Add Period.isPlaceholder to fix preparation issues for concatenation.

We added a source that allows mixed placeholder and non-placeholder
periods, but have no way to denote that in the Timeline because the
placeholder flag only exists on Window level. This causes a bug if
the first item in a concatenation has a window-period offset and the
player can't detect whether it's still a placeholder or not.

Adding this flag to Period allows the player to detect this reliably.
In addition we need to make sure that re-resolving pending positions
only happens for the first placeholder period where the window-offset
can actually change. As all subsequent periods have to start at position
0, so they don't need to be re-resolved (and shouldn't).

PiperOrigin-RevId: 367171518

library/common/src/main/java/com/google/android/exoplayer2/Timeline.java

@@ -589,6 +589,12 @@ public abstract class Timeline implements Bundleable {
      */
     public long positionInWindowUs;
 
+    /**
+     * Whether this period contains placeholder information because the real information has yet to
+     * be loaded.
+     */
+    public boolean isPlaceholder;
+
     private AdPlaybackState adPlaybackState;
 
     /** Creates a new instance with no ad playback state. */
@@ -650,6 +656,7 @@ public abstract class Timeline implements Bundleable {
       this.durationUs = durationUs;
       this.positionInWindowUs = positionInWindowUs;
       this.adPlaybackState = adPlaybackState;
+      this.isPlaceholder = false;
       return this;
     }
 
@@ -814,6 +821,7 @@ public abstract class Timeline implements Bundleable {
           && windowIndex == that.windowIndex
           && durationUs == that.durationUs
           && positionInWindowUs == that.positionInWindowUs
+          && isPlaceholder == that.isPlaceholder
           && Util.areEqual(adPlaybackState, that.adPlaybackState);
     }
 
@@ -825,6 +833,7 @@ public abstract class Timeline implements Bundleable {
       result = 31 * result + windowIndex;
       result = 31 * result + (int) (durationUs ^ (durationUs >>> 32));
       result = 31 * result + (int) (positionInWindowUs ^ (positionInWindowUs >>> 32));
+      result = 31 * result + (isPlaceholder ? 1 : 0);
       result = 31 * result + adPlaybackState.hashCode();
       return result;
     }
@@ -837,6 +846,7 @@ public abstract class Timeline implements Bundleable {
       FIELD_WINDOW_INDEX,
       FIELD_DURATION_US,
       FIELD_POSITION_IN_WINDOW_US,
+      FIELD_PLACEHOLDER,
       FIELD_AD_PLAYBACK_STATE
     })
     private @interface FieldNumber {}
@@ -844,7 +854,8 @@ public abstract class Timeline implements Bundleable {
     private static final int FIELD_WINDOW_INDEX = 0;
     private static final int FIELD_DURATION_US = 1;
     private static final int FIELD_POSITION_IN_WINDOW_US = 2;
-    private static final int FIELD_AD_PLAYBACK_STATE = 3;
+    private static final int FIELD_PLACEHOLDER = 3;
+    private static final int FIELD_AD_PLAYBACK_STATE = 4;
 
     /**
      * {@inheritDoc}
@@ -859,6 +870,7 @@ public abstract class Timeline implements Bundleable {
       bundle.putInt(keyForField(FIELD_WINDOW_INDEX), windowIndex);
       bundle.putLong(keyForField(FIELD_DURATION_US), durationUs);
       bundle.putLong(keyForField(FIELD_POSITION_IN_WINDOW_US), positionInWindowUs);
+      bundle.putBoolean(keyForField(FIELD_PLACEHOLDER), isPlaceholder);
       bundle.putBundle(keyForField(FIELD_AD_PLAYBACK_STATE), adPlaybackState.toBundle());
       return bundle;
     }
@@ -876,6 +888,7 @@ public abstract class Timeline implements Bundleable {
           bundle.getLong(keyForField(FIELD_DURATION_US), /* defaultValue= */ C.TIME_UNSET);
       long positionInWindowUs =
           bundle.getLong(keyForField(FIELD_POSITION_IN_WINDOW_US), /* defaultValue= */ 0);
+      boolean isPlaceholder = bundle.getBoolean(keyForField(FIELD_PLACEHOLDER));
       @Nullable
       Bundle adPlaybackStateBundle = bundle.getBundle(keyForField(FIELD_AD_PLAYBACK_STATE));
       AdPlaybackState adPlaybackState =
@@ -884,13 +897,15 @@ public abstract class Timeline implements Bundleable {
               : AdPlaybackState.NONE;
 
