged(MediaLoadData mediaLoadData) {
-      dispatch(
+      for (ListenerAndHandler listenerAndHandler : listenerAndHandlers) {
-          (listener, windowIndex, mediaPeriodId) ->
+        MediaSourceEventListener listener = listenerAndHandler.listener;
-              listener.onDownstreamFormatChanged(windowIndex, mediaPeriodId, mediaLoadData),
+        postOrRun(
-          MediaSourceEventListener.class);
+            listenerAndHandler.handler,
+            () -> listener.onDownstreamFormatChanged(windowIndex, mediaPeriodId, mediaLoadData));
+      }
    }
    private long adjustMediaTime(long mediaTimeUs) {
-      return adjustMediaTime(mediaTimeUs, mediaTimeOffsetMs);
+      long mediaTimeMs = C.usToMs(mediaTimeUs);
+      return mediaTimeMs == C.TIME_UNSET ? C.TIME_UNSET : mediaTimeOffsetMs + mediaTimeMs;
+    }
+    private static void postOrRun(Handler handler, Runnable runnable) {
+      if (handler.getLooper() == Looper.myLooper()) {
+        runnable.run();
+      } else {
+        handler.post(runnable);
+      }
+    }
+    private static final class ListenerAndHandler {
+      public Handler handler;
+      public MediaSourceEventListener listener;
+      public ListenerAndHandler(Handler handler, MediaSourceEventListener listener) {
+        this.handler = handler;
+        this.listener = listener;
+      }
    }
  }
 }
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/ProgressiveMediaPeriod.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/ProgressiveMediaPeriod.java
@@ -24,6 +24,7 @@ import com.google.android.exoplayer2.FormatHolder;
 import com.google.android.exoplayer2.ParserException;
 import com.google.android.exoplayer2.SeekParameters;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.extractor.Extractor;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
@@ -35,7 +36,6 @@ import com.google.android.exoplayer2.extractor.SeekMap.Unseekable;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.icy.IcyHeaders;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
 import com.google.android.exoplayer2.source.SampleQueue.UpstreamFormatChangedListener;
 import com.google.android.exoplayer2.trackselection.TrackSelection;
 import com.google.android.exoplayer2.upstream.Allocator;
@@ -101,7 +101,8 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
  private final DataSource dataSource;
  private final DrmSessionManager drmSessionManager;
  private final LoadErrorHandlingPolicy loadErrorHandlingPolicy;
-  private final EventDispatcher eventDispatcher;
+  private final MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher;
+  private final DrmSessionEventListener.EventDispatcher drmEventDispatcher;
  private final Listener listener;
  private final Allocator allocator;
  @Nullable private final String customCacheKey;
@@ -145,8 +146,11 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   * @param uri The {@link Uri} of the media stream.
   * @param dataSource The data source to read the media.
   * @param extractorsFactory The {@link ExtractorsFactory} to use to read the data source.
+   * @param drmSessionManager A {@link DrmSessionManager} to allow DRM interactions.
+   * @param drmEventDispatcher A dispatcher to notify of {@link DrmSessionEventListener} events.
   * @param loadErrorHandlingPolicy The {@link LoadErrorHandlingPolicy}.
-   * @param eventDispatcher A dispatcher to notify of events.
+   * @param mediaSourceEventDispatcher A dispatcher to notify of {@link MediaSourceEventListener}
+   *     events.
   * @param listener A listener to notify when information about the period changes.
   * @param allocator An {@link Allocator} from which to obtain media buffer allocations.
   * @param customCacheKey A custom key that uniquely identifies the original stream. Used for cache
@@ -164,8 +168,9 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
      DataSource dataSource,
      ExtractorsFactory extractorsFactory,
      DrmSessionManager drmSessionManager,
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher,
      LoadErrorHandlingPolicy loadErrorHandlingPolicy,
-      EventDispatcher eventDispatcher,
+      MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
      Listener listener,
      Allocator allocator,
      @Nullable String customCacheKey,
@@ -173,8 +178,9 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
    this.uri = uri;
    this.dataSource = dataSource;
    this.drmSessionManager = drmSessionManager;
+    this.drmEventDispatcher = drmEventDispatcher;
    this.loadErrorHandlingPolicy = loadErrorHandlingPolicy;
-    this.eventDispatcher = eventDispatcher;
+    this.mediaSourceEventDispatcher = mediaSourceEventDispatcher;
    this.listener = listener;
    this.allocator = allocator;
    this.customCacheKey = customCacheKey;
@@ -199,7 +205,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
    length = C.LENGTH_UNSET;
    durationUs = C.TIME_UNSET;
    dataType = C.DATA_TYPE_MEDIA;
-    eventDispatcher.mediaPeriodCreated();
+    mediaSourceEventDispatcher.mediaPeriodCreated();
  }
  public void release() {
@@ -214,7 +220,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
    handler.removeCallbacksAndMessages(null);
    callback = null;
    released = true;
-    eventDispatcher.mediaPeriodReleased();
+    mediaSourceEventDispatcher.mediaPeriodReleased();
  }
  @Override
@@ -369,7 +375,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
  @Override
  public long readDiscontinuity() {
    if (!notifiedReadingStarted) {
-      eventDispatcher.readingStarted();
+      mediaSourceEventDispatcher.readingStarted();
      notifiedReadingStarted = true;
    }
    if (notifyDiscontinuity
@@ -510,7 +516,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
    boolean[] trackNotifiedDownstreamFormats = trackState.trackNotifiedDownstreamFormats;
    if (!trackNotifiedDownstreamFormats[track]) {
      Format trackFormat = trackState.tracks.get(track).getFormat(/* index= */ 0);
-      eventDispatcher.downstreamFormatChanged(
+      mediaSourceEventDispatcher.downstreamFormatChanged(
          MimeTypes.getTrackType(trackFormat.sampleMimeType),
          trackFormat,
          C.SELECTION_REASON_UNKNOWN,
@@ -566,7 +572,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
            loadDurationMs,
            dataSource.getBytesRead());
    loadErrorHandlingPolicy.onLoadTaskConcluded(loadable.loadTaskId);
-    eventDispatcher.loadCompleted(
+    mediaSourceEventDispatcher.loadCompleted(
        loadEventInfo,
        C.DATA_TYPE_MEDIA,
        C.TRACK_TYPE_UNKNOWN,
@@ -594,7 +600,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
            loadDurationMs,
            dataSource.getBytesRead());
    loadErrorHandlingPolicy.onLoadTaskConcluded(loadable.loadTaskId);
-    eventDispatcher.loadCanceled(
+    mediaSourceEventDispatcher.loadCanceled(
        loadEventInfo,
        C.DATA_TYPE_MEDIA,
        C.TRACK_TYPE_UNKNOWN,
@@ -657,7 +663,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
    }
    boolean wasCanceled = !loadErrorAction.isRetry();
-    eventDispatcher.loadError(
+    mediaSourceEventDispatcher.loadError(
        loadEventInfo,
        C.DATA_TYPE_MEDIA,
        C.TRACK_TYPE_UNKNOWN,
@@ -719,7 +725,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
            allocator,
            /* playbackLooper= */ handler.getLooper(),
            drmSessionManager,
-            eventDispatcher);
+            drmEventDispatcher);
    trackOutput.setUpstreamFormatChangeListener(this);
    @NullableType
    TrackId[] sampleQueueTrackIds = Arrays.copyOf(this.sampleQueueTrackIds, trackCount + 1);
@@ -824,7 +830,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
        loader.startLoading(
            loadable, this, loadErrorHandlingPolicy.getMinimumLoadableRetryCount(dataType));
    DataSpec dataSpec = loadable.dataSpec;
-    eventDispatcher.loadStarted(
+    mediaSourceEventDispatcher.loadStarted(
        new LoadEventInfo(loadable.loadTaskId, dataSpec, elapsedRealtimeMs),
        C.DATA_TYPE_MEDIA,
        C.TRACK_TYPE_UNKNOWN,

--- a/library/core/src/main/java/com/google/android/exoplayer2/source/ProgressiveMediaSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/ProgressiveMediaSource.java
@@ -283,6 +283,7 @@ public final class ProgressiveMediaSource extends BaseMediaSource
        dataSource,
        extractorsFactory,
        drmSessionManager,
+        createDrmEventDispatcher(id),
        loadableLoadErrorHandlingPolicy,
        createEventDispatcher(id),
        this,

--- a/library/core/src/main/java/com/google/android/exoplayer2/source/SampleQueue.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/SampleQueue.java
@@ -26,12 +26,12 @@ import com.google.android.exoplayer2.FormatHolder;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
 import com.google.android.exoplayer2.drm.DrmInitData;
 import com.google.android.exoplayer2.drm.DrmSession;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.upstream.DataReader;
 import com.google.android.exoplayer2.util.Assertions;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.Util;
@@ -59,7 +59,7 @@ public class SampleQueue implements TrackOutput {
  private final SampleExtrasHolder extrasHolder;
  private final Looper playbackLooper;
  private final DrmSessionManager drmSessionManager;
-  private final MediaSourceEventDispatcher eventDispatcher;
+  private final DrmSessionEventListener.EventDispatcher drmEventDispatcher;
  @Nullable private UpstreamFormatChangedListener upstreamFormatChangeListener;
  @Nullable private Format downstreamFormat;
@@ -103,17 +103,17 @@ public class SampleQueue implements TrackOutput {
   * @param playbackLooper The looper associated with the media playback thread.
   * @param drmSessionManager The {@link DrmSessionManager} to obtain {@link DrmSession DrmSessions}
   *     from. The created instance does not take ownership of this {@link DrmSessionManager}.
-   * @param eventDispatcher A {@link MediaSourceEventDispatcher} to notify of events related to this
+   * @param drmEventDispatcher A {@link DrmSessionEventListener.EventDispatcher} to notify of events
-   *     SampleQueue.
+   *     related to this SampleQueue.
   */
  public SampleQueue(
      Allocator allocator,
      Looper playbackLooper,
      DrmSessionManager drmSessionManager,
-      MediaSourceEventDispatcher eventDispatcher) {
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher) {
    this.playbackLooper = playbackLooper;
    this.drmSessionManager = drmSessionManager;
-    this.eventDispatcher = eventDispatcher;
+    this.drmEventDispatcher = drmEventDispatcher;
    sampleDataQueue = new SampleDataQueue(allocator);
    extrasHolder = new SampleExtrasHolder();
    capacity = SAMPLE_CAPACITY_INCREMENT;
@@ -691,7 +691,7 @@ public class SampleQueue implements TrackOutput {
  private void releaseDrmSessionReferences() {
    if (currentDrmSession != null) {
-      currentDrmSession.release(eventDispatcher);
+      currentDrmSession.release(drmEventDispatcher);
      currentDrmSession = null;
      // Clear downstream format to avoid violating the assumption that downstreamFormat.drmInitData
      // != null implies currentSession != null
@@ -826,13 +826,13 @@ public class SampleQueue implements TrackOutput {
    @Nullable DrmSession previousSession = currentDrmSession;
    currentDrmSession =
        newDrmInitData != null
-            ? drmSessionManager.acquireSession(playbackLooper, eventDispatcher, newDrmInitData)
+            ? drmSessionManager.acquireSession(playbackLooper, drmEventDispatcher, newDrmInitData)
            : drmSessionManager.acquirePlaceholderSession(
                playbackLooper, MimeTypes.getTrackType(newFormat.sampleMimeType));
    outputFormatHolder.drmSession = currentDrmSession;
    if (previousSession != null) {
-      previousSession.release(eventDispatcher);
+      previousSession.release(drmEventDispatcher);
    }
  }

