Make usage of live minDurationForQualityIncrease more consistent

We have two ways to choose the minDurationForQualityIncreaseMs value in AdaptiveTrackSelection: use the configured value for non-live or when enough buffered data is available, or use a fraction of the available duration to allow switching when playing close to the live edge. The decision point when to use which value isn't quite consistent because we compare against availableDurationUs before making the adjustments. This means there is range of values where no up-switching is possible despite perfect buffering. Fix this by choosing the minimum of both values. Issue: google/ExoPlayer#9784 #minor-release PiperOrigin-RevId: 428474332
androidx · Feb 21, 2022 · 418726d · 418726d
1 parent 2b817fb
commit 418726d
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Showing 2 changed files with 15 additions and 8 deletions.
diff --git a/...player/src/main/java/androidx/media3/exoplayer/trackselection/AdaptiveTrackSelection.java b/...player/src/main/java/androidx/media3/exoplayer/trackselection/AdaptiveTrackSelection.java
@@ -16,6 +16,7 @@
 package androidx.media3.exoplayer.trackselection;
 
 import static java.lang.Math.max;
+import static java.lang.Math.min;
 
 import androidx.annotation.CallSuper;
 import androidx.annotation.Nullable;
@@ -605,10 +606,8 @@ private int determineIdealSelectedIndex(long nowMs, long chunkDurationUs) {
   }
 
   private long minDurationForQualityIncreaseUs(long availableDurationUs, long chunkDurationUs) {
-    boolean isAvailableDurationTooShort =
-        availableDurationUs != C.TIME_UNSET
-            && availableDurationUs <= minDurationForQualityIncreaseUs;
-    if (!isAvailableDurationTooShort) {
+    if (availableDurationUs == C.TIME_UNSET) {
+      // We are not in a live stream. Use the configured value.
       return minDurationForQualityIncreaseUs;
     }
     if (chunkDurationUs != C.TIME_UNSET) {
@@ -619,7 +618,9 @@ private long minDurationForQualityIncreaseUs(long availableDurationUs, long chun
       // actually achievable.
       availableDurationUs -= chunkDurationUs;
     }
-    return (long) (availableDurationUs * bufferedFractionToLiveEdgeForQualityIncrease);
+    long adjustedMinDurationForQualityIncreaseUs =
+        (long) (availableDurationUs * bufferedFractionToLiveEdgeForQualityIncrease);
+    return min(adjustedMinDurationForQualityIncreaseUs, minDurationForQualityIncreaseUs);
   }
 
   /**

diff --git a/...er/src/test/java/androidx/media3/exoplayer/trackselection/AdaptiveTrackSelectionTest.java b/...er/src/test/java/androidx/media3/exoplayer/trackselection/AdaptiveTrackSelectionTest.java
@@ -175,7 +175,9 @@ public void updateSelectedTrack_liveStream_switchesUpWhenBufferedFractionToLiveE
     when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(1000L, 2000L);
     AdaptiveTrackSelection adaptiveTrackSelection =
         prepareAdaptiveTrackSelectionWithBufferedFractionToLiveEdgeForQualiyIncrease(
-            trackGroup, /* bufferedFractionToLiveEdgeForQualityIncrease= */ 0.75f);
+            trackGroup,
+            /* bufferedFractionToLiveEdgeForQualityIncrease= */ 0.75f,
+            /* minDurationForQualityIncreaseMs= */ 5000);
 
     // Not buffered close to live edge yet.
     adaptiveTrackSelection.updateSelectedTrack(
@@ -188,6 +190,8 @@ public void updateSelectedTrack_liveStream_switchesUpWhenBufferedFractionToLiveE
     assertThat(adaptiveTrackSelection.getSelectedFormat()).isEqualTo(format2);
 
     // Buffered all possible chunks (except for newly added chunk of 2 seconds).
+    // Intentionally choose a situation where availableDurationUs > minDurationForQualityIncreaseMs
+    // to ensure the live calculation is used regardless.
     adaptiveTrackSelection.updateSelectedTrack(
         /* playbackPositionUs= */ 0,
         /* bufferedDurationUs= */ 3_600_000,
@@ -768,14 +772,16 @@ private AdaptiveTrackSelection prepareAdaptiveTrackSelectionWithMaxResolutionToD
 
   private AdaptiveTrackSelection
       prepareAdaptiveTrackSelectionWithBufferedFractionToLiveEdgeForQualiyIncrease(
-          TrackGroup trackGroup, float bufferedFractionToLiveEdgeForQualityIncrease) {
+          TrackGroup trackGroup,
+          float bufferedFractionToLiveEdgeForQualityIncrease,
+          long minDurationForQualityIncreaseMs) {
     return prepareTrackSelection(
         new AdaptiveTrackSelection(
             trackGroup,
             selectedAllTracksInGroup(trackGroup),
             TrackSelection.TYPE_UNSET,
             mockBandwidthMeter,
-            AdaptiveTrackSelection.DEFAULT_MIN_DURATION_FOR_QUALITY_INCREASE_MS,
+            minDurationForQualityIncreaseMs,
             AdaptiveTrackSelection.DEFAULT_MAX_DURATION_FOR_QUALITY_DECREASE_MS,
             AdaptiveTrackSelection.DEFAULT_MIN_DURATION_TO_RETAIN_AFTER_DISCARD_MS,
             AdaptiveTrackSelection.DEFAULT_MAX_WIDTH_TO_DISCARD,