Testing Adaptive Track Selection Workflow in SmartTube

yuliskov/smarttube

exoplayer-amzn-2.10.6/library/core/src/test/java/com/google/android/exoplayer2/trackselection/AdaptiveTrackSelectionTest.java

            
/*
 * Copyright (C) 2017 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.trackselection;

import static com.google.common.truth.Truth.assertThat;
import static org.mockito.ArgumentMatchers.argThat;
import static org.mockito.Matchers.any;
import static org.mockito.Matchers.eq;
import static org.mockito.Mockito.atLeastOnce;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.verifyZeroInteractions;
import static org.mockito.Mockito.when;
import static org.mockito.MockitoAnnotations.initMocks;

import androidx.test.ext.junit.runners.AndroidJUnit4;
import com.google.android.exoplayer2.C;
import com.google.android.exoplayer2.Format;
import com.google.android.exoplayer2.source.TrackGroup;
import com.google.android.exoplayer2.source.chunk.MediaChunkIterator;
import com.google.android.exoplayer2.testutil.FakeClock;
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 java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.ArgumentMatcher;
import org.mockito.Mock;

/** Unit test for {@link AdaptiveTrackSelection}. */
@RunWith(AndroidJUnit4.class)
public final class AdaptiveTrackSelectionTest {

  private static final MediaChunkIterator[] THREE_EMPTY_MEDIA_CHUNK_ITERATORS =
      new MediaChunkIterator[] {
        MediaChunkIterator.EMPTY, MediaChunkIterator.EMPTY, MediaChunkIterator.EMPTY
      };

  @Mock private BandwidthMeter mockBandwidthMeter;
  private FakeClock fakeClock;

  private AdaptiveTrackSelection adaptiveTrackSelection;

  @Before
  public void setUp() {
    initMocks(this);
    fakeClock = new FakeClock(0);
  }

  @Test
  @SuppressWarnings("deprecation")
  public void testFactoryUsesInitiallyProvidedBandwidthMeter() {
    BandwidthMeter initialBandwidthMeter = mock(BandwidthMeter.class);
    BandwidthMeter injectedBandwidthMeter = mock(BandwidthMeter.class);
    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
    TrackSelection[] trackSelections =
        new AdaptiveTrackSelection.Factory(initialBandwidthMeter)
            .createTrackSelections(
                new Definition[] {
                  new Definition(new TrackGroup(format1, format2), /* tracks= */ 0, 1)
                },
                injectedBandwidthMeter);
    trackSelections[0].updateSelectedTrack(
        /* playbackPositionUs= */ 0,
        /* bufferedDurationUs= */ 0,
        /* availableDurationUs= */ C.TIME_UNSET,
        /* queue= */ Collections.emptyList(),
        /* mediaChunkIterators= */ new MediaChunkIterator[] {MediaChunkIterator.EMPTY});

    verify(initialBandwidthMeter, atLeastOnce()).getBitrateEstimate();
    verifyZeroInteractions(injectedBandwidthMeter);
  }

  @Test
  public void testSelectInitialIndexUseMaxInitialBitrateIfNoBandwidthEstimate() {
    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
    Format format3 = videoFormat(/* bitrate= */ 2000, /* width= */ 960, /* height= */ 720);
    TrackGroup trackGroup = new TrackGroup(format1, format2, format3);

    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(1000L);
    adaptiveTrackSelection = adaptiveTrackSelection(trackGroup);

    assertThat(adaptiveTrackSelection.getSelectedFormat()).isEqualTo(format2);
    assertThat(adaptiveTrackSelection.getSelectionReason()).isEqualTo(C.SELECTION_REASON_INITIAL);
  }

  @Test
  public void testSelectInitialIndexUseBandwidthEstimateIfAvailable() {
    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
    Format format3 = videoFormat(/* bitrate= */ 2000, /* width= */ 960, /* height= */ 720);
    TrackGroup trackGroup = new TrackGroup(format1, format2, format3);

    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(500L);
    adaptiveTrackSelection = adaptiveTrackSelection(trackGroup);

    assertThat(adaptiveTrackSelection.getSelectedFormat()).isEqualTo(format1);
    assertThat(adaptiveTrackSelection.getSelectionReason()).isEqualTo(C.SELECTION_REASON_INITIAL);
  }

  @Test
  public void testUpdateSelectedTrackDoNotSwitchUpIfNotBufferedEnough() {
    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
    Format format3 = videoFormat(/* bitrate= */ 2000, /* width= */ 960, /* height= */ 720);
    TrackGroup trackGroup = new TrackGroup(format1, format2, format3);

    // The second measurement onward returns 2000L, which prompts the track selection to switch up
    // if possible.
    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(1000L, 2000L);
    adaptiveTrackSelection =
        adaptiveTrackSelectionWithMinDurationForQualityIncreaseMs(
            trackGroup, /* minDurationForQualityIncreaseMs= */ 10_000);

    adaptiveTrackSelection.updateSelectedTrack(
        /* playbackPositionUs= */ 0,
        /* bufferedDurationUs= */ 9_999_000,
        /* availableDurationUs= */ C.TIME_UNSET,
        /* queue= */ Collections.emptyList(),
        /* mediaChunkIterators= */ THREE_EMPTY_MEDIA_CHUNK_ITERATORS);

    // When bandwidth estimation is updated to 2000L, we can switch up to use a higher bitrate
    // format. However, since we only buffered 9_999_000 us, which is smaller than
    // minDurationForQualityIncreaseMs, we should defer switch up.
    assertThat(adaptiveTrackSelection.getSelectedFormat()).isEqualTo(format2);
    assertThat(adaptiveTrackSelection.getSelectionReason()).isEqualTo(C.SELECTION_REASON_INITIAL);
  }

  @Test
  public void testUpdateSelectedTrackSwitchUpIfBufferedEnough() {
    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
    Format format3 = videoFormat(/* bitrate= */ 2000, /* width= */ 960, /* height= */ 720);
    TrackGroup trackGroup = new TrackGroup(format1, format2, format3);

    // The second measurement onward returns 2000L, which prompts the track selection to switch up
    // if possible.
    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(1000L, 2000L);
    adaptiveTrackSelection =
        adaptiveTrackSelectionWithMinDurationForQualityIncreaseMs(
            trackGroup, /* minDurationForQualityIncreaseMs= */ 10_000);

    adaptiveTrackSelection.updateSelectedTrack(
        /* playbackPositionUs= */ 0,
        /* bufferedDurationUs= */ 10_000_000,
        /* availableDurationUs= */ C.TIME_UNSET,
        /* queue= */ Collections.emptyList(),
        /* mediaChunkIterators= */ THREE_EMPTY_MEDIA_CHUNK_ITERATORS);

    // When bandwidth estimation is updated to 2000L, we can switch up to use a higher bitrate
    // format. When we have buffered enough (10_000_000 us, which is equal to
    // minDurationForQualityIncreaseMs), we should switch up now.
    assertThat(adaptiveTrackSelection.getSelectedFormat()).isEqualTo(format3);
    assertThat(adaptiveTrackSelection.getSelectionReason()).isEqualTo(C.SELECTION_REASON_ADAPTIVE);
  }

  @Test
  public void testUpdateSelectedTrackDoNotSwitchDownIfBufferedEnough() {
    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
    Format format3 = videoFormat(/* bitrate= */ 2000, /* width= */ 960, /* height= */ 720);
    TrackGroup trackGroup = new TrackGroup(format1, format2, format3);

    // The second measurement onward returns 500L, which prompts the track selection to switch down
    // if necessary.
    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(1000L, 500L);
    adaptiveTrackSelection =
        adaptiveTrackSelectionWithMaxDurationForQualityDecreaseMs(
            trackGroup, /* maxDurationForQualityDecreaseMs= */ 25_000);

    adaptiveTrackSelection.updateSelectedTrack(
        /* playbackPositionUs= */ 0,
        /* bufferedDurationUs= */ 25_000_000,
        /* availableDurationUs= */ C.TIME_UNSET,
        /* queue= */ Collections.emptyList(),
        /* mediaChunkIterators= */ THREE_EMPTY_MEDIA_CHUNK_ITERATORS);

    // When bandwidth estimation is updated to 500L, we should switch down to use a lower bitrate
    // format. However, since we have enough buffer at higher quality (25_000_000 us, which is equal
    // to maxDurationForQualityDecreaseMs), we should defer switch down.
    assertThat(adaptiveTrackSelection.getSelectedFormat()).isEqualTo(format2);
    assertThat(adaptiveTrackSelection.getSelectionReason()).isEqualTo(C.SELECTION_REASON_INITIAL);
  }

  @Test
  public void testUpdateSelectedTrackSwitchDownIfNotBufferedEnough() {
    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
    Format format3 = videoFormat(/* bitrate= */ 2000, /* width= */ 960, /* height= */ 720);
    TrackGroup trackGroup = new TrackGroup(format1, format2, format3);

    // The second measurement onward returns 500L, which prompts the track selection to switch down
    // if necessary.
    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(1000L, 500L);
    adaptiveTrackSelection =
        adaptiveTrackSelectionWithMaxDurationForQualityDecreaseMs(
            trackGroup, /* maxDurationForQualityDecreaseMs= */ 25_000);

    adaptiveTrackSelection.updateSelectedTrack(
        /* playbackPositionUs= */ 0,
        /* bufferedDurationUs= */ 24_