--- a/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/ChunkSampleStream.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/ChunkSampleStream.java
@@ -23,10 +23,11 @@ import com.google.android.exoplayer2.FormatHolder;
 import com.google.android.exoplayer2.SeekParameters;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
 import com.google.android.exoplayer2.drm.DrmSession;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.source.LoadEventInfo;
 import com.google.android.exoplayer2.source.MediaLoadData;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.SampleQueue;
 import com.google.android.exoplayer2.source.SampleStream;
 import com.google.android.exoplayer2.source.SequenceableLoader;
@@ -71,7 +72,7 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
  private final boolean[] embeddedTracksSelected;
  private final T chunkSource;
  private final SequenceableLoader.Callback<ChunkSampleStream<T>> callback;
-  private final EventDispatcher eventDispatcher;
+  private final MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher;
  private final LoadErrorHandlingPolicy loadErrorHandlingPolicy;
  private final Loader loader;
  private final ChunkHolder nextChunkHolder;
@@ -102,8 +103,10 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
   * @param positionUs The position from which to start loading media.
   * @param drmSessionManager The {@link DrmSessionManager} to obtain {@link DrmSession DrmSessions}
   *     from.
+   * @param drmEventDispatcher A dispatcher to notify of {@link DrmSessionEventListener} events.
   * @param loadErrorHandlingPolicy The {@link LoadErrorHandlingPolicy}.
-   * @param eventDispatcher A dispatcher to notify of events.
+   * @param mediaSourceEventDispatcher A dispatcher to notify of {@link MediaSourceEventListener}
+   *     events.
   */
  public ChunkSampleStream(
      int primaryTrackType,
@@ -114,14 +117,15 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
      Allocator allocator,
      long positionUs,
      DrmSessionManager drmSessionManager,
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher,
      LoadErrorHandlingPolicy loadErrorHandlingPolicy,
-      EventDispatcher eventDispatcher) {
+      MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher) {
    this.primaryTrackType = primaryTrackType;
    this.embeddedTrackTypes = embeddedTrackTypes == null ? new int[0] : embeddedTrackTypes;
    this.embeddedTrackFormats = embeddedTrackFormats == null ? new Format[0] : embeddedTrackFormats;
    this.chunkSource = chunkSource;
    this.callback = callback;
-    this.eventDispatcher = eventDispatcher;
+    this.mediaSourceEventDispatcher = mediaSourceEventDispatcher;
    this.loadErrorHandlingPolicy = loadErrorHandlingPolicy;
    loader = new Loader("Loader:ChunkSampleStream");
    nextChunkHolder = new ChunkHolder();
@@ -139,7 +143,7 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
            allocator,
            /* playbackLooper= */ Assertions.checkNotNull(Looper.myLooper()),
            drmSessionManager,
-            eventDispatcher);
+            drmEventDispatcher);
    trackTypes[0] = primaryTrackType;
    sampleQueues[0] = primarySampleQueue;
@@ -149,7 +153,7 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
              allocator,
              /* playbackLooper= */ Assertions.checkNotNull(Looper.myLooper()),
              DrmSessionManager.getDummyDrmSessionManager(),
-              eventDispatcher);
+              drmEventDispatcher);
      embeddedSampleQueues[i] = sampleQueue;
      sampleQueues[i + 1] = sampleQueue;
      trackTypes[i + 1] = this.embeddedTrackTypes[i];
@@ -413,7 +417,7 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
            loadDurationMs,
            loadable.bytesLoaded());
    loadErrorHandlingPolicy.onLoadTaskConcluded(loadable.loadTaskId);
-    eventDispatcher.loadCompleted(
+    mediaSourceEventDispatcher.loadCompleted(
        loadEventInfo,
        loadable.type,
        primaryTrackType,
@@ -438,7 +442,7 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
            loadDurationMs,
            loadable.bytesLoaded());
    loadErrorHandlingPolicy.onLoadTaskConcluded(loadable.loadTaskId);
-    eventDispatcher.loadCanceled(
+    mediaSourceEventDispatcher.loadCanceled(
        loadEventInfo,
        loadable.type,
        primaryTrackType,
@@ -519,7 +523,7 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
    }
    boolean canceled = !loadErrorAction.isRetry();
-    eventDispatcher.loadError(
+    mediaSourceEventDispatcher.loadError(
        loadEventInfo,
        loadable.type,
        primaryTrackType,
@@ -593,7 +597,7 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
    long elapsedRealtimeMs =
        loader.startLoading(
            loadable, this, loadErrorHandlingPolicy.getMinimumLoadableRetryCount(loadable.type));
-    eventDispatcher.loadStarted(
+    mediaSourceEventDispatcher.loadStarted(
        new LoadEventInfo(loadable.loadTaskId, loadable.dataSpec, elapsedRealtimeMs),
        loadable.type,
        primaryTrackType,
@@ -648,7 +652,8 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
      pendingResetPositionUs = lastSeekPositionUs;
    }
    loadingFinished = false;
-    eventDispatcher.upstreamDiscarded(primaryTrackType, firstRemovedChunk.startTimeUs, endTimeUs);
+    mediaSourceEventDispatcher.upstreamDiscarded(
+        primaryTrackType, firstRemovedChunk.startTimeUs, endTimeUs);
  }
  // Internal methods
@@ -701,8 +706,11 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
    BaseMediaChunk currentChunk = mediaChunks.get(mediaChunkReadIndex);
    Format trackFormat = currentChunk.trackFormat;
    if (!trackFormat.equals(primaryDownstreamTrackFormat)) {
-      eventDispatcher.downstreamFormatChanged(primaryTrackType, trackFormat,
+      mediaSourceEventDispatcher.downstreamFormatChanged(
-          currentChunk.trackSelectionReason, currentChunk.trackSelectionData,
+          primaryTrackType,
+          trackFormat,
+          currentChunk.trackSelectionReason,
+          currentChunk.trackSelectionData,
          currentChunk.startTimeUs);
    }
    primaryDownstreamTrackFormat = trackFormat;
@@ -812,7 +820,7 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
    private void maybeNotifyDownstreamFormat() {
      if (!notifiedDownstreamFormat) {
-        eventDispatcher.downstreamFormatChanged(
+        mediaSourceEventDispatcher.downstreamFormatChanged(
            embeddedTrackTypes[index],
            embeddedTrackFormats[index],
            C.SELECTION_REASON_UNKNOWN,

--- a/library/core/src/main/java/com/google/android/exoplayer2/util/MediaSourceEventDispatcher.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/util/MediaSourceEventDispatcher.java
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.google.android.exoplayer2.util;
-import android.os.Handler;
-import android.os.Looper;
-import androidx.annotation.CheckResult;
-import androidx.annotation.Nullable;
-import com.google.android.exoplayer2.C;
-import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
-/**
- * Event dispatcher which forwards events to a list of registered listeners.
- *
- * <p>Adds the correct {@code windowIndex} and {@code mediaPeriodId} values (and {@code
- * mediaTimeOffsetMs} if needed).
- *
- * <p>Allows listeners of any type to be registered, calls to {@link #dispatch} then provide the
- * type of listener to forward to, which is used to filter the registered listeners.
- */
-// TODO: Make this final when MediaSourceEventListener.EventDispatcher is deleted.
-public class MediaSourceEventDispatcher {
-  /**
-   * Functional interface to send an event with {@code windowIndex} and {@code mediaPeriodId}
-   * attached.
-   */
-  public interface EventWithPeriodId<T> {
-    /** Sends the event to a listener. */
-    void sendTo(T listener, int windowIndex, @Nullable MediaPeriodId mediaPeriodId);
-  }
-  /** The timeline window index reported with the events. */
-  public final int windowIndex;
-  /** The {@link MediaPeriodId} reported with the events. */
-  @Nullable public final MediaPeriodId mediaPeriodId;
-  // TODO: Make these private when MediaSourceEventListener.EventDispatcher is deleted.
-  protected final CopyOnWriteMultiset<ListenerInfo> listenerInfos;
-  // TODO: Define exactly what this means, and check it's always set correctly.
-  protected final long mediaTimeOffsetMs;
-  /** Creates an event dispatcher. */
-  public MediaSourceEventDispatcher() {
-    this(
-        /* listenerInfos= */ new CopyOnWriteMultiset<>(),
-        /* windowIndex= */ 0,
-        /* mediaPeriodId= */ null,
-        /* mediaTimeOffsetMs= */ 0);
-  }
-  protected MediaSourceEventDispatcher(
-      CopyOnWriteMultiset<ListenerInfo> listenerInfos,
-      int windowIndex,
-      @Nullable MediaPeriodId mediaPeriodId,
-      long mediaTimeOffsetMs) {
-    this.listenerInfos = listenerInfos;
-    this.windowIndex = windowIndex;
-    this.mediaPeriodId = mediaPeriodId;
-    this.mediaTimeOffsetMs = mediaTimeOffsetMs;
-  }
-  /**
-   * Creates a view of the event dispatcher with pre-configured window index, media period id, and
-   * media time offset.
-   *
-   * @param windowIndex The timeline window index to be reported with the events.
-   * @param mediaPeriodId The {@link MediaPeriodId} to be reported with the events.
-   * @param mediaTimeOffsetMs The offset to be added to all media times, in milliseconds.
-   * @return A view of the event dispatcher with the pre-configured parameters.
-   */
-  @CheckResult
-  public MediaSourceEventDispatcher withParameters(
-      int windowIndex, @Nullable MediaPeriodId mediaPeriodId, long mediaTimeOffsetMs) {
-    return new MediaSourceEventDispatcher(
-        listenerInfos, windowIndex, mediaPeriodId, mediaTimeOffsetMs);
-  }
-  /**
-   * Adds a listener to the event dispatcher.
-   *
-   * <p>Calls to {@link #dispatch(EventWithPeriodId, Class)} will propagate to {@code eventListener}
-   * if the {@code listenerClass} types are equal.
-   *
-   * <p>The same listener instance can be added multiple times with different {@code listenerClass}
-   * values (i.e. if the instance implements multiple listener interfaces).
-   *
-   * <p>Duplicate {@code {eventListener, listenerClass}} pairs are also permitted. In this case an
-   * event dispatched to {@code listenerClass} will only be passed to the {@code eventListener}
-   * once.
-   *
-   * <p><b>NOTE</b>: This doesn't interact well with hierarchies of listener interfaces. If a
-   * listener is registered with a super-class type then it will only receive events dispatched
-   * directly to that super-class type. Similarly, if a listener is registered with a sub-class type
-   * then it will only receive events dispatched directly to that sub-class.
-   *
-   * @param handler A handler on the which listener events will be posted.
-   * @param eventListener The listener to be added.
-   * @param listenerClass The type used to register the listener. Can be a superclass of {@code
-   *     eventListener}.
-   */
-  public <T> void addEventListener(Handler handler, T eventListener, Class<T> listenerClass) {
-    Assertions.checkNotNull(handler);
-    Assertions.checkNotNull(eventListener);
-    listenerInfos.add(new ListenerInfo(handler, eventListener, listenerClass));
-  }
-  /**
-   * Removes a listener from the event dispatcher.
-   *
-   * <p>If there are duplicate registrations of {@code {eventListener, listenerClass}} this will
-   * only remove one (so events dispatched to {@code listenerClass} will still be passed to {@code
-   * eventListener}).
-   *
-   * @param eventListener The listener to be removed.
-   * @param listenerClass The listener type passed to {@link #addEventListener(Handler, Object,
-   *     Class)}.
-   */
-  public <T> void removeEventListener(T eventListener, Class<T> listenerClass) {
-    for (ListenerInfo listenerInfo : listenerInfos) {
-      if (listenerInfo.listener == eventListener
-          && listenerInfo.listenerClass.equals(listenerClass)) {
-        listenerInfos.remove(listenerInfo);
-        return;
-      }
-    }
-  }
-  /** Dispatches {@code event} to all registered listeners of type {@code listenerClass}. */
-  @SuppressWarnings("unchecked") // The cast is gated with listenerClass.isInstance()
-  public <T> void dispatch(EventWithPeriodId<T> event, Class<T> listenerClass) {
-    for (ListenerInfo listenerInfo : listenerInfos.elementSet()) {
-      if (listenerInfo.listenerClass.equals(listenerClass)) {
-        postOrRun(
-            listenerInfo.handler,
-            () -> event.sendTo((T) listenerInfo.listener, windowIndex, mediaPeriodId));
-      }
-    }
-  }
-  private static void postOrRun(Handler handler, Runnable runnable) {
-    if (handler.getLooper() == Looper.myLooper()) {
-      runnable.run();
-    } else {
-      handler.post(runnable);
-    }
-  }
-  public static long adjustMediaTime(long mediaTimeUs, long mediaTimeOffsetMs) {
-    long mediaTimeMs = C.usToMs(mediaTimeUs);
-    return mediaTimeMs == C.TIME_UNSET ? C.TIME_UNSET : mediaTimeOffsetMs + mediaTimeMs;
-  }
-  /** Container class for a {@link Handler}, {@code listener} and {@code listenerClass}. */
-  protected static final class ListenerInfo {
-    public final Handler handler;
-    public final Object listener;
-    public final Class<?> listenerClass;
-    public ListenerInfo(Handler handler, Object listener, Class<?> listenerClass) {
-      this.handler = handler;
-      this.listener = listener;
-      this.listenerClass = listenerClass;
-    }
-    @Override
-    public boolean equals(@Nullable Object o) {
-      if (this == o) {
-        return true;
-      }
-      if (!(o instanceof ListenerInfo)) {
-        return false;
-      }
-      ListenerInfo that = (ListenerInfo) o;
-      // We deliberately only consider listener and listenerClass (and not handler) in equals() and
-      // hashcode() because the handler used to process the callbacks is an implementation detail.
-      return listener.equals(that.listener) && listenerClass.equals(that.listenerClass);
-    }
-    @Override
-    public int hashCode() {
-      int result = 31 * listener.hashCode();
-      return result + 31 * listenerClass.hashCode();
-    }
-  }
-}
--- a/library/core/src/test/java/com/google/android/exoplayer2/ExoPlayerTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/ExoPlayerTest.java
@@ -44,6 +44,7 @@ import com.google.android.exoplayer2.Player.EventListener;
 import com.google.android.exoplayer2.Timeline.Window;
 import com.google.android.exoplayer2.analytics.AnalyticsListener;
 import com.google.android.exoplayer2.audio.AudioAttributes;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.source.ClippingMediaSource;
 import com.google.android.exoplayer2.source.CompositeMediaSource;
@@ -53,7 +54,7 @@ import com.google.android.exoplayer2.source.MaskingMediaSource;
 import com.google.android.exoplayer2.source.MediaPeriod;
 import com.google.android.exoplayer2.source.MediaSource;
 import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.SampleStream;
 import com.google.android.exoplayer2.source.SilenceMediaSource;
 import com.google.android.exoplayer2.source.TrackGroup;
@@ -616,15 +617,17 @@ public final class ExoPlayerTest {
              MediaPeriodId id,
              TrackGroupArray trackGroupArray,
              Allocator allocator,
+              MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
              DrmSessionManager drmSessionManager,
-              EventDispatcher eventDispatcher,
+              DrmSessionEventListener.EventDispatcher drmEventDispatcher,
              @Nullable TransferListener transferListener) {
            FakeMediaPeriod mediaPeriod =
                new FakeMediaPeriod(
                    trackGroupArray,
                    TimelineWindowDefinition.DEFAULT_WINDOW_OFFSET_IN_FIRST_PERIOD_US,
-                    eventDispatcher,
+                    mediaSourceEventDispatcher,
                    drmSessionManager,
+                    drmEventDispatcher,
                    /* deferOnPrepared= */ false);
            mediaPeriod.setSeekToUsOffset(10);
            return mediaPeriod;
@@ -658,14 +661,15 @@ public final class ExoPlayerTest {
              MediaPeriodId id,
              TrackGroupArray trackGroupArray,
              Allocator allocator,
+              MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
              DrmSessionManager drmSessionManager,
-              EventDispatcher eventDispatcher,
+              DrmSessionEventListener.EventDispatcher drmEventDispatcher,
              @Nullable TransferListener transferListener) {
            FakeMediaPeriod mediaPeriod =
                new FakeMediaPeriod(
                    trackGroupArray,
                    TimelineWindowDefinition.DEFAULT_WINDOW_OFFSET_IN_FIRST_PERIOD_US,
-                    eventDispatcher);
+                    mediaSourceEventDispatcher);
            mediaPeriod.setDiscontinuityPositionUs(10);
            return mediaPeriod;
          }
@@ -689,14 +693,15 @@ public final class ExoPlayerTest {
              MediaPeriodId id,
              TrackGroupArray trackGroupArray,
              Allocator allocator,
+              MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
              DrmSessionManager drmSessionManager,
-              EventDispatcher eventDispatcher,
+              DrmSessionEventListener.EventDispatcher drmEventDispatcher,
              @Nullable TransferListener transferListener) {
            FakeMediaPeriod mediaPeriod =
                new FakeMediaPeriod(
                    trackGroupArray,
                    TimelineWindowDefinition.DEFAULT_WINDOW_OFFSET_IN_FIRST_PERIOD_US,
-                    eventDispatcher);
+                    mediaSourceEventDispatcher);
            // Set a discontinuity at the position this period is supposed to start at anyway.
            mediaPeriod.setDiscontinuityPositionUs(
                timeline.getWindow(/* windowIndex= */ 0, new Window()).positionInFirstPeriodUs);
@@ -938,16 +943,18 @@ public final class ExoPlayerTest {
              MediaPeriodId id,
              TrackGroupArray trackGroupArray,
              Allocator allocator,
+              MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
              DrmSessionManager drmSessionManager,
-              EventDispatcher eventDispatcher,
+              DrmSessionEventListener.EventDispatcher drmEventDispatcher,
              @Nullable TransferListener transferListener) {
            // Defer completing preparation of the period until playback parameters have been set.
            fakeMediaPeriodHolder[0] =
                new FakeMediaPeriod(
                    trackGroupArray,
                    TimelineWindowDefinition.DEFAULT_WINDOW_OFFSET_IN_FIRST_PERIOD_US,
-                    eventDispatcher,
+                    mediaSourceEventDispatcher,
                    drmSessionManager,
+                    drmEventDispatcher,
                    /* deferOnPrepared= */ true);
            createPeriodCalledCountDownLatch.countDown();
            return fakeMediaPeriodHolder[0];
@@ -990,16 +997,18 @@ public final class ExoPlayerTest {
              MediaPeriodId id,
              TrackGroupArray trackGroupArray,
              Allocator allocator,
+              MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
              DrmSessionManager drmSessionManager,
-              EventDispatcher eventDispatcher,
+              DrmSessionEventListener.EventDispatcher drmEventDispatcher,
              @Nullable TransferListener transferListener) {
            // Defer completing preparation of the period until seek has been sent.
            fakeMediaPeriodHolder[0] =
                new FakeMediaPeriod(
                    trackGroupArray,
                    TimelineWindowDefinition.DEFAULT_WINDOW_OFFSET_IN_FIRST_PERIOD_US,
-                    eventDispatcher,
+                    mediaSourceEventDispatcher,
                    drmSessionManager,
+                    drmEventDispatcher,
                    /* deferOnPrepared= */ true);
            createPeriodCalledCountDownLatch.countDown();
            return fakeMediaPeriodHolder[0];
@@ -3723,13 +3732,14 @@ public final class ExoPlayerTest {
              MediaPeriodId id,
              TrackGroupArray trackGroupArray,
              Allocator allocator,
+              MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
              DrmSessionManager drmSessionManager,
-              EventDispatcher eventDispatcher,
+              DrmSessionEventListener.EventDispatcher drmEventDispatcher,
              @Nullable TransferListener transferListener) {
            return new FakeMediaPeriod(
                trackGroupArray,
                TimelineWindowDefinition.DEFAULT_WINDOW_OFFSET_IN_FIRST_PERIOD_US,
-                eventDispatcher) {
+                mediaSourceEventDispatcher) {
              @Override
              public long getBufferedPositionUs() {
                // Pretend not to have buffered data yet.
@@ -6365,13 +6375,14 @@ public final class ExoPlayerTest {
              MediaPeriodId id,
              TrackGroupArray trackGroupArray,
              Allocator allocator,
+              MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
              DrmSessionManager drmSessionManager,
-              EventDispatcher eventDispatcher,
+              DrmSessionEventListener.EventDispatcher drmEventDispatcher,
              @Nullable TransferListener transferListener) {
            return new FakeMediaPeriod(
                trackGroupArray,
                TimelineWindowDefinition.DEFAULT_WINDOW_OFFSET_IN_FIRST_PERIOD_US,
-                eventDispatcher) {
+                mediaSourceEventDispatcher) {
              private final List<Allocation> allocations = new ArrayList<>();
@@ -6444,14 +6455,16 @@ public final class ExoPlayerTest {
              MediaPeriodId id,
              TrackGroupArray trackGroupArray,
              Allocator allocator,
+              MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
              DrmSessionManager drmSessionManager,
-              EventDispatcher eventDispatcher,
+              DrmSessionEventListener.EventDispatcher drmEventDispatcher,
              @Nullable TransferListener transferListener) {
            return new FakeMediaPeriod(
                trackGroupArray,
                TimelineWindowDefinition.DEFAULT_WINDOW_OFFSET_IN_FIRST_PERIOD_US,
-                eventDispatcher,
+                mediaSourceEventDispatcher,
                drmSessionManager,
+                drmEventDispatcher,
                /* deferOnPrepared= */ false) {
              private Loader loader = new Loader("oomLoader");
@@ -6466,13 +6479,15 @@ public final class ExoPlayerTest {
              protected SampleStream createSampleStream(
                  long positionUs,
                  TrackSelection selection,
+                  MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
                  DrmSessionManager drmSessionManager,
-                  EventDispatcher eventDispatcher) {
+                  DrmSessionEventListener.EventDispatcher drmEventDispatcher) {
                // Create 3 samples without end of stream signal to test that all 3 samples are
                // still played before the exception is thrown.
                return new FakeSampleStream(
+                    mediaSourceEventDispatcher,
                    drmSessionManager,
-                    eventDispatcher,
+                    drmEventDispatcher,
                    selection.getSelectedFormat(),
                    ImmutableList.of(
                        oneByteSample(positionUs),