       Period period = new Period();
-      return period.set(
+      period.set(
           /* id= */ null,
           /* uid= */ null,
           windowIndex,
           durationUs,
           positionInWindowUs,
           adPlaybackState);
+      period.isPlaceholder = isPlaceholder;
+      return period;
     }
 
     private static String keyForField(@Period.FieldNumber int field) {
@@ -1469,8 +1484,9 @@ public abstract class Timeline implements Bundleable {
     @Override
     public Period getPeriod(int periodIndex, Period period, boolean ignoredSetIds) {
       Period p = periods.get(periodIndex);
-      return period.set(
-          p.id, p.uid, p.windowIndex, p.durationUs, p.positionInWindowUs, p.adPlaybackState);
+      period.set(p.id, p.uid, p.windowIndex, p.durationUs, p.positionInWindowUs, p.adPlaybackState);
+      period.isPlaceholder = p.isPlaceholder;
+      return period;
     }
 
     @Override

library/common/src/test/java/com/google/android/exoplayer2/TimelineTest.java

@@ -176,10 +176,15 @@ public class TimelineTest {
     assertThat(period).isNotEqualTo(otherPeriod);
 
     otherPeriod = new Timeline.Period();
+    otherPeriod.isPlaceholder = true;
+    assertThat(period).isNotEqualTo(otherPeriod);
+
+    otherPeriod = new Timeline.Period();
     period.id = new Object();
     period.uid = new Object();
     period.windowIndex = 1;
     period.durationUs = 123L;
+    period.isPlaceholder = true;
     otherPeriod =
         otherPeriod.set(
             period.id,
@@ -187,6 +192,7 @@ public class TimelineTest {
             period.windowIndex,
             period.durationUs,
             /* positionInWindowUs= */ 0);
+    otherPeriod.isPlaceholder = true;
     assertThat(period).isEqualTo(otherPeriod);
   }
 
@@ -323,6 +329,7 @@ public class TimelineTest {
     period.windowIndex = 1;
     period.durationUs = 123_000;
     period.positionInWindowUs = 4_000;
+    period.isPlaceholder = true;
 
     Timeline.Period restoredPeriod = Timeline.Period.CREATOR.fromBundle(period.toBundle());
 

library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImplInternal.java

@@ -1369,7 +1369,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
     MediaPeriodId mediaPeriodId = playbackInfo.periodId;
     long startPositionUs = playbackInfo.positionUs;
     long requestedContentPositionUs =
-        shouldUseRequestedContentPosition(playbackInfo, period, window)
+        shouldUseRequestedContentPosition(playbackInfo, period)
             ? playbackInfo.requestedContentPositionUs
             : playbackInfo.positionUs;
     boolean resetTrackInfo = false;
@@ -1821,9 +1821,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
             periodPositionChanged
                 && isSourceRefresh
                 && !oldTimeline.isEmpty()
-                && !oldTimeline.getWindow(
-                        oldTimeline.getPeriodByUid(oldPeriodUid, period).windowIndex, window)
-                    .isPlaceholder;
+                && !oldTimeline.getPeriodByUid(oldPeriodUid, period).isPlaceholder;
         playbackInfo =
             handlePositionDiscontinuity(
                 newPeriodId,
@@ -2478,7 +2476,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
     MediaPeriodId oldPeriodId = playbackInfo.periodId;
     Object newPeriodUid = oldPeriodId.periodUid;
     boolean shouldUseRequestedContentPosition =
-        shouldUseRequestedContentPosition(playbackInfo, period, window);
+        shouldUseRequestedContentPosition(playbackInfo, period);
     long oldContentPositionUs =
         shouldUseRequestedContentPosition
             ? playbackInfo.requestedContentPositionUs
@@ -2551,12 +2549,17 @@ import java.util.concurrent.atomic.AtomicBoolean;
             timeline.getPeriodByUid(newPeriodUid, period).windowIndex;
       } else {
         playbackInfo.timeline.getPeriodByUid(oldPeriodId.periodUid, period);
-        long windowPositionUs = oldContentPositionUs + period.getPositionInWindowUs();
-        int windowIndex = timeline.getPeriodByUid(newPeriodUid, period).windowIndex;
-        Pair<Object, Long> periodPosition =
-            timeline.getPeriodPosition(window, period, windowIndex, windowPositionUs);
-        newPeriodUid = periodPosition.first;
-        newContentPositionUs = periodPosition.second;
+        if (playbackInfo.timeline.getWindow(period.windowIndex, window).firstPeriodIndex
+            == playbackInfo.timeline.getIndexOfPeriod(oldPeriodId.periodUid)) {
+          // Only need to resolve the first period in a window because subsequent periods must start
+          // at position 0 and don't need to be resolved.
+          long windowPositionUs = oldContentPositionUs + period.getPositionInWindowUs();
+          int windowIndex = timeline.getPeriodByUid(newPeriodUid, period).windowIndex;
+          Pair<Object, Long> periodPosition =
+              timeline.getPeriodPosition(window, period, windowIndex, windowPositionUs);
+          newPeriodUid = periodPosition.first;
+          newContentPositionUs = periodPosition.second;
+        }
         // Use an explicitly requested content position as new target live offset.
         setTargetLiveOffset = true;
       }
@@ -2616,16 +2619,14 @@ import java.util.concurrent.atomic.AtomicBoolean;
   }
 
