Rollback of https://github.com/google/ExoPlayer/commit/75eab31d79aae73196a60fb24474da2a36855c4a

*** Original commit ***

Rollback of https://github.com/google/ExoPlayer/commit/0943886cbd7ee6c4e33ed731ddff0b23e5699abd

*** Original commit ***

Use last queue format instead of previous decision to select new track

We currently use the save...

***

PiperOrigin-RevId: 320015109

library/core/src/main/java/com/google/android/exoplayer2/trackselection/AdaptiveTrackSelection.java

@@ -428,33 +428,35 @@ public class AdaptiveTrackSelection extends BaseTrackSelection {
       return;
     }
 
-    // Stash the current selection, then make a new one.
-    int currentSelectedIndex = selectedIndex;
-    selectedIndex = determineIdealSelectedIndex(nowMs);
-    if (selectedIndex == currentSelectedIndex) {
-      return;
+    int previousSelectedIndex = selectedIndex;
+    int previousReason = reason;
+    int formatIndexOfPreviousChunk =
+        queue.isEmpty() ? C.INDEX_UNSET : indexOf(Iterables.getLast(queue).trackFormat);
+    if (formatIndexOfPreviousChunk != C.INDEX_UNSET) {
+      previousSelectedIndex = formatIndexOfPreviousChunk;
+      previousReason = Iterables.getLast(queue).trackSelectionReason;
     }
-
-    if (!isBlacklisted(currentSelectedIndex, nowMs)) {
-      // Revert back to the current selection if conditions are not suitable for switching.
-      Format currentFormat = getFormat(currentSelectedIndex);
-      Format selectedFormat = getFormat(selectedIndex);
+    int newSelectedIndex = determineIdealSelectedIndex(nowMs);
+    if (!isBlacklisted(previousSelectedIndex, nowMs)) {
+      // Revert back to the previous selection if conditions are not suitable for switching.
+      Format currentFormat = getFormat(previousSelectedIndex);
+      Format selectedFormat = getFormat(newSelectedIndex);
       if (selectedFormat.bitrate > currentFormat.bitrate
           && bufferedDurationUs < minDurationForQualityIncreaseUs(availableDurationUs)) {
         // The selected track is a higher quality, but we have insufficient buffer to safely switch
         // up. Defer switching up for now.
-        selectedIndex = currentSelectedIndex;
+        newSelectedIndex = previousSelectedIndex;
       } else if (selectedFormat.bitrate < currentFormat.bitrate
           && bufferedDurationUs >= maxDurationForQualityDecreaseUs) {
         // The selected track is a lower quality, but we have sufficient buffer to defer switching
         // down for now.
-        selectedIndex = currentSelectedIndex;
+        newSelectedIndex = previousSelectedIndex;
       }
     }
     // If we adapted, update the trigger.
-    if (selectedIndex != currentSelectedIndex) {
-      reason = C.SELECTION_REASON_ADAPTIVE;
-    }
+    reason =
+        newSelectedIndex == previousSelectedIndex ? previousReason : C.SELECTION_REASON_ADAPTIVE;
+    selectedIndex = newSelectedIndex;
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/trackselection/BaseTrackSelection.java

@@ -24,7 +24,6 @@ import com.google.android.exoplayer2.source.chunk.MediaChunk;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Util;
 import java.util.Arrays;
-import java.util.Comparator;
 import java.util.List;
 
 /**
@@ -69,7 +68,8 @@ public abstract class BaseTrackSelection implements TrackSelection {
     for (int i = 0; i < tracks.length; i++) {
       formats[i] = group.getFormat(tracks[i]);
     }
-    Arrays.sort(formats, new DecreasingBandwidthComparator());
+    // Sort in order of decreasing bandwidth.
+    Arrays.sort(formats, (a, b) -> b.bitrate - a.bitrate);
     // Set the format indices in the same order.
     this.tracks = new int[length];
     for (int i = 0; i < length; i++) {
@@ -199,17 +199,4 @@ public abstract class BaseTrackSelection implements TrackSelection {
     BaseTrackSelection other = (BaseTrackSelection) obj;
     return group == other.group && Arrays.equals(tracks, other.tracks);
   }
-
-  /**
-   * Sorts {@link Format} objects in order of decreasing bandwidth.
-   */
-  private static final class DecreasingBandwidthComparator implements Comparator<Format> {
-
-    @Override
-    public int compare(Format a, Format b) {
-      return b.bitrate - a.bitrate;
-    }
-
-  }
-
 }

library/core/src/test/java/com/google/android/exoplayer2/trackselection/AdaptiveTrackSelectionTest.java

@@ -33,6 +33,7 @@ import com.google.android.exoplayer2.testutil.FakeMediaChunk;
 import com.google.android.exoplayer2.trackselection.TrackSelection.Definition;
 import com.google.android.exoplayer2.upstream.BandwidthMeter;
 import com.google.android.exoplayer2.util.MimeTypes;
+import com.google.common.collect.ImmutableList;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -328,6 +329,88 @@ public final class AdaptiveTrackSelectionTest {
     assertThat(newSize).isEqualTo(2);
   }
 