--- a/library/core/src/test/java/com/google/android/exoplayer2/audio/DecoderAudioRendererTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/audio/DecoderAudioRendererTest.java
@@ -34,6 +34,7 @@ import com.google.android.exoplayer2.decoder.DecoderException;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
 import com.google.android.exoplayer2.decoder.SimpleDecoder;
 import com.google.android.exoplayer2.decoder.SimpleOutputBuffer;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.drm.ExoMediaCrypto;
 import com.google.android.exoplayer2.testutil.FakeSampleStream;
@@ -107,8 +108,9 @@ public class DecoderAudioRendererTest {
        RendererConfiguration.DEFAULT,
        new Format[] {FORMAT},
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            FORMAT,
            ImmutableList.of(END_OF_STREAM_ITEM)),
        /* positionUs= */ 0,

--- a/library/core/src/test/java/com/google/android/exoplayer2/audio/MediaCodecAudioRendererTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/audio/MediaCodecAudioRendererTest.java
@@ -32,6 +32,7 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlaybackException;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.RendererConfiguration;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.mediacodec.MediaCodecInfo;
 import com.google.android.exoplayer2.mediacodec.MediaCodecSelector;
@@ -111,8 +112,9 @@ public class MediaCodecAudioRendererTest {
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ AUDIO_AAC,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME),
@@ -158,8 +160,9 @@ public class MediaCodecAudioRendererTest {
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ AUDIO_AAC,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME),
@@ -225,8 +228,9 @@ public class MediaCodecAudioRendererTest {
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ AUDIO_AAC,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME), END_OF_STREAM_ITEM));

--- a/library/core/src/test/java/com/google/android/exoplayer2/drm/OfflineLicenseHelperTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/drm/OfflineLicenseHelperTest.java
@@ -25,7 +25,6 @@ import android.util.Pair;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.drm.DrmInitData.SchemeData;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import java.util.HashMap;
 import org.junit.After;
 import org.junit.Before;
@@ -57,7 +56,7 @@ public class OfflineLicenseHelperTest {
            new ExoMediaDrm.AppManagedProvider(mediaDrm),
            mediaDrmCallback,
            /* optionalKeyRequestParameters= */ null,
-            new MediaSourceEventDispatcher());
+            new DrmSessionEventListener.EventDispatcher());
  }
  @After

--- a/library/core/src/test/java/com/google/android/exoplayer2/metadata/MetadataRendererTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/metadata/MetadataRendererTest.java
@@ -22,6 +22,7 @@ import static java.nio.charset.StandardCharsets.UTF_8;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.ExoPlaybackException;
 import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.metadata.emsg.EventMessage;
 import com.google.android.exoplayer2.metadata.emsg.EventMessageEncoder;
@@ -146,8 +147,9 @@ public class MetadataRendererTest {
    renderer.replaceStream(
        new Format[] {EMSG_FORMAT},
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            EMSG_FORMAT,
            ImmutableList.of(
                FakeSampleStreamItem.sample(/* timeUs= */ 0, /* flags= */ 0, input),

--- a/library/core/src/test/java/com/google/android/exoplayer2/source/ClippingMediaSourceTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/source/ClippingMediaSourceTest.java
@@ -27,11 +27,11 @@ import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.Timeline.Period;
 import com.google.android.exoplayer2.Timeline.Window;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.source.ClippingMediaSource.IllegalClippingException;
 import com.google.android.exoplayer2.source.MaskingMediaSource.DummyTimeline;
 import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
 import com.google.android.exoplayer2.testutil.FakeMediaPeriod;
 import com.google.android.exoplayer2.testutil.FakeMediaSource;
 import com.google.android.exoplayer2.testutil.FakeTimeline;
@@ -569,10 +569,11 @@ public final class ClippingMediaSourceTest {
              MediaPeriodId id,
              TrackGroupArray trackGroupArray,
              Allocator allocator,
+              MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
              DrmSessionManager drmSessionManager,
-              EventDispatcher eventDispatcher,
+              DrmSessionEventListener.EventDispatcher drmEventDispatcher,
              @Nullable TransferListener transferListener) {
-            eventDispatcher.downstreamFormatChanged(
+            mediaSourceEventDispatcher.downstreamFormatChanged(
                new MediaLoadData(
                    C.DATA_TYPE_MEDIA,
                    C.TRACK_TYPE_UNKNOWN,
@@ -585,8 +586,9 @@ public final class ClippingMediaSourceTest {
                id,
                trackGroupArray,
                allocator,
+                mediaSourceEventDispatcher,
                drmSessionManager,
-                eventDispatcher,
+                drmEventDispatcher,
                transferListener);
          }
        };

--- a/library/core/src/test/java/com/google/android/exoplayer2/source/MergingMediaPeriodTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/source/MergingMediaPeriodTest.java
@@ -24,6 +24,7 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.FormatHolder;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
 import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
@@ -200,13 +201,14 @@ public final class MergingMediaPeriodTest {
    public FakeMediaPeriodWithSelectTracksPosition(
        TrackGroupArray trackGroupArray,
-        EventDispatcher eventDispatcher,
+        EventDispatcher mediaSourceEventDispatcher,
        TrackDataFactory trackDataFactory) {
      super(
          trackGroupArray,
          trackDataFactory,
-          eventDispatcher,
+          mediaSourceEventDispatcher,
          DrmSessionManager.DUMMY,
+          new DrmSessionEventListener.EventDispatcher(),
          /* deferOnPrepared= */ false);
      selectTracksPositionUs = C.TIME_UNSET;
    }

--- a/library/core/src/test/java/com/google/android/exoplayer2/source/ProgressiveMediaPeriodTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/source/ProgressiveMediaPeriodTest.java
@@ -22,6 +22,7 @@ import android.net.Uri;
 import androidx.test.core.app.ApplicationProvider;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.extractor.Extractor;
 import com.google.android.exoplayer2.extractor.mp4.Mp4Extractor;
@@ -44,18 +45,18 @@ public final class ProgressiveMediaPeriodTest {
    AtomicBoolean sourceInfoRefreshCalled = new AtomicBoolean(false);
    ProgressiveMediaPeriod.Listener sourceInfoRefreshListener =
        (durationUs, isSeekable, isLive) -> sourceInfoRefreshCalled.set(true);
+    MediaPeriodId mediaPeriodId = new MediaPeriodId(/* periodUid= */ new Object());
    ProgressiveMediaPeriod mediaPeriod =
        new ProgressiveMediaPeriod(
            Uri.parse("asset://android_asset/mp4/sample.mp4"),
            new AssetDataSource(ApplicationProvider.getApplicationContext()),
            () -> new Extractor[] {new Mp4Extractor()},
            DrmSessionManager.DUMMY,
+            new DrmSessionEventListener.EventDispatcher()
+                .withParameters(/* windowIndex= */ 0, mediaPeriodId),
            new DefaultLoadErrorHandlingPolicy(),
            new MediaSourceEventListener.EventDispatcher()
-                .withParameters(
+                .withParameters(/* windowIndex= */ 0, mediaPeriodId, /* mediaTimeOffsetMs= */ 0),
-                    /* windowIndex= */ 0,
-                    new MediaPeriodId(/* periodUid= */ new Object()),
-                    /* mediaTimeOffsetMs= */ 0),
            sourceInfoRefreshListener,
            new DefaultAllocator(/* trimOnReset= */ true, C.DEFAULT_BUFFER_SEGMENT_SIZE),
            /* customCacheKey= */ null,

--- a/library/core/src/test/java/com/google/android/exoplayer2/source/SampleQueueTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/source/SampleQueueTest.java
@@ -35,13 +35,13 @@ import com.google.android.exoplayer2.FormatHolder;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
 import com.google.android.exoplayer2.drm.DrmInitData;
 import com.google.android.exoplayer2.drm.DrmSession;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.testutil.TestUtil;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.upstream.DefaultAllocator;
 import com.google.android.exoplayer2.util.Assertions;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.common.primitives.Bytes;
@@ -129,7 +129,7 @@ public final class SampleQueueTest {
  private Allocator allocator;
  private DrmSessionManager mockDrmSessionManager;
  private DrmSession mockDrmSession;
-  private MediaSourceEventDispatcher eventDispatcher;
+  private DrmSessionEventListener.EventDispatcher eventDispatcher;
  private SampleQueue sampleQueue;
  private FormatHolder formatHolder;
  private DecoderInputBuffer inputBuffer;
@@ -142,7 +142,7 @@ public final class SampleQueueTest {
    when(mockDrmSessionManager.acquireSession(
            ArgumentMatchers.any(), ArgumentMatchers.any(), ArgumentMatchers.any()))
        .thenReturn(mockDrmSession);
-    eventDispatcher = new MediaSourceEventDispatcher();
+    eventDispatcher = new DrmSessionEventListener.EventDispatcher();
    sampleQueue =
        new SampleQueue(
            allocator,

--- a/library/core/src/test/java/com/google/android/exoplayer2/util/MediaSourceEventDispatcherTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/util/MediaSourceEventDispatcherTest.java
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-package com.google.android.exoplayer2.util;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.ArgumentMatchers.anyInt;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.never;
-import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.verifyNoMoreInteractions;
-import android.os.Handler;
-import android.os.Looper;
-import androidx.annotation.Nullable;
-import androidx.test.ext.junit.runners.AndroidJUnit4;
-import com.google.android.exoplayer2.drm.DrmSessionEventListener;
-import com.google.android.exoplayer2.source.MediaSource;
-import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
-import com.google.android.exoplayer2.source.MediaSourceEventListener;
-import org.junit.Before;
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.mockito.Mock;
-import org.mockito.junit.MockitoJUnit;
-import org.mockito.junit.MockitoRule;
-/** Tests for {@link MediaSourceEventDispatcher}. */
-@RunWith(AndroidJUnit4.class)
-public class MediaSourceEventDispatcherTest {
-  private static final MediaSource.MediaPeriodId MEDIA_PERIOD_ID =
-      new MediaSource.MediaPeriodId("test uid");
-  private static final int WINDOW_INDEX = 200;
-  private static final int MEDIA_TIME_OFFSET_MS = 1_000;
-  @Rule public final MockitoRule mockito = MockitoJUnit.rule();
-  @Mock private MediaSourceEventListener mediaSourceEventListener;
-  @Mock private MediaAndDrmEventListener mediaAndDrmEventListener;
-  private MediaSourceEventDispatcher eventDispatcher;
-  @Before
-  public void setupEventDispatcher() {
-    eventDispatcher = new MediaSourceEventDispatcher();
-    eventDispatcher =
-        eventDispatcher.withParameters(WINDOW_INDEX, MEDIA_PERIOD_ID, MEDIA_TIME_OFFSET_MS);
-  }
-  @Test
-  public void listenerReceivesEventPopulatedWithMediaPeriodInfo() {
-    eventDispatcher.addEventListener(
-        Util.createHandlerForCurrentOrMainLooper(),
-        mediaSourceEventListener,
-        MediaSourceEventListener.class);
-    eventDispatcher.dispatch(
-        MediaSourceEventListener::onMediaPeriodCreated, MediaSourceEventListener.class);
-    verify(mediaSourceEventListener).onMediaPeriodCreated(WINDOW_INDEX, MEDIA_PERIOD_ID);
-  }
-  @Test
-  public void sameListenerObjectRegisteredTwiceOnlyReceivesEventsOnce() {
-    eventDispatcher.addEventListener(
-        Util.createHandlerForCurrentOrMainLooper(),
-        mediaSourceEventListener,
-        MediaSourceEventListener.class);
-    eventDispatcher.addEventListener(
-        Util.createHandlerForCurrentOrMainLooper(),
-        mediaSourceEventListener,
-        MediaSourceEventListener.class);
-    eventDispatcher.dispatch(
-        MediaSourceEventListener::onMediaPeriodCreated, MediaSourceEventListener.class);
-    verify(mediaSourceEventListener).onMediaPeriodCreated(WINDOW_INDEX, MEDIA_PERIOD_ID);
-  }
-  @Test
-  public void sameListenerInstanceCanBeRegisteredWithTwoTypes() {
-    eventDispatcher.addEventListener(
-        new Handler(Looper.getMainLooper()),
-        mediaAndDrmEventListener,
-        MediaSourceEventListener.class);
-    eventDispatcher.addEventListener(
-        new Handler(Looper.getMainLooper()),
-        mediaAndDrmEventListener,
-        DrmSessionEventListener.class);
-    eventDispatcher.dispatch(
-        MediaSourceEventListener::onMediaPeriodCreated, MediaSourceEventListener.class);
-    eventDispatcher.dispatch(
-        DrmSessionEventListener::onDrmKeysLoaded, DrmSessionEventListener.class);
-    verify(mediaAndDrmEventListener).onMediaPeriodCreated(WINDOW_INDEX, MEDIA_PERIOD_ID);
-    verify(mediaAndDrmEventListener).onDrmKeysLoaded(WINDOW_INDEX, MEDIA_PERIOD_ID);
-  }
-  // If a listener is added that implements multiple types, it should only receive events for the
-  // type specified at registration time.
-  @Test
-  public void listenerOnlyReceivesEventsForRegisteredType() {
-    eventDispatcher.addEventListener(
-        new Handler(Looper.getMainLooper()),
-        mediaAndDrmEventListener,
-        MediaSourceEventListener.class);
-    eventDispatcher.dispatch(
-        MediaSourceEventListener::onMediaPeriodCreated, MediaSourceEventListener.class);
-    eventDispatcher.dispatch(
-        DrmSessionEventListener::onDrmKeysLoaded, DrmSessionEventListener.class);
-    verify(mediaAndDrmEventListener).onMediaPeriodCreated(WINDOW_INDEX, MEDIA_PERIOD_ID);
-    verify(mediaAndDrmEventListener, never()).onDrmKeysLoaded(WINDOW_INDEX, MEDIA_PERIOD_ID);
-  }
-  @Test
-  public void listenerDoesntReceiveEventsDispatchedToSubclass() {
-    SubclassListener subclassListener = mock(SubclassListener.class);
-    eventDispatcher.addEventListener(
-        new Handler(Looper.getMainLooper()), subclassListener, MediaSourceEventListener.class);
-    eventDispatcher.dispatch(SubclassListener::subclassMethod, SubclassListener.class);
-    // subclassListener can handle the call to subclassMethod, but it isn't called because
-    // it was registered 'as-a' MediaSourceEventListener, not SubclassListener.
-    verify(subclassListener, never()).subclassMethod(anyInt(), any());
-  }
-  @Test
-  public void listenerDoesntReceiveEventsDispatchedToSuperclass() {
-    SubclassListener subclassListener = mock(SubclassListener.class);
-    eventDispatcher.addEventListener(
-        new Handler(Looper.getMainLooper()), subclassListener, SubclassListener.class);
-    eventDispatcher.dispatch(
-        MediaSourceEventListener::onMediaPeriodCreated, MediaSourceEventListener.class);
-    // subclassListener 'is-a' a MediaSourceEventListener, but it isn't called because the event
-    // is dispatched specifically to listeners registered as MediaSourceEventListener.
-    verify(subclassListener, never()).onMediaPeriodCreated(anyInt(), any());
-  }
-  @Test
-  public void listenersAreCopiedToNewDispatcher() {
-    eventDispatcher.addEventListener(
-        Util.createHandlerForCurrentOrMainLooper(),
-        mediaSourceEventListener,
-        MediaSourceEventListener.class);
-    MediaSource.MediaPeriodId newPeriodId = new MediaSource.MediaPeriodId("different uid");
-    MediaSourceEventDispatcher newEventDispatcher =
-        this.eventDispatcher.withParameters(
-            /* windowIndex= */ 250, newPeriodId, /* mediaTimeOffsetMs= */ 500);
-    newEventDispatcher.dispatch(
-        MediaSourceEventListener::onMediaPeriodCreated, MediaSourceEventListener.class);
-    verify(mediaSourceEventListener).onMediaPeriodCreated(250, newPeriodId);
-  }
-  @Test
-  public void removingListenerStopsEventDispatch() {
-    eventDispatcher.addEventListener(
-        Util.createHandlerForCurrentOrMainLooper(),
-        mediaSourceEventListener,
-        MediaSourceEventListener.class);
-    eventDispatcher.removeEventListener(mediaSourceEventListener, MediaSourceEventListener.class);
-    eventDispatcher.dispatch(
-        MediaSourceEventListener::onMediaPeriodCreated, MediaSourceEventListener.class);
-    verify(mediaSourceEventListener, never()).onMediaPeriodCreated(anyInt(), any());
-  }
-  @Test
-  public void removingListenerWithDifferentTypeToRegistrationDoesntRemove() {
-    eventDispatcher.addEventListener(
-        Util.createHandlerForCurrentOrMainLooper(),
-        mediaAndDrmEventListener,
-        MediaSourceEventListener.class);
-    eventDispatcher.removeEventListener(mediaAndDrmEventListener, DrmSessionEventListener.class);
-    eventDispatcher.dispatch(
-        MediaSourceEventListener::onMediaPeriodCreated, MediaSourceEventListener.class);
-    verify(mediaAndDrmEventListener).onMediaPeriodCreated(WINDOW_INDEX, MEDIA_PERIOD_ID);
-  }
-  @Test
-  public void listenersAreCountedBasedOnListenerAndType() {
-    // Add the listener twice and remove it once.
-    eventDispatcher.addEventListener(
-        Util.createHandlerForCurrentOrMainLooper(),
-        mediaSourceEventListener,
-        MediaSourceEventListener.class);
-    eventDispatcher.addEventListener(
-        Util.createHandlerForCurrentOrMainLooper(),
-        mediaSourceEventListener,
-        MediaSourceEventListener.class);
-    eventDispatcher.removeEventListener(mediaSourceEventListener, MediaSourceEventListener.class);
-    eventDispatcher.dispatch(
-        MediaSourceEventListener::onMediaPeriodCreated, MediaSourceEventListener.class);
-    verify(mediaSourceEventListener).onMediaPeriodCreated(WINDOW_INDEX, MEDIA_PERIOD_ID);
-    // Remove it a second time and confirm the events stop being propagated.
-    eventDispatcher.removeEventListener(mediaSourceEventListener, MediaSourceEventListener.class);
-    verifyNoMoreInteractions(mediaSourceEventListener);
-  }
-  private interface MediaAndDrmEventListener
-      extends MediaSourceEventListener, DrmSessionEventListener {}
-  private interface SubclassListener extends MediaSourceEventListener {
-    void subclassMethod(int windowIndex, @Nullable MediaPeriodId mediaPeriodId);
-  }
-}
--- a/library/core/src/test/java/com/google/android/exoplayer2/video/DecoderVideoRendererTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/video/DecoderVideoRendererTest.java
@@ -35,6 +35,7 @@ import com.google.android.exoplayer2.RendererConfiguration;
 import com.google.android.exoplayer2.decoder.DecoderException;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
 import com.google.android.exoplayer2.decoder.SimpleDecoder;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.drm.ExoMediaCrypto;
 import com.google.android.exoplayer2.testutil.FakeSampleStream;
@@ -185,8 +186,9 @@ public final class DecoderVideoRendererTest {
  public void enable_withMayRenderStartOfStream_rendersFirstFrameBeforeStart() throws Exception {
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ H264_FORMAT,
            ImmutableList.of(oneByteSample(/* timeUs= */ 0)));
@@ -212,8 +214,9 @@ public final class DecoderVideoRendererTest {
      throws Exception {
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ H264_FORMAT,
            ImmutableList.of(oneByteSample(/* timeUs= */ 0)));
@@ -238,8 +241,9 @@ public final class DecoderVideoRendererTest {
  public void enable_withoutMayRenderStartOfStream_rendersFirstFrameAfterStart() throws Exception {
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ H264_FORMAT,
            ImmutableList.of(oneByteSample(/* timeUs= */ 0)));
@@ -267,15 +271,17 @@ public final class DecoderVideoRendererTest {
  public void replaceStream_whenStarted_rendersFirstFrameOfNewStream() throws Exception {
    FakeSampleStream fakeSampleStream1 =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ H264_FORMAT,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0), FakeSampleStreamItem.END_OF_STREAM_ITEM));
    FakeSampleStream fakeSampleStream2 =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ H264_FORMAT,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0), FakeSampleStreamItem.END_OF_STREAM_ITEM));
@@ -309,15 +315,17 @@ public final class DecoderVideoRendererTest {
  public void replaceStream_whenNotStarted_doesNotRenderFirstFrameOfNewStream() throws Exception {
    FakeSampleStream fakeSampleStream1 =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ H264_FORMAT,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0), FakeSampleStreamItem.END_OF_STREAM_ITEM));
    FakeSampleStream fakeSampleStream2 =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ H264_FORMAT,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0), FakeSampleStreamItem.END_OF_STREAM_ITEM));

--- a/library/core/src/test/java/com/google/android/exoplayer2/video/MediaCodecVideoRendererTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/video/MediaCodecVideoRendererTest.java
@@ -40,6 +40,7 @@ import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.Renderer;
 import com.google.android.exoplayer2.RendererCapabilities;
 import com.google.android.exoplayer2.RendererConfiguration;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.mediacodec.MediaCodecInfo;
 import com.google.android.exoplayer2.mediacodec.MediaCodecSelector;
@@ -129,8 +130,9 @@ public class MediaCodecVideoRendererTest {
  public void render_dropsLateBuffer() throws Exception {
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ VIDEO_H264,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME), // First buffer.
@@ -165,8 +167,9 @@ public class MediaCodecVideoRendererTest {
        RendererConfiguration.DEFAULT,
        new Format[] {VIDEO_H264},
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ VIDEO_H264,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME),
@@ -202,8 +205,9 @@ public class MediaCodecVideoRendererTest {
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ pAsp1,
            ImmutableList.of(oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME)));
@@ -246,8 +250,9 @@ public class MediaCodecVideoRendererTest {
      throws Exception {
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ VIDEO_H264,
            ImmutableList.of(oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME)));
    mediaCodecVideoRenderer.enable(
@@ -279,8 +284,9 @@ public class MediaCodecVideoRendererTest {
  public void enable_withMayRenderStartOfStream_rendersFirstFrameBeforeStart() throws Exception {
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ VIDEO_H264,
            ImmutableList.of(oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME)));
@@ -304,8 +310,9 @@ public class MediaCodecVideoRendererTest {
      throws Exception {
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ VIDEO_H264,
            ImmutableList.of(oneByteSample(/* timeUs= */ 0)));
@@ -328,8 +335,9 @@ public class MediaCodecVideoRendererTest {
  public void enable_withoutMayRenderStartOfStream_rendersFirstFrameAfterStart() throws Exception {
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ VIDEO_H264,
            ImmutableList.of(oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME)));
@@ -353,16 +361,18 @@ public class MediaCodecVideoRendererTest {
  public void replaceStream_whenStarted_rendersFirstFrameOfNewStream() throws Exception {
    FakeSampleStream fakeSampleStream1 =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ VIDEO_H264,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME),
                FakeSampleStreamItem.END_OF_STREAM_ITEM));
    FakeSampleStream fakeSampleStream2 =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ VIDEO_H264,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME),
@@ -395,16 +405,18 @@ public class MediaCodecVideoRendererTest {
  public void replaceStream_whenNotStarted_doesNotRenderFirstFrameOfNewStream() throws Exception {
    FakeSampleStream fakeSampleStream1 =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ VIDEO_H264,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME),
                FakeSampleStreamItem.END_OF_STREAM_ITEM));
    FakeSampleStream fakeSampleStream2 =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ VIDEO_H264,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME),
@@ -443,8 +455,9 @@ public class MediaCodecVideoRendererTest {
    Format mp4Uhd = VIDEO_H264.buildUpon().setWidth(3840).setHeight(2160).build();
    FakeSampleStream fakeSampleStream =
        new FakeSampleStream(
+            /* mediaSourceEventDispatcher= */ null,
            DrmSessionManager.DUMMY,
-            /* eventDispatcher= */ null,
+            new DrmSessionEventListener.EventDispatcher(),
            /* initialFormat= */ mp4Uhd,
            ImmutableList.of(
                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME),

--- a/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaPeriod.java
+++ b/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaPeriod.java
@@ -24,11 +24,13 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.SeekParameters;
 import com.google.android.exoplayer2.drm.DrmInitData;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.offline.StreamKey;
 import com.google.android.exoplayer2.source.CompositeSequenceableLoaderFactory;
 import com.google.android.exoplayer2.source.EmptySampleStream;
 import com.google.android.exoplayer2.source.MediaPeriod;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
 import com.google.android.exoplayer2.source.SampleStream;
 import com.google.android.exoplayer2.source.SequenceableLoader;
@@ -90,7 +92,8 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
  private final PlayerEmsgHandler playerEmsgHandler;
  private final IdentityHashMap<ChunkSampleStream<DashChunkSource>, PlayerTrackEmsgHandler>
      trackEmsgHandlerBySampleStream;
-  private final EventDispatcher eventDispatcher;
+  private final MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher;
+  private final DrmSessionEventListener.EventDispatcher drmEventDispatcher;
  @Nullable private Callback callback;
  private ChunkSampleStream<DashChunkSource>[] sampleStreams;
@@ -108,8 +111,9 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
      DashChunkSource.Factory chunkSourceFactory,
      @Nullable TransferListener transferListener,
      DrmSessionManager drmSessionManager,
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher,
      LoadErrorHandlingPolicy loadErrorHandlingPolicy,
-      EventDispatcher eventDispatcher,
+      EventDispatcher mediaSourceEventDispatcher,
      long elapsedRealtimeOffsetMs,
      LoaderErrorThrower manifestLoaderErrorThrower,
      Allocator allocator,
@@ -121,8 +125,9 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
    this.chunkSourceFactory = chunkSourceFactory;
    this.transferListener = transferListener;
    this.drmSessionManager = drmSessionManager;
+    this.drmEventDispatcher = drmEventDispatcher;
    this.loadErrorHandlingPolicy = loadErrorHandlingPolicy;
-    this.eventDispatcher = eventDispatcher;
+    this.mediaSourceEventDispatcher = mediaSourceEventDispatcher;
    this.elapsedRealtimeOffsetMs = elapsedRealtimeOffsetMs;
    this.manifestLoaderErrorThrower = manifestLoaderErrorThrower;
    this.allocator = allocator;
@@ -139,7 +144,7 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
        buildTrackGroups(drmSessionManager, period.adaptationSets, eventStreams);
    trackGroups = result.first;
    trackGroupInfos = result.second;
-    eventDispatcher.mediaPeriodCreated();
+    mediaSourceEventDispatcher.mediaPeriodCreated();
  }
  /**
@@ -178,7 +183,7 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
      sampleStream.release(this);
    }
    callback = null;
-    eventDispatcher.mediaPeriodReleased();
+    mediaSourceEventDispatcher.mediaPeriodReleased();
  }
  // ChunkSampleStream.ReleaseCallback implementation.
@@ -316,7 +321,7 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
  @Override
  public long readDiscontinuity() {
    if (!notifiedReadingStarted) {
-      eventDispatcher.readingStarted();
+      mediaSourceEventDispatcher.readingStarted();
      notifiedReadingStarted = true;
    }
    return C.TIME_UNSET;
@@ -788,8 +793,9 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
            allocator,
            positionUs,
            drmSessionManager,
+            drmEventDispatcher,
            loadErrorHandlingPolicy,
-            eventDispatcher);
+            mediaSourceEventDispatcher);
    synchronized (this) {
      // The map is also accessed on the loading thread so synchronize access.
      trackEmsgHandlerBySampleStream.put(stream, trackPlayerEmsgHandler);

--- a/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaSource.java
+++ b/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaSource.java
@@ -29,6 +29,7 @@ import com.google.android.exoplayer2.MediaItem;
 import com.google.android.exoplayer2.ParserException;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.drm.DrmSession;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.offline.FilteringManifestParser;
 import com.google.android.exoplayer2.offline.StreamKey;
@@ -694,8 +695,9 @@ public final class DashMediaSource extends BaseMediaSource {
  public MediaPeriod createPeriod(
      MediaPeriodId periodId, Allocator allocator, long startPositionUs) {
    int periodIndex = (Integer) periodId.periodUid - firstPeriodId;
-    EventDispatcher periodEventDispatcher =
+    MediaSourceEventListener.EventDispatcher periodEventDispatcher =
        createEventDispatcher(periodId, manifest.getPeriod(periodIndex).startMs);
+    DrmSessionEventListener.EventDispatcher drmEventDispatcher = createDrmEventDispatcher(periodId);
    DashMediaPeriod mediaPeriod =
        new DashMediaPeriod(
            firstPeriodId + periodIndex,
@@ -704,6 +706,7 @@ public final class DashMediaSource extends BaseMediaSource {
            chunkSourceFactory,
            mediaTransferListener,
            drmSessionManager,
+            drmEventDispatcher,
            loadErrorHandlingPolicy,
            periodEventDispatcher,
            elapsedRealtimeOffsetMs,

--- a/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/PlayerEmsgHandler.java
+++ b/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/PlayerEmsgHandler.java
@@ -24,6 +24,7 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.FormatHolder;
 import com.google.android.exoplayer2.ParserException;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.metadata.Metadata;
@@ -35,7 +36,6 @@ import com.google.android.exoplayer2.source.chunk.Chunk;
 import com.google.android.exoplayer2.source.dash.manifest.DashManifest;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.upstream.DataReader;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.Util;
 import java.io.IOException;
@@ -290,7 +290,7 @@ public final class PlayerEmsgHandler implements Handler.Callback {
              allocator,
              /* playbackLooper= */ handler.getLooper(),
              DrmSessionManager.getDummyDrmSessionManager(),
-              new MediaSourceEventDispatcher());
+              new DrmSessionEventListener.EventDispatcher());
      formatHolder = new FormatHolder();
      buffer = new MetadataInputBuffer();
    }

--- a/library/dash/src/test/java/com/google/android/exoplayer2/source/dash/DashMediaPeriodTest.java
+++ b/library/dash/src/test/java/com/google/android/exoplayer2/source/dash/DashMediaPeriodTest.java
@@ -22,10 +22,11 @@ import androidx.annotation.Nullable;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.source.CompositeSequenceableLoaderFactory;
 import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.source.dash.PlayerEmsgHandler.PlayerEmsgCallback;
@@ -344,6 +345,7 @@ public final class DashMediaPeriodTest {
  }
  private static DashMediaPeriod createDashMediaPeriod(DashManifest manifest, int periodIndex) {
+    MediaPeriodId mediaPeriodId = new MediaPeriodId(/* periodUid= */ new Object());
    return new DashMediaPeriod(
        /* id= */ periodIndex,
        manifest,
@@ -351,12 +353,11 @@ public final class DashMediaPeriodTest {
        mock(DashChunkSource.Factory.class),
        mock(TransferListener.class),
        DrmSessionManager.getDummyDrmSessionManager(),
+        new DrmSessionEventListener.EventDispatcher()
+            .withParameters(/* windowIndex= */ 0, mediaPeriodId),
        mock(LoadErrorHandlingPolicy.class),
-        new EventDispatcher()
+        new MediaSourceEventListener.EventDispatcher()
-            .withParameters(
+            .withParameters(/* windowIndex= */ 0, mediaPeriodId, /* mediaTimeOffsetMs= */ 0),
-                /* windowIndex= */ 0,
-                /* mediaPeriodId= */ new MediaPeriodId(/* periodUid= */ new Object()),
-                /* mediaTimeOffsetMs= */ 0),
        /* elapsedRealtimeOffsetMs= */ 0,
        mock(LoaderErrorThrower.class),
        mock(Allocator.class),

--- a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaPeriod.java
+++ b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaPeriod.java
@@ -23,6 +23,7 @@ import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.SeekParameters;
 import com.google.android.exoplayer2.drm.DrmInitData;
 import com.google.android.exoplayer2.drm.DrmSession;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.extractor.Extractor;
 import com.google.android.exoplayer2.metadata.Metadata;
@@ -69,6 +70,7 @@ public final class HlsMediaPeriod implements MediaPeriod, HlsSampleStreamWrapper
  private final HlsDataSourceFactory dataSourceFactory;
  @Nullable private final TransferListener mediaTransferListener;
  private final DrmSessionManager drmSessionManager;
+  private final DrmSessionEventListener.EventDispatcher drmEventDispatcher;
  private final LoadErrorHandlingPolicy loadErrorHandlingPolicy;
  private final EventDispatcher eventDispatcher;
  private final Allocator allocator;
@@ -114,6 +116,7 @@ public final class HlsMediaPeriod implements MediaPeriod, HlsSampleStreamWrapper
      HlsDataSourceFactory dataSourceFactory,
      @Nullable TransferListener mediaTransferListener,
      DrmSessionManager drmSessionManager,
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher,
      LoadErrorHandlingPolicy loadErrorHandlingPolicy,
      EventDispatcher eventDispatcher,
      Allocator allocator,
@@ -126,6 +129,7 @@ public final class HlsMediaPeriod implements MediaPeriod, HlsSampleStreamWrapper
    this.dataSourceFactory = dataSourceFactory;
    this.mediaTransferListener = mediaTransferListener;
    this.drmSessionManager = drmSessionManager;
+    this.drmEventDispatcher = drmEventDispatcher;
    this.loadErrorHandlingPolicy = loadErrorHandlingPolicy;
    this.eventDispatcher = eventDispatcher;
    this.allocator = allocator;
@@ -758,6 +762,7 @@ public final class HlsMediaPeriod implements MediaPeriod, HlsSampleStreamWrapper
        positionUs,
        muxedAudioFormat,
        drmSessionManager,
+        drmEventDispatcher,
        loadErrorHandlingPolicy,
        eventDispatcher,
        metadataType);

--- a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaSource.java
+++ b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaSource.java
@@ -26,6 +26,7 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlayerLibraryInfo;
 import com.google.android.exoplayer2.MediaItem;
 import com.google.android.exoplayer2.drm.DrmSession;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.extractor.Extractor;
 import com.google.android.exoplayer2.offline.StreamKey;
@@ -35,7 +36,6 @@ import com.google.android.exoplayer2.source.DefaultCompositeSequenceableLoaderFa
 import com.google.android.exoplayer2.source.MediaPeriod;
 import com.google.android.exoplayer2.source.MediaSource;
 import com.google.android.exoplayer2.source.MediaSourceEventListener;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
 import com.google.android.exoplayer2.source.MediaSourceFactory;
 import com.google.android.exoplayer2.source.SequenceableLoader;
 import com.google.android.exoplayer2.source.SinglePeriodTimeline;
@@ -446,7 +446,8 @@ public final class HlsMediaSource extends BaseMediaSource
  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
    this.mediaTransferListener = mediaTransferListener;
    drmSessionManager.prepare();
-    EventDispatcher eventDispatcher = createEventDispatcher(/* mediaPeriodId= */ null);
+    MediaSourceEventListener.EventDispatcher eventDispatcher =
+        createEventDispatcher(/* mediaPeriodId= */ null);
    playlistTracker.start(playbackProperties.uri, eventDispatcher, /* listener= */ this);
  }
@@ -457,15 +458,17 @@ public final class HlsMediaSource extends BaseMediaSource
  @Override
  public MediaPeriod createPeriod(MediaPeriodId id, Allocator allocator, long startPositionUs) {
-    EventDispatcher eventDispatcher = createEventDispatcher(id);
+    MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher = createEventDispatcher(id);
+    DrmSessionEventListener.EventDispatcher drmEventDispatcher = createDrmEventDispatcher(id);
    return new HlsMediaPeriod(
        extractorFactory,
        playlistTracker,
        dataSourceFactory,
        mediaTransferListener,
        drmSessionManager,
+        drmEventDispatcher,
        loadErrorHandlingPolicy,
-        eventDispatcher,
+        mediaSourceEventDispatcher,
        allocator,
        compositeSequenceableLoaderFactory,
        allowChunklessPreparation,

--- a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsSampleStreamWrapper.java
+++ b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsSampleStreamWrapper.java
@@ -27,6 +27,7 @@ import com.google.android.exoplayer2.ParserException;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
 import com.google.android.exoplayer2.drm.DrmInitData;
 import com.google.android.exoplayer2.drm.DrmSession;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.extractor.DummyTrackOutput;
 import com.google.android.exoplayer2.extractor.Extractor;
@@ -39,7 +40,7 @@ import com.google.android.exoplayer2.metadata.emsg.EventMessageDecoder;
 import com.google.android.exoplayer2.metadata.id3.PrivFrame;
 import com.google.android.exoplayer2.source.LoadEventInfo;
 import com.google.android.exoplayer2.source.MediaLoadData;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.SampleQueue;
 import com.google.android.exoplayer2.source.SampleQueue.UpstreamFormatChangedListener;
 import com.google.android.exoplayer2.source.SampleStream;
@@ -57,7 +58,6 @@ import com.google.android.exoplayer2.upstream.Loader;
 import com.google.android.exoplayer2.upstream.Loader.LoadErrorAction;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Log;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.Util;
@@ -120,9 +120,10 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
  private final Allocator allocator;
  @Nullable private final Format muxedAudioFormat;
  private final DrmSessionManager drmSessionManager;
+  private final DrmSessionEventListener.EventDispatcher drmEventDispatcher;
  private final LoadErrorHandlingPolicy loadErrorHandlingPolicy;
  private final Loader loader;
-  private final EventDispatcher eventDispatcher;
+  private final MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher;
  private final @HlsMediaSource.MetadataType int metadataType;
  private final HlsChunkSource.HlsChunkHolder nextChunkHolder;
  private final ArrayList<HlsMediaChunk> mediaChunks;
@@ -185,8 +186,10 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
   * @param muxedAudioFormat Optional muxed audio {@link Format} as defined by the master playlist.
   * @param drmSessionManager The {@link DrmSessionManager} to acquire {@link DrmSession
   *     DrmSessions} with.
+   * @param drmEventDispatcher A dispatcher to notify of {@link DrmSessionEventListener} events.
   * @param loadErrorHandlingPolicy A {@link LoadErrorHandlingPolicy}.
-   * @param eventDispatcher A dispatcher to notify of events.
+   * @param mediaSourceEventDispatcher A dispatcher to notify of {@link MediaSourceEventListener}
+   *     events.
   */
  public HlsSampleStreamWrapper(
      int trackType,
@@ -197,8 +200,9 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
      long positionUs,
      @Nullable Format muxedAudioFormat,
      DrmSessionManager drmSessionManager,
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher,
      LoadErrorHandlingPolicy loadErrorHandlingPolicy,
-      EventDispatcher eventDispatcher,
+      MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
      @HlsMediaSource.MetadataType int metadataType) {
    this.trackType = trackType;
    this.callback = callback;
@@ -207,8 +211,9 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
    this.allocator = allocator;
    this.muxedAudioFormat = muxedAudioFormat;
    this.drmSessionManager = drmSessionManager;
+    this.drmEventDispatcher = drmEventDispatcher;
    this.loadErrorHandlingPolicy = loadErrorHandlingPolicy;
-    this.eventDispatcher = eventDispatcher;
+    this.mediaSourceEventDispatcher = mediaSourceEventDispatcher;
    this.metadataType = metadataType;
    loader = new Loader("Loader:HlsSampleStreamWrapper");
    nextChunkHolder = new HlsChunkSource.HlsChunkHolder();
@@ -552,8 +557,11 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
      HlsMediaChunk currentChunk = mediaChunks.get(0);
      Format trackFormat = currentChunk.trackFormat;
      if (!trackFormat.equals(downstreamTrackFormat)) {
-        eventDispatcher.downstreamFormatChanged(trackType, trackFormat,
+        mediaSourceEventDispatcher.downstreamFormatChanged(
-            currentChunk.trackSelectionReason, currentChunk.trackSelectionData,
+            trackType,
+            trackFormat,
+            currentChunk.trackSelectionReason,
+            currentChunk.trackSelectionData,
            currentChunk.startTimeUs);
      }
      downstreamTrackFormat = trackFormat;
@@ -682,7 +690,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
    long elapsedRealtimeMs =
        loader.startLoading(
            loadable, this, loadErrorHandlingPolicy.getMinimumLoadableRetryCount(loadable.type));
-    eventDispatcher.loadStarted(
+    mediaSourceEventDispatcher.loadStarted(
        new LoadEventInfo(loadable.loadTaskId, loadable.dataSpec, elapsedRealtimeMs),
        loadable.type,
        trackType,
@@ -735,7 +743,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
            loadDurationMs,
            loadable.bytesLoaded());
    loadErrorHandlingPolicy.onLoadTaskConcluded(loadable.loadTaskId);
-    eventDispatcher.loadCompleted(
+    mediaSourceEventDispatcher.loadCompleted(
        loadEventInfo,
        loadable.type,
        trackType,
@@ -765,7 +773,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
            loadDurationMs,
            loadable.bytesLoaded());
    loadErrorHandlingPolicy.onLoadTaskConcluded(loadable.loadTaskId);
-    eventDispatcher.loadCanceled(
+    mediaSourceEventDispatcher.loadCanceled(
        loadEventInfo,
        loadable.type,
        trackType,
@@ -838,7 +846,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
    }
    boolean wasCanceled = !loadErrorAction.isRetry();
-    eventDispatcher.loadError(
+    mediaSourceEventDispatcher.loadError(
        loadEventInfo,
        loadable.type,
        trackType,
@@ -910,7 +918,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
    }
    loadingFinished = false;
-    eventDispatcher.upstreamDiscarded(
+    mediaSourceEventDispatcher.upstreamDiscarded(
        primarySampleQueueType, firstRemovedChunk.startTimeUs, endTimeUs);
  }
@@ -989,7 +997,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
            allocator,
            /* playbackLooper= */ handler.getLooper(),
            drmSessionManager,
-            eventDispatcher,
+            drmEventDispatcher,
            overridingDrmInitData);
    if (isAudioVideo) {
      sampleQueue.setDrmInitData(drmInitData);
@@ -1496,7 +1504,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
        Allocator allocator,
        Looper playbackLooper,
        DrmSessionManager drmSessionManager,
-        MediaSourceEventDispatcher eventDispatcher,
+        DrmSessionEventListener.EventDispatcher eventDispatcher,
        Map<String, DrmInitData> overridingDrmInitData) {
      super(allocator, playbackLooper, drmSessionManager, eventDispatcher);
      this.overridingDrmInitData = overridingDrmInitData;

--- a/library/hls/src/test/java/com/google/android/exoplayer2/source/hls/HlsMediaPeriodTest.java
+++ b/library/hls/src/test/java/com/google/android/exoplayer2/source/hls/HlsMediaPeriodTest.java
@@ -22,10 +22,11 @@ import static org.mockito.Mockito.when;
 import android.net.Uri;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.source.CompositeSequenceableLoaderFactory;
 import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.hls.playlist.HlsMasterPlaylist;
 import com.google.android.exoplayer2.source.hls.playlist.HlsMasterPlaylist.Rendition;
 import com.google.android.exoplayer2.source.hls.playlist.HlsMasterPlaylist.Variant;
@@ -77,18 +78,18 @@ public final class HlsMediaPeriodTest {
          when(mockDataSourceFactory.createDataSource(anyInt())).thenReturn(mock(DataSource.class));
          HlsPlaylistTracker mockPlaylistTracker = mock(HlsPlaylistTracker.class);
          when(mockPlaylistTracker.getMasterPlaylist()).thenReturn((HlsMasterPlaylist) playlist);
+          MediaPeriodId mediaPeriodId = new MediaPeriodId(/* periodUid= */ new Object());
          return new HlsMediaPeriod(
              mock(HlsExtractorFactory.class),
              mockPlaylistTracker,
              mockDataSourceFactory,
              mock(TransferListener.class),
              mock(DrmSessionManager.class),
+              new DrmSessionEventListener.EventDispatcher()
+                  .withParameters(/* windowIndex= */ 0, mediaPeriodId),
              mock(LoadErrorHandlingPolicy.class),
-              new EventDispatcher()
+              new MediaSourceEventListener.EventDispatcher()
-                  .withParameters(
+                  .withParameters(/* windowIndex= */ 0, mediaPeriodId, /* mediaTimeOffsetMs= */ 0),
-                      /* windowIndex= */ 0,
-                      /* mediaPeriodId= */ new MediaPeriodId(/* periodUid= */ new Object()),
-                      /* mediaTimeOffsetMs= */ 0),
              mock(Allocator.class),
              mock(CompositeSequenceableLoaderFactory.class),
              /* allowChunklessPreparation =*/ true,

--- a/library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaPeriod.java
+++ b/library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaPeriod.java
@@ -19,11 +19,12 @@ import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.SeekParameters;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.offline.StreamKey;
 import com.google.android.exoplayer2.source.CompositeSequenceableLoaderFactory;
 import com.google.android.exoplayer2.source.MediaPeriod;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.SampleStream;
 import com.google.android.exoplayer2.source.SequenceableLoader;
 import com.google.android.exoplayer2.source.TrackGroup;
@@ -48,8 +49,9 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
  @Nullable private final TransferListener transferListener;
  private final LoaderErrorThrower manifestLoaderErrorThrower;
  private final DrmSessionManager drmSessionManager;
+  private final DrmSessionEventListener.EventDispatcher drmEventDispatcher;
  private final LoadErrorHandlingPolicy loadErrorHandlingPolicy;
-  private final EventDispatcher eventDispatcher;
+  private final MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher;
  private final Allocator allocator;
  private final TrackGroupArray trackGroups;
  private final CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory;
@@ -66,8 +68,9 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
      @Nullable TransferListener transferListener,
      CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory,
      DrmSessionManager drmSessionManager,
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher,
      LoadErrorHandlingPolicy loadErrorHandlingPolicy,
-      EventDispatcher eventDispatcher,
+      MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
      LoaderErrorThrower manifestLoaderErrorThrower,
      Allocator allocator) {
    this.manifest = manifest;
@@ -75,15 +78,16 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
    this.transferListener = transferListener;
    this.manifestLoaderErrorThrower = manifestLoaderErrorThrower;
    this.drmSessionManager = drmSessionManager;
+    this.drmEventDispatcher = drmEventDispatcher;
    this.loadErrorHandlingPolicy = loadErrorHandlingPolicy;
-    this.eventDispatcher = eventDispatcher;
+    this.mediaSourceEventDispatcher = mediaSourceEventDispatcher;
    this.allocator = allocator;
    this.compositeSequenceableLoaderFactory = compositeSequenceableLoaderFactory;
    trackGroups = buildTrackGroups(manifest, drmSessionManager);
    sampleStreams = newSampleStreamArray(0);
    compositeSequenceableLoader =
        compositeSequenceableLoaderFactory.createCompositeSequenceableLoader(sampleStreams);
-    eventDispatcher.mediaPeriodCreated();
+    mediaSourceEventDispatcher.mediaPeriodCreated();
  }
  public void updateManifest(SsManifest manifest) {
@@ -99,7 +103,7 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
      sampleStream.release();
    }
    callback = null;
-    eventDispatcher.mediaPeriodReleased();
+    mediaSourceEventDispatcher.mediaPeriodReleased();
  }
  // MediaPeriod implementation.
@@ -197,7 +201,7 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
  @Override
  public long readDiscontinuity() {
    if (!notifiedReadingStarted) {
-      eventDispatcher.readingStarted();
+      mediaSourceEventDispatcher.readingStarted();
      notifiedReadingStarted = true;
    }
    return C.TIME_UNSET;
@@ -254,8 +258,9 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
        allocator,
        positionUs,
        drmSessionManager,
+        drmEventDispatcher,
        loadErrorHandlingPolicy,
-        eventDispatcher);
+        mediaSourceEventDispatcher);
  }
  private static TrackGroupArray buildTrackGroups(

--- a/library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaSource.java
+++ b/library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaSource.java
@@ -26,6 +26,7 @@ import com.google.android.exoplayer2.ExoPlayerLibraryInfo;
 import com.google.android.exoplayer2.MediaItem;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.drm.DrmSession;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.offline.FilteringManifestParser;
 import com.google.android.exoplayer2.offline.StreamKey;
@@ -632,7 +633,8 @@ public final class SsMediaSource extends BaseMediaSource
  @Override
  public MediaPeriod createPeriod(MediaPeriodId id, Allocator allocator, long startPositionUs) {
-    EventDispatcher eventDispatcher = createEventDispatcher(id);
+    MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher = createEventDispatcher(id);
+    DrmSessionEventListener.EventDispatcher drmEventDispatcher = createDrmEventDispatcher(id);
    SsMediaPeriod period =
        new SsMediaPeriod(
            manifest,
@@ -640,8 +642,9 @@ public final class SsMediaSource extends BaseMediaSource
            mediaTransferListener,
            compositeSequenceableLoaderFactory,
            drmSessionManager,
+            drmEventDispatcher,
            loadErrorHandlingPolicy,
-            eventDispatcher,
+            mediaSourceEventDispatcher,
            manifestLoaderErrorThrower,
            allocator);
    mediaPeriods.add(period);

--- a/library/smoothstreaming/src/test/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaPeriodTest.java
+++ b/library/smoothstreaming/src/test/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaPeriodTest.java
@@ -22,10 +22,11 @@ import static org.mockito.Mockito.mock;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.source.CompositeSequenceableLoaderFactory;
 import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.smoothstreaming.manifest.SsManifest;
 import com.google.android.exoplayer2.testutil.MediaPeriodAsserts;
 import com.google.android.exoplayer2.testutil.MediaPeriodAsserts.FilterableManifestMediaPeriodFactory;
@@ -61,21 +62,22 @@ public class SsMediaPeriodTest {
            createStreamElement(
                /* name= */ "text", C.TRACK_TYPE_TEXT, createTextFormat(/* language= */ "eng")));
    FilterableManifestMediaPeriodFactory<SsManifest> mediaPeriodFactory =
-        (manifest, periodIndex) ->
+        (manifest, periodIndex) -> {
-            new SsMediaPeriod(
+          MediaPeriodId mediaPeriodId = new MediaPeriodId(/* periodUid= */ new Object());
+          return new SsMediaPeriod(
              manifest,
              mock(SsChunkSource.Factory.class),
              mock(TransferListener.class),
              mock(CompositeSequenceableLoaderFactory.class),
              mock(DrmSessionManager.class),
+              new DrmSessionEventListener.EventDispatcher()
+                  .withParameters(/* windowIndex= */ 0, mediaPeriodId),
              mock(LoadErrorHandlingPolicy.class),
-                new EventDispatcher()
+              new MediaSourceEventListener.EventDispatcher()
-                    .withParameters(
+                  .withParameters(/* windowIndex= */ 0, mediaPeriodId, /* mediaTimeOffsetMs= */ 0),
-                        /* windowIndex= */ 0,
-                        /* mediaPeriodId= */ new MediaPeriodId(/* periodUid= */ new Object()),
-                        /* mediaTimeOffsetMs= */ 0),
              mock(LoaderErrorThrower.class),
              mock(Allocator.class));
+        };
    MediaPeriodAsserts.assertGetStreamKeysAndManifestFilterIntegration(
        mediaPeriodFactory, testManifest);

--- a/playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/gts/DashWidevineOfflineTest.java
+++ b/playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/gts/DashWidevineOfflineTest.java
@@ -27,6 +27,7 @@ import androidx.test.rule.ActivityTestRule;
 import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.drm.DrmInitData;
 import com.google.android.exoplayer2.drm.DrmSession.DrmSessionException;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.OfflineLicenseHelper;
 import com.google.android.exoplayer2.source.dash.DashUtil;
 import com.google.android.exoplayer2.source.dash.manifest.DashManifest;
@@ -34,7 +35,6 @@ import com.google.android.exoplayer2.testutil.ActionSchedule;
 import com.google.android.exoplayer2.testutil.HostActivity;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DefaultHttpDataSourceFactory;
-import com.google.android.exoplayer2.util.MediaSourceEventDispatcher;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.Util;
 import java.io.IOException;
@@ -77,7 +77,9 @@ public final class DashWidevineOfflineTest {
    if (Util.SDK_INT >= 18) {
      offlineLicenseHelper =
          OfflineLicenseHelper.newWidevineInstance(
-              widevineLicenseUrl, httpDataSourceFactory, new MediaSourceEventDispatcher());
+              widevineLicenseUrl,
+              httpDataSourceFactory,
+              new DrmSessionEventListener.EventDispatcher());
    }
  }

--- a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeAdaptiveMediaPeriod.java
+++ b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeAdaptiveMediaPeriod.java
@@ -16,10 +16,11 @@
 package com.google.android.exoplayer2.testutil;
 import androidx.annotation.Nullable;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.source.CompositeSequenceableLoader;
 import com.google.android.exoplayer2.source.MediaPeriod;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.SampleStream;
 import com.google.android.exoplayer2.source.SequenceableLoader;
 import com.google.android.exoplayer2.source.TrackGroupArray;
@@ -53,7 +54,7 @@ public class FakeAdaptiveMediaPeriod extends FakeMediaPeriod
  public FakeAdaptiveMediaPeriod(
      TrackGroupArray trackGroupArray,
-      EventDispatcher eventDispatcher,
+      MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
      Allocator allocator,
      FakeChunkSource.Factory chunkSourceFactory,
      long durationUs,
@@ -63,8 +64,9 @@ public class FakeAdaptiveMediaPeriod extends FakeMediaPeriod
        /* trackDataFactory= */ (unusedFormat, unusedMediaPeriodId) -> {
          throw new RuntimeException("unused track data");
        },
-        eventDispatcher,
+        mediaSourceEventDispatcher,
        DrmSessionManager.DUMMY,
+        new DrmSessionEventListener.EventDispatcher(),
        /* deferOnPrepared= */ false);
    this.allocator = allocator;
    this.chunkSourceFactory = chunkSourceFactory;
@@ -143,8 +145,9 @@ public class FakeAdaptiveMediaPeriod extends FakeMediaPeriod
  protected final SampleStream createSampleStream(
      long positionUs,
      TrackSelection trackSelection,
+      MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
      DrmSessionManager drmSessionManager,
-      EventDispatcher eventDispatcher) {
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher) {
    FakeChunkSource chunkSource =
        chunkSourceFactory.createChunkSource(trackSelection, durationUs, transferListener);
    return new ChunkSampleStream<>(
@@ -156,8 +159,9 @@ public class FakeAdaptiveMediaPeriod extends FakeMediaPeriod
        allocator,
        positionUs,
        /* drmSessionManager= */ DrmSessionManager.getDummyDrmSessionManager(),
+        drmEventDispatcher,
        new DefaultLoadErrorHandlingPolicy(/* minimumLoadableRetryCount= */ 3),
-        eventDispatcher);
+        mediaSourceEventDispatcher);
  }
  @Override

--- a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeAdaptiveMediaSource.java
+++ b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeAdaptiveMediaSource.java
@@ -18,9 +18,10 @@ package com.google.android.exoplayer2.testutil;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.Timeline.Period;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.source.MediaSource;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.upstream.TransferListener;
@@ -53,13 +54,14 @@ public class FakeAdaptiveMediaSource extends FakeMediaSource {
      MediaPeriodId id,
      TrackGroupArray trackGroupArray,
      Allocator allocator,
+      MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
      DrmSessionManager drmSessionManager,
-      EventDispatcher eventDispatcher,
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher,
      @Nullable TransferListener transferListener) {
    Period period = Util.castNonNull(getTimeline()).getPeriodByUid(id.periodUid, new Period());
    return new FakeAdaptiveMediaPeriod(
        trackGroupArray,
-        eventDispatcher,
+        mediaSourceEventDispatcher,
        allocator,
        chunkSourceFactory,
        period.durationUs,

--- a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeMediaPeriod.java
+++ b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeMediaPeriod.java
@@ -26,11 +26,12 @@ import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.SeekParameters;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.source.LoadEventInfo;
 import com.google.android.exoplayer2.source.MediaPeriod;
 import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.SampleStream;
 import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
@@ -57,9 +58,10 @@ public class FakeMediaPeriod implements MediaPeriod {
  private final TrackGroupArray trackGroupArray;
  private final List<SampleStream> sampleStreams;
-  private final DrmSessionManager drmSessionManager;
-  private final EventDispatcher eventDispatcher;
  private final TrackDataFactory trackDataFactory;
+  private final MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher;
+  private final DrmSessionManager drmSessionManager;
+  private final DrmSessionEventListener.EventDispatcher drmEventDispatcher;
  private final long fakePreparationLoadTaskId;
  @Nullable private Handler playerHandler;
@@ -77,16 +79,19 @@ public class FakeMediaPeriod implements MediaPeriod {
   * @param trackGroupArray The track group array.
   * @param singleSampleTimeUs The timestamp to use for the single sample in each track, in
   *     microseconds.
-   * @param eventDispatcher A dispatcher for media source events.
+   * @param mediaSourceEventDispatcher A dispatcher for {@link MediaSourceEventListener} events.
   */
  public FakeMediaPeriod(
-      TrackGroupArray trackGroupArray, long singleSampleTimeUs, EventDispatcher eventDispatcher) {
+      TrackGroupArray trackGroupArray,
+      long singleSampleTimeUs,
+      MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher) {
    this(
        trackGroupArray,
        TrackDataFactory.singleSampleWithTimeUs(singleSampleTimeUs),
-        eventDispatcher,
+        mediaSourceEventDispatcher,
        DrmSessionManager.DUMMY,
-        /* deferOnPrepared= */ false);
+        new DrmSessionEventListener.EventDispatcher(),
+        /* deferOnPrepared */ false);
  }
  /**
@@ -95,22 +100,26 @@ public class FakeMediaPeriod implements MediaPeriod {
   * @param trackGroupArray The track group array.
   * @param singleSampleTimeUs The timestamp to use for the single sample in each track, in
   *     microseconds.
-   * @param eventDispatcher A dispatcher for media source events.
+   * @param mediaSourceEventDispatcher A dispatcher for {@link MediaSourceEventListener} events.
   * @param drmSessionManager The {@link DrmSessionManager} used for DRM interactions.
+   * @param drmEventDispatcher A dispatcher for {@link DrmSessionEventListener} events.
   * @param deferOnPrepared Whether {@link Callback#onPrepared(MediaPeriod)} should be called only
-   *     after {@link #setPreparationComplete()} has been called. If {@code false}
+   *     after {@link #setPreparationComplete()} has been called. If {@code false} preparation
+   *     completes immediately.
   */
  public FakeMediaPeriod(
      TrackGroupArray trackGroupArray,
      long singleSampleTimeUs,
-      EventDispatcher eventDispatcher,
+      MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
      DrmSessionManager drmSessionManager,
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher,
      boolean deferOnPrepared) {
    this(
        trackGroupArray,
        TrackDataFactory.singleSampleWithTimeUs(singleSampleTimeUs),
-        eventDispatcher,
+        mediaSourceEventDispatcher,
        drmSessionManager,
+        drmEventDispatcher,
        deferOnPrepared);
  }
@@ -120,8 +129,9 @@ public class FakeMediaPeriod implements MediaPeriod {
   * @param trackGroupArray The track group array.
   * @param trackDataFactory A source for the underlying sample data for each track in {@code
   *     trackGroupArray}.
-   * @param eventDispatcher A dispatcher for media source events.
+   * @param mediaSourceEventDispatcher A dispatcher for media source events.
   * @param drmSessionManager The DrmSessionManager used for DRM interactions.
+   * @param drmEventDispatcher A dispatcher for {@link DrmSessionEventListener} events.
   * @param deferOnPrepared Whether {@link Callback#onPrepared(MediaPeriod)} should be called only
   *     after {@link #setPreparationComplete()} has been called. If {@code false} preparation
   *     completes immediately.
@@ -129,18 +139,20 @@ public class FakeMediaPeriod implements MediaPeriod {
  public FakeMediaPeriod(
      TrackGroupArray trackGroupArray,
      TrackDataFactory trackDataFactory,
-      EventDispatcher eventDispatcher,
+      MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
      DrmSessionManager drmSessionManager,
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher,
      boolean deferOnPrepared) {
    this.trackGroupArray = trackGroupArray;
+    this.mediaSourceEventDispatcher = mediaSourceEventDispatcher;
    this.drmSessionManager = drmSessionManager;
-    this.eventDispatcher = eventDispatcher;
+    this.drmEventDispatcher = drmEventDispatcher;
    this.deferOnPrepared = deferOnPrepared;
    this.trackDataFactory = trackDataFactory;
    discontinuityPositionUs = C.TIME_UNSET;
    sampleStreams = new ArrayList<>();
    fakePreparationLoadTaskId = LoadEventInfo.getNewId();
-    eventDispatcher.mediaPeriodCreated();
+    mediaSourceEventDispatcher.mediaPeriodCreated();
  }
  /**
@@ -177,12 +189,12 @@ public class FakeMediaPeriod implements MediaPeriod {
    for (int i = 0; i < sampleStreams.size(); i++) {
      releaseSampleStream(sampleStreams.get(i));
    }
-    eventDispatcher.mediaPeriodReleased();
+    mediaSourceEventDispatcher.mediaPeriodReleased();
  }
  @Override
  public synchronized void prepare(Callback callback, long positionUs) {
-    eventDispatcher.loadStarted(
+    mediaSourceEventDispatcher.loadStarted(
        new LoadEventInfo(fakePreparationLoadTaskId, FAKE_DATA_SPEC, SystemClock.elapsedRealtime()),
        C.DATA_TYPE_MEDIA,
        C.TRACK_TYPE_UNKNOWN,
@@ -232,7 +244,13 @@ public class FakeMediaPeriod implements MediaPeriod {
        int indexInTrackGroup = selection.getIndexInTrackGroup(selection.getSelectedIndex());
        assertThat(indexInTrackGroup).isAtLeast(0);
        assertThat(indexInTrackGroup).isLessThan(trackGroup.length);
-        streams[i] = createSampleStream(positionUs, selection, drmSessionManager, eventDispatcher);
+        streams[i] =
+            createSampleStream(
+                positionUs,
+                selection,
+                mediaSourceEventDispatcher,
+                drmSessionManager,
+                drmEventDispatcher);
        sampleStreams.add(streams[i]);
        streamResetFlags[i] = true;
      }
@@ -254,7 +272,7 @@ public class FakeMediaPeriod implements MediaPeriod {
  public long readDiscontinuity() {
    assertThat(prepared).isTrue();
    if (!notifiedReadingStarted) {
-      eventDispatcher.readingStarted();
+      mediaSourceEventDispatcher.readingStarted();
      notifiedReadingStarted = true;
    }
    long positionDiscontinuityUs = this.discontinuityPositionUs;
@@ -304,23 +322,28 @@ public class FakeMediaPeriod implements MediaPeriod {
   *
   * @param positionUs The position at which the tracks were selected, in microseconds.
   * @param selection A selection of tracks.
+   * @param mediaSourceEventDispatcher A dispatcher for {@link MediaSourceEventListener} events that
+   *     should be used by the sample stream.
   * @param drmSessionManager The DRM session manager.
-   * @param eventDispatcher A dispatcher for events that should be used by the sample stream.
+   * @param drmEventDispatcher A dispatcher for {@link DrmSessionEventListener} events that should
+   *     be used by the sample stream.
   * @return A {@link SampleStream} for this selection.
   */
  protected SampleStream createSampleStream(
      long positionUs,
      TrackSelection selection,
+      MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
      DrmSessionManager drmSessionManager,
-      EventDispatcher eventDispatcher) {
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher) {
    FakeSampleStream sampleStream =
        new FakeSampleStream(
+            mediaSourceEventDispatcher,
            drmSessionManager,
-            eventDispatcher,
+            drmEventDispatcher,
            selection.getSelectedFormat(),
            trackDataFactory.create(
                selection.getSelectedFormat(),
-                Assertions.checkNotNull(eventDispatcher.mediaPeriodId)));
+                Assertions.checkNotNull(mediaSourceEventDispatcher.mediaPeriodId)));
    sampleStream.seekTo(positionUs);
    return sampleStream;
  }
@@ -329,7 +352,8 @@ public class FakeMediaPeriod implements MediaPeriod {
   * Seeks inside the given sample stream.
   *
   * @param sampleStream A sample stream that was created by a call to {@link
-   *     #createSampleStream(long, TrackSelection, DrmSessionManager, EventDispatcher)}.
+   *     #createSampleStream(long, TrackSelection, MediaSourceEventListener.EventDispatcher,
+   *     DrmSessionManager, DrmSessionEventListener.EventDispatcher)}.
   * @param positionUs The position to seek to, in microseconds.
   */
  protected void seekSampleStream(SampleStream sampleStream, long positionUs) {
@@ -341,7 +365,8 @@ public class FakeMediaPeriod implements MediaPeriod {
   * Releases the given sample stream.
   *
   * @param sampleStream A sample stream that was created by a call to {@link
-   *     #createSampleStream(long, TrackSelection, DrmSessionManager, EventDispatcher)}.
+   *     #createSampleStream(long, TrackSelection, MediaSourceEventListener.EventDispatcher,
+   *     DrmSessionManager, DrmSessionEventListener.EventDispatcher)}.
   */
  protected void releaseSampleStream(SampleStream sampleStream) {
    ((FakeSampleStream) sampleStream).release();
@@ -350,7 +375,7 @@ public class FakeMediaPeriod implements MediaPeriod {
  private void finishPreparation() {
    prepared = true;
    Util.castNonNull(prepareCallback).onPrepared(this);
-    eventDispatcher.loadCompleted(
+    mediaSourceEventDispatcher.loadCompleted(
        new LoadEventInfo(
            fakePreparationLoadTaskId,
            FAKE_DATA_SPEC,
@@ -373,7 +398,8 @@ public class FakeMediaPeriod implements MediaPeriod {
    /**
     * Returns the list of {@link FakeSampleStreamItem}s that will be passed to {@link
-     * FakeSampleStream#FakeSampleStream(DrmSessionManager, EventDispatcher, Format, List)}.
+     * FakeSampleStream#FakeSampleStream(MediaSourceEventListener.EventDispatcher,
+     * DrmSessionManager, DrmSessionEventListener.EventDispatcher, Format, List)}.
     *
     * @param format The format of the track to provide data for.
     * @param mediaPeriodId The {@link MediaPeriodId} to provide data for.

--- a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeMediaSource.java
+++ b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeMediaSource.java
@@ -26,6 +26,7 @@ import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.MediaItem;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.Timeline.Period;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.source.BaseMediaSource;
 import com.google.android.exoplayer2.source.ForwardingTimeline;
@@ -33,7 +34,7 @@ import com.google.android.exoplayer2.source.LoadEventInfo;
 import com.google.android.exoplayer2.source.MediaLoadData;
 import com.google.android.exoplayer2.source.MediaPeriod;
 import com.google.android.exoplayer2.source.MediaSource;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.testutil.FakeMediaPeriod.TrackDataFactory;
@@ -215,11 +216,19 @@ public class FakeMediaSource extends BaseMediaSource {
    int periodIndex = castNonNull(timeline).getIndexOfPeriod(id.periodUid);
    Assertions.checkArgument(periodIndex != C.INDEX_UNSET);
    Period period = timeline.getPeriod(periodIndex, new Period());
-    EventDispatcher eventDispatcher =
+    MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher =
        createEventDispatcher(period.windowIndex, id, period.getPositionInWindowMs());
+    DrmSessionEventListener.EventDispatcher drmEventDispatcher =
+        createDrmEventDispatcher(period.windowIndex, id);
    FakeMediaPeriod mediaPeriod =
        createFakeMediaPeriod(
-            id, trackGroupArray, allocator, drmSessionManager, eventDispatcher, transferListener);
+            id,
+            trackGroupArray,
+            allocator,
+            mediaSourceEventDispatcher,
+            drmSessionManager,
+            drmEventDispatcher,
+            transferListener);
    activeMediaPeriods.add(mediaPeriod);
    createdMediaPeriods.add(id);
    return mediaPeriod;
@@ -308,7 +317,10 @@ public class FakeMediaSource extends BaseMediaSource {
   * @param id The identifier of the period.
   * @param trackGroupArray The {@link TrackGroupArray} supported by the media period.
   * @param allocator An {@link Allocator} from which to obtain media buffer allocations.
-   * @param eventDispatcher An {@link EventDispatcher} to dispatch media source events.
+   * @param mediaSourceEventDispatcher An {@link MediaSourceEventListener.EventDispatcher} to
+   *     dispatch media source events.
+   * @param drmEventDispatcher An {@link MediaSourceEventListener.EventDispatcher} to dispatch DRM
+   *     events.
   * @param transferListener The transfer listener which should be informed of any data transfers.
   *     May be null if no listener is available.
   * @return A new {@link FakeMediaPeriod}.
@@ -318,8 +330,9 @@ public class FakeMediaSource extends BaseMediaSource {
      MediaPeriodId id,
      TrackGroupArray trackGroupArray,
      Allocator allocator,
+      MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
      DrmSessionManager drmSessionManager,
-      EventDispatcher eventDispatcher,
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher,
      @Nullable TransferListener transferListener) {
    long positionInWindowUs =
        timeline.getPeriodByUid(id.periodUid, new Period()).getPositionInWindowUs();
@@ -329,8 +342,9 @@ public class FakeMediaSource extends BaseMediaSource {
        trackDataFactory != null
            ? trackDataFactory
            : TrackDataFactory.singleSampleWithTimeUs(defaultFirstSampleTimeUs),
-        eventDispatcher,
+        mediaSourceEventDispatcher,
        drmSessionManager,
+        drmEventDispatcher,
        /* deferOnPrepared= */ false);
  }
@@ -347,7 +361,8 @@ public class FakeMediaSource extends BaseMediaSource {
              /* mediaStartTimeMs= */ C.TIME_UNSET,
              /* mediaEndTimeMs = */ C.TIME_UNSET);
      long elapsedRealTimeMs = SystemClock.elapsedRealtime();
-      EventDispatcher eventDispatcher = createEventDispatcher(/* mediaPeriodId= */ null);
+      MediaSourceEventListener.EventDispatcher eventDispatcher =
+          createEventDispatcher(/* mediaPeriodId= */ null);
      long loadTaskId = LoadEventInfo.getNewId();
      eventDispatcher.loadStarted(
          new LoadEventInfo(

--- a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeSampleStream.java
+++ b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeSampleStream.java
@@ -25,8 +25,9 @@ import com.google.android.exoplayer2.FormatHolder;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
 import com.google.android.exoplayer2.drm.DrmInitData;
 import com.google.android.exoplayer2.drm.DrmSession;
+import com.google.android.exoplayer2.drm.DrmSessionEventListener;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
-import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.SampleStream;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.MimeTypes;
@@ -126,10 +127,11 @@ public class FakeSampleStream implements SampleStream {
    }
  }
+  @Nullable private final MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher;
  private final Format initialFormat;
  private final List<FakeSampleStreamItem> fakeSampleStreamItems;
  private final DrmSessionManager drmSessionManager;
-  @Nullable private final EventDispatcher eventDispatcher;
+  private final DrmSessionEventListener.EventDispatcher drmEventDispatcher;
  private int sampleItemIndex;
  private @MonotonicNonNull Format downstreamFormat;
@@ -140,8 +142,11 @@ public class FakeSampleStream implements SampleStream {
   * Creates a fake sample stream which outputs the given {@link Format} followed by the provided
   * {@link FakeSampleStreamItem items}.
   *
+   * @param mediaSourceEventDispatcher A {@link MediaSourceEventListener.EventDispatcher} to notify
+   *     of media events.
   * @param drmSessionManager A {@link DrmSessionManager} for DRM interactions.
-   * @param eventDispatcher An {@link EventDispatcher} to notify of read events.
+   * @param drmEventDispatcher A {@link DrmSessionEventListener.EventDispatcher} to notify of DRM
+   *     events.
   * @param initialFormat The first {@link Format} to output.
   * @param fakeSampleStreamItems The {@link FakeSampleStreamItem items} to customize the return
   *     values of {@link #readData(FormatHolder, DecoderInputBuffer, boolean)}. This is assumed to
@@ -150,12 +155,14 @@ public class FakeSampleStream implements SampleStream {
   *     FakeSampleStreamItem#END_OF_STREAM_ITEM}.
   */
  public FakeSampleStream(
+      @Nullable MediaSourceEventListener.EventDispatcher mediaSourceEventDispatcher,
      DrmSessionManager drmSessionManager,
-      @Nullable EventDispatcher eventDispatcher,
+      DrmSessionEventListener.EventDispatcher drmEventDispatcher,
      Format initialFormat,
      List<FakeSampleStreamItem> fakeSampleStreamItems) {
+    this.mediaSourceEventDispatcher = mediaSourceEventDispatcher;
    this.drmSessionManager = drmSessionManager;
-    this.eventDispatcher = eventDispatcher;
+    this.drmEventDispatcher = drmEventDispatcher;
    this.initialFormat = initialFormat;
    this.fakeSampleStreamItems = new ArrayList<>(fakeSampleStreamItems);
  }
@@ -268,13 +275,13 @@ public class FakeSampleStream implements SampleStream {
    Looper playbackLooper = Assertions.checkNotNull(Looper.myLooper());
    currentDrmSession =
        newDrmInitData != null
-            ? drmSessionManager.acquireSession(playbackLooper, eventDispatcher, newDrmInitData)
+            ? drmSessionManager.acquireSession(playbackLooper, drmEventDispatcher, newDrmInitData)
            : drmSessionManager.acquirePlaceholderSession(
                playbackLooper, MimeTypes.getTrackType(newFormat.sampleMimeType));
    outputFormatHolder.drmSession = currentDrmSession;
    if (previousSession != null) {
-      previousSession.release(eventDispatcher);
+      previousSession.release(drmEventDispatcher);
    }
  }
@@ -308,13 +315,13 @@ public class FakeSampleStream implements SampleStream {
  /** Release this SampleStream and all underlying resources. */
  public void release() {
    if (currentDrmSession != null) {
-      currentDrmSession.release(eventDispatcher);
+      currentDrmSession.release(drmEventDispatcher);
      currentDrmSession = null;
    }
  }
  private void notifyEventDispatcher(Format format) {
-    if (eventDispatcher != null) {
+    if (mediaSourceEventDispatcher != null) {
      @Nullable SampleInfo sampleInfo = null;
      for (int i = sampleItemIndex; i < fakeSampleStreamItems.size(); i++) {
        sampleInfo = fakeSampleStreamItems.get(i).sampleInfo;
@@ -323,7 +330,7 @@ public class FakeSampleStream implements SampleStream {
        }
      }
      long nextSampleTimeUs = sampleInfo != null ? sampleInfo.timeUs : C.TIME_END_OF_SOURCE;
-      eventDispatcher.downstreamFormatChanged(
+      mediaSourceEventDispatcher.downstreamFormatChanged(
          C.TRACK_TYPE_UNKNOWN,
          format,
          C.SELECTION_REASON_UNKNOWN,