   private static boolean shouldUseRequestedContentPosition(
-      PlaybackInfo playbackInfo, Timeline.Period period, Timeline.Window window) {
+      PlaybackInfo playbackInfo, Timeline.Period period) {
     // Only use the actual position as content position if it's not an ad and we already have
     // prepared media information. Otherwise use the requested position.
     MediaPeriodId periodId = playbackInfo.periodId;
     Timeline timeline = playbackInfo.timeline;
     return periodId.isAd()
         || timeline.isEmpty()
-        || timeline.getWindow(
-                timeline.getPeriodByUid(periodId.periodUid, period).windowIndex, window)
-            .isPlaceholder;
+        || timeline.getPeriodByUid(periodId.periodUid, period).isPlaceholder;
   }
 
   /**
@@ -2691,9 +2692,12 @@ import java.util.concurrent.atomic.AtomicBoolean;
     }
     pendingMessageInfo.resolvedPeriodIndex = index;
     previousTimeline.getPeriodByUid(pendingMessageInfo.resolvedPeriodUid, period);
-    if (previousTimeline.getWindow(period.windowIndex, window).isPlaceholder) {
+    if (period.isPlaceholder
+        && previousTimeline.getWindow(period.windowIndex, window).firstPeriodIndex
+            == previousTimeline.getIndexOfPeriod(pendingMessageInfo.resolvedPeriodUid)) {
       // The position needs to be re-resolved because the window in the previous timeline wasn't
-      // fully prepared.
+      // fully prepared. Only resolve the first period in a window because subsequent periods must
+      // start at position 0 and don't need to be resolved.
       long windowPositionUs =
           pendingMessageInfo.resolvedPeriodTimeUs + period.getPositionInWindowUs();
       int windowIndex =
@@ -2768,10 +2772,12 @@ import java.util.concurrent.atomic.AtomicBoolean;
     int periodIndex = timeline.getIndexOfPeriod(periodPosition.first);
     if (periodIndex != C.INDEX_UNSET) {
       // We successfully located the period in the internal timeline.
-      seekTimeline.getPeriodByUid(periodPosition.first, period);
-      if (seekTimeline.getWindow(period.windowIndex, window).isPlaceholder) {
+      if (seekTimeline.getPeriodByUid(periodPosition.first, period).isPlaceholder
+          && seekTimeline.getWindow(period.windowIndex, window).firstPeriodIndex
+              == seekTimeline.getIndexOfPeriod(periodPosition.first)) {
         // The seek timeline was using a placeholder, so we need to re-resolve using the updated
-        // timeline in case the resolved position changed.
+        // timeline in case the resolved position changed. Only resolve the first period in a window
+        // because subsequent periods must start at position 0 and don't need to be resolved.
         int newWindowIndex = timeline.getPeriodByUid(periodPosition.first, period).windowIndex;
         periodPosition =
             timeline.getPeriodPosition(

library/core/src/main/java/com/google/android/exoplayer2/source/MaskingMediaSource.java

@@ -395,12 +395,14 @@ public final class MaskingMediaSource extends CompositeMediaSource<Void> {
 
     @Override
     public Period getPeriod(int periodIndex, Period period, boolean setIds) {
-      return period.set(
+      period.set(
           /* id= */ setIds ? 0 : null,
           /* uid= */ setIds ? MaskingTimeline.MASKING_EXTERNAL_PERIOD_UID : null,
           /* windowIndex= */ 0,
           /* durationUs = */ C.TIME_UNSET,
           /* positionInWindowUs= */ 0);
+      period.isPlaceholder = true;
+      return period;
     }
 
     @Override

library/core/src/main/java/com/google/android/exoplayer2/source/ProgressiveMediaSource.java

@@ -387,6 +387,13 @@ public final class ProgressiveMediaSource extends BaseMediaSource
               window.isPlaceholder = true;
               return window;
             }
+
+            @Override
+            public Period getPeriod(int periodIndex, Period period, boolean setIds) {
+              super.getPeriod(periodIndex, period, setIds);
+              period.isPlaceholder = true;
+              return period;
+            }
           };
     }
     refreshSourceInfo(timeline);

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeTimeline.java

@@ -410,13 +410,15 @@ public final class FakeTimeline extends Timeline {
     } else {
       positionInWindowUs = periodDurationUs * windowPeriodIndex;
     }
-    return period.set(
+    period.set(
         id,
         uid,
         windowIndex,
         periodDurationUs,
         positionInWindowUs,
         windowDefinition.adPlaybackState);
+    period.isPlaceholder = windowDefinition.isPlaceholder;
+    return period;
   }
 
   @Override