Update default min duration for playbacks with video to match max duration.

Experiments show this is beneficial for rebuffers with only minor impact
on battery usage.

Configurations which explicitly set a minimum buffer duration are unaffected.

Issue:#2083
PiperOrigin-RevId: 244823642

RELEASENOTES.md

@@ -120,6 +120,8 @@
     order when in shuffle mode.
   * Allow handling of custom commands via `registerCustomCommandReceiver`.
   * Add ability to include an extras `Bundle` when reporting a custom error.
+* LoadControl: Set minimum buffer for playbacks with video equal to maximum
+  buffer ([#2083](https://github.com/google/ExoPlayer/issues/2083)).
 
 ### 2.9.6 ###
 

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

@@ -29,12 +29,14 @@ public class DefaultLoadControl implements LoadControl {
 
   /**
    * The default minimum duration of media that the player will attempt to ensure is buffered at all
-   * times, in milliseconds.
+   * times, in milliseconds. This value is only applied to playbacks without video.
    */
   public static final int DEFAULT_MIN_BUFFER_MS = 15000;
 
   /**
    * The default maximum duration of media that the player will attempt to buffer, in milliseconds.
+   * For playbacks with video, this is also the default minimum duration of media that the player
+   * will attempt to ensure is buffered.
    */
   public static final int DEFAULT_MAX_BUFFER_MS = 50000;
 
@@ -69,7 +71,8 @@ public class DefaultLoadControl implements LoadControl {
   public static final class Builder {
 
     private DefaultAllocator allocator;
-    private int minBufferMs;
+    private int minBufferAudioMs;
+    private int minBufferVideoMs;
     private int maxBufferMs;
     private int bufferForPlaybackMs;
     private int bufferForPlaybackAfterRebufferMs;
@@ -81,7 +84,8 @@ public class DefaultLoadControl implements LoadControl {
 
     /** Constructs a new instance. */
     public Builder() {
-      minBufferMs = DEFAULT_MIN_BUFFER_MS;
+      minBufferAudioMs = DEFAULT_MIN_BUFFER_MS;
+      minBufferVideoMs = DEFAULT_MAX_BUFFER_MS;
       maxBufferMs = DEFAULT_MAX_BUFFER_MS;
       bufferForPlaybackMs = DEFAULT_BUFFER_FOR_PLAYBACK_MS;
       bufferForPlaybackAfterRebufferMs = DEFAULT_BUFFER_FOR_PLAYBACK_AFTER_REBUFFER_MS;
@@ -125,7 +129,18 @@ public class DefaultLoadControl implements LoadControl {
         int bufferForPlaybackMs,
         int bufferForPlaybackAfterRebufferMs) {
       Assertions.checkState(!createDefaultLoadControlCalled);
-      this.minBufferMs = minBufferMs;
+      assertGreaterOrEqual(bufferForPlaybackMs, 0, "bufferForPlaybackMs", "0");
+      assertGreaterOrEqual(
+          bufferForPlaybackAfterRebufferMs, 0, "bufferForPlaybackAfterRebufferMs", "0");
+      assertGreaterOrEqual(minBufferMs, bufferForPlaybackMs, "minBufferMs", "bufferForPlaybackMs");
+      assertGreaterOrEqual(
+          minBufferMs,
+          bufferForPlaybackAfterRebufferMs,
+          "minBufferMs",
+          "bufferForPlaybackAfterRebufferMs");
+      assertGreaterOrEqual(maxBufferMs, minBufferMs, "maxBufferMs", "minBufferMs");
+      this.minBufferAudioMs = minBufferMs;
+      this.minBufferVideoMs = minBufferMs;
       this.maxBufferMs = maxBufferMs;
       this.bufferForPlaybackMs = bufferForPlaybackMs;
       this.bufferForPlaybackAfterRebufferMs = bufferForPlaybackAfterRebufferMs;
@@ -173,6 +188,7 @@ public class DefaultLoadControl implements LoadControl {
      */
     public Builder setBackBuffer(int backBufferDurationMs, boolean retainBackBufferFromKeyframe) {
       Assertions.checkState(!createDefaultLoadControlCalled);
+      assertGreaterOrEqual(backBufferDurationMs, 0, "backBufferDurationMs", "0");
       this.backBufferDurationMs = backBufferDurationMs;
       this.retainBackBufferFromKeyframe = retainBackBufferFromKeyframe;
       return this;
@@ -187,7 +203,8 @@ public class DefaultLoadControl implements LoadControl {
       }
       return new DefaultLoadControl(
           allocator,
-          minBufferMs,
+          minBufferAudioMs,
+          minBufferVideoMs,
           maxBufferMs,
           bufferForPlaybackMs,
           bufferForPlaybackAfterRebufferMs,
@@ -200,7 +217,8 @@ public class DefaultLoadControl implements LoadControl {
 
   private final DefaultAllocator allocator;
 
-  private final long minBufferUs;
+  private final long minBufferAudioUs;
+  private final long minBufferVideoUs;
   private final long maxBufferUs;
   private final long bufferForPlaybackUs;
   private final long bufferForPlaybackAfterRebufferUs;
@@ -211,6 +229,7 @@ public class DefaultLoadControl implements LoadControl {
 
   private int targetBufferSize;
   private boolean isBuffering;
+  private boolean hasVideo;
 
   /** Constructs a new instance, using the {@code DEFAULT_*} constants defined in this class. */
   @SuppressWarnings("deprecation")
@@ -220,16 +239,18 @@ public class DefaultLoadControl implements LoadControl {
 