+  @Test
+  public void updateSelectedTrack_usesFormatOfLastChunkInTheQueueForSelection() {
+    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
+    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
+    TrackGroup trackGroup = new TrackGroup(format1, format2);
+    adaptiveTrackSelection =
+        new AdaptiveTrackSelection.Factory(
+                /* minDurationForQualityIncreaseMs= */ 10_000,
+                /* maxDurationForQualityDecreaseMs= */ 10_000,
+                /* minDurationToRetainAfterDiscardMs= */ 25_000,
+                /* bandwidthFraction= */ 1f)
+            .createAdaptiveTrackSelection(
+                trackGroup,
+                mockBandwidthMeter,
+                /* tracks= */ new int[] {0, 1},
+                /* totalFixedTrackBandwidth= */ 0);
+
+    // Make initial selection.
+    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(1000L);
+    prepareTrackSelection(adaptiveTrackSelection);
+
+    assertThat(adaptiveTrackSelection.getSelectedFormat()).isEqualTo(format2);
+    assertThat(adaptiveTrackSelection.getSelectionReason()).isEqualTo(C.SELECTION_REASON_INITIAL);
+
+    // Ensure that track selection wants to switch down due to low bandwidth.
+    FakeMediaChunk chunk1 =
+        new FakeMediaChunk(
+            format2, /* startTimeUs= */ 0, /* endTimeUs= */ 2_000_000, C.SELECTION_REASON_INITIAL);
+    FakeMediaChunk chunk2 =
+        new FakeMediaChunk(
+            format2,
+            /* startTimeUs= */ 2_000_000,
+            /* endTimeUs= */ 4_000_000,
+            C.SELECTION_REASON_INITIAL);
+    List<FakeMediaChunk> queue = ImmutableList.of(chunk1, chunk2);
+    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(500L);
+    adaptiveTrackSelection.updateSelectedTrack(
+        /* playbackPositionUs= */ 0,
+        /* bufferedDurationUs= */ 4_000_000,
+        /* availableDurationUs= */ C.TIME_UNSET,
+        queue,
+        /* mediaChunkIterators= */ THREE_EMPTY_MEDIA_CHUNK_ITERATORS);
+
+    assertThat(adaptiveTrackSelection.getSelectedFormat()).isEqualTo(format1);
+    assertThat(adaptiveTrackSelection.getSelectionReason()).isEqualTo(C.SELECTION_REASON_ADAPTIVE);
+
+    // Assert that an improved bandwidth selects the last chunk's format and ignores the previous
+    // decision. Switching up from the previous decision wouldn't be possible yet because the
+    // buffered duration is less than minDurationForQualityIncreaseMs.
+    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(1000L);
+    adaptiveTrackSelection.updateSelectedTrack(
+        /* playbackPositionUs= */ 0,
+        /* bufferedDurationUs= */ 4_000_000,
+        /* availableDurationUs= */ C.TIME_UNSET,
+        queue,
+        /* mediaChunkIterators= */ THREE_EMPTY_MEDIA_CHUNK_ITERATORS);
+
+    assertThat(adaptiveTrackSelection.getSelectedFormat()).isEqualTo(format2);
+    assertThat(adaptiveTrackSelection.getSelectionReason()).isEqualTo(C.SELECTION_REASON_INITIAL);
+  }
+
+  @Test
+  public void updateSelectedTrack_withQueueOfUnknownFormats_doesntThrow() {
+    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
+    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
+    TrackGroup trackGroup = new TrackGroup(format1, format2);
+    adaptiveTrackSelection = prepareTrackSelection(adaptiveTrackSelection(trackGroup));
+    Format unknownFormat = videoFormat(/* bitrate= */ 42, /* width= */ 300, /* height= */ 123);
+    FakeMediaChunk chunk =
+        new FakeMediaChunk(unknownFormat, /* startTimeUs= */ 0, /* endTimeUs= */ 2_000_000);
+    List<FakeMediaChunk> queue = ImmutableList.of(chunk);
+
+    adaptiveTrackSelection.updateSelectedTrack(
+        /* playbackPositionUs= */ 0,
+        /* bufferedDurationUs= */ 2_000_000,
+        /* availableDurationUs= */ C.TIME_UNSET,
+        queue,
+        /* mediaChunkIterators= */ THREE_EMPTY_MEDIA_CHUNK_ITERATORS);
+
+    assertThat(adaptiveTrackSelection.getSelectedFormat()).isAnyOf(format1, format2);
+  }
+
   private AdaptiveTrackSelection adaptiveTrackSelection(TrackGroup trackGroup) {
     return adaptiveTrackSelectionWithMinDurationForQualityIncreaseMs(
         trackGroup, AdaptiveTrackSelection.DEFAULT_MIN_DURATION_FOR_QUALITY_INCREASE_MS);

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

@@ -28,16 +28,31 @@ public final class FakeMediaChunk extends MediaChunk {
 
   private static final DataSource DATA_SOURCE = new DefaultHttpDataSource("TEST_AGENT");
 
+  /**
+   * Creates a fake media chunk.
+   *
+   * @param trackFormat The {@link Format}.
+   * @param startTimeUs The start time of the media, in microseconds.
+   * @param endTimeUs The end time of the media, in microseconds.
+   */
   public FakeMediaChunk(Format trackFormat, long startTimeUs, long endTimeUs) {
-    this(new DataSpec(Uri.EMPTY), trackFormat, startTimeUs, endTimeUs);
+    this(trackFormat, startTimeUs, endTimeUs, C.SELECTION_REASON_UNKNOWN);
   }
 
-  public FakeMediaChunk(DataSpec dataSpec, Format trackFormat, long startTimeUs, long endTimeUs) {
+  /**
+   * Creates a fake media chunk.
+   *
+   * @param trackFormat The {@link Format}.
+   * @param startTimeUs The start time of the media, in microseconds.
+   * @param endTimeUs The end time of the media, in microseconds.
+   * @param selectionReason The reason for selecting this format.
+   */
+  public FakeMediaChunk(Format trackFormat, long startTimeUs, long endTimeUs, int selectionReason) {
     super(
         DATA_SOURCE,
-        dataSpec,
+        new DataSpec(Uri.EMPTY),
         trackFormat,
-        C.SELECTION_REASON_ADAPTIVE,
+        selectionReason,
         /* trackSelectionData= */ null,
         startTimeUs,
         endTimeUs,