   /** @deprecated Use {@link Builder} instead. */
   @Deprecated
-  @SuppressWarnings("deprecation")
   public DefaultLoadControl(DefaultAllocator allocator) {
     this(
         allocator,
-        DEFAULT_MIN_BUFFER_MS,
+        /* minBufferAudioMs= */ DEFAULT_MIN_BUFFER_MS,
+        /* minBufferVideoMs= */ DEFAULT_MAX_BUFFER_MS,
         DEFAULT_MAX_BUFFER_MS,
         DEFAULT_BUFFER_FOR_PLAYBACK_MS,
         DEFAULT_BUFFER_FOR_PLAYBACK_AFTER_REBUFFER_MS,
         DEFAULT_TARGET_BUFFER_BYTES,
-        DEFAULT_PRIORITIZE_TIME_OVER_SIZE_THRESHOLDS);
+        DEFAULT_PRIORITIZE_TIME_OVER_SIZE_THRESHOLDS,
+        DEFAULT_BACK_BUFFER_DURATION_MS,
+        DEFAULT_RETAIN_BACK_BUFFER_FROM_KEYFRAME);
   }
 
   /** @deprecated Use {@link Builder} instead. */
@@ -244,7 +265,8 @@ public class DefaultLoadControl implements LoadControl {
       boolean prioritizeTimeOverSizeThresholds) {
     this(
         allocator,
-        minBufferMs,
+        /* minBufferAudioMs= */ minBufferMs,
+        /* minBufferVideoMs= */ minBufferMs,
         maxBufferMs,
         bufferForPlaybackMs,
         bufferForPlaybackAfterRebufferMs,
@@ -256,7 +278,8 @@ public class DefaultLoadControl implements LoadControl {
 
   protected DefaultLoadControl(
       DefaultAllocator allocator,
-      int minBufferMs,
+      int minBufferAudioMs,
+      int minBufferVideoMs,
       int maxBufferMs,
       int bufferForPlaybackMs,
       int bufferForPlaybackAfterRebufferMs,
@@ -267,17 +290,27 @@ public class DefaultLoadControl implements LoadControl {
     assertGreaterOrEqual(bufferForPlaybackMs, 0, "bufferForPlaybackMs", "0");
     assertGreaterOrEqual(
         bufferForPlaybackAfterRebufferMs, 0, "bufferForPlaybackAfterRebufferMs", "0");
-    assertGreaterOrEqual(minBufferMs, bufferForPlaybackMs, "minBufferMs", "bufferForPlaybackMs");
     assertGreaterOrEqual(
-        minBufferMs,
+        minBufferAudioMs, bufferForPlaybackMs, "minBufferAudioMs", "bufferForPlaybackMs");
+    assertGreaterOrEqual(
+        minBufferVideoMs, bufferForPlaybackMs, "minBufferVideoMs", "bufferForPlaybackMs");
+    assertGreaterOrEqual(
+        minBufferAudioMs,
         bufferForPlaybackAfterRebufferMs,
-        "minBufferMs",
+        "minBufferAudioMs",
         "bufferForPlaybackAfterRebufferMs");
-    assertGreaterOrEqual(maxBufferMs, minBufferMs, "maxBufferMs", "minBufferMs");
+    assertGreaterOrEqual(
+        minBufferVideoMs,
+        bufferForPlaybackAfterRebufferMs,
+        "minBufferVideoMs",
+        "bufferForPlaybackAfterRebufferMs");
+    assertGreaterOrEqual(maxBufferMs, minBufferAudioMs, "maxBufferMs", "minBufferAudioMs");
+    assertGreaterOrEqual(maxBufferMs, minBufferVideoMs, "maxBufferMs", "minBufferVideoMs");
     assertGreaterOrEqual(backBufferDurationMs, 0, "backBufferDurationMs", "0");
 
     this.allocator = allocator;
-    this.minBufferUs = C.msToUs(minBufferMs);
+    this.minBufferAudioUs = C.msToUs(minBufferAudioMs);
+    this.minBufferVideoUs = C.msToUs(minBufferVideoMs);
     this.maxBufferUs = C.msToUs(maxBufferMs);
     this.bufferForPlaybackUs = C.msToUs(bufferForPlaybackMs);
     this.bufferForPlaybackAfterRebufferUs = C.msToUs(bufferForPlaybackAfterRebufferMs);
@@ -295,6 +328,7 @@ public class DefaultLoadControl implements LoadControl {
   @Override
   public void onTracksSelected(Renderer[] renderers, TrackGroupArray trackGroups,
       TrackSelectionArray trackSelections) {
+    hasVideo = hasVideo(renderers, trackSelections);
     targetBufferSize =
         targetBufferBytesOverwrite == C.LENGTH_UNSET
             ? calculateTargetBufferSize(renderers, trackSelections)
@@ -330,7 +364,7 @@ public class DefaultLoadControl implements LoadControl {
   @Override
   public boolean shouldContinueLoading(long bufferedDurationUs, float playbackSpeed) {
     boolean targetBufferSizeReached = allocator.getTotalBytesAllocated() >= targetBufferSize;
-    long minBufferUs = this.minBufferUs;
+    long minBufferUs = hasVideo ? minBufferVideoUs : minBufferAudioUs;
     if (playbackSpeed > 1) {
       // The playback speed is faster than real time, so scale up the minimum required media
       // duration to keep enough media buffered for a playout duration of minBufferUs.
@@ -384,6 +418,15 @@ public class DefaultLoadControl implements LoadControl {
     }
   }
 
+  private static boolean hasVideo(Renderer[] renderers, TrackSelectionArray trackSelectionArray) {
+    for (int i = 0; i < renderers.length; i++) {
+      if (renderers[i].getTrackType() == C.TRACK_TYPE_VIDEO && trackSelectionArray.get(i) != null) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   private static void assertGreaterOrEqual(int value1, int value2, String name1, String name2) {
     Assertions.checkArgument(value1 >= value2, name1 + " cannot be less than " + name2);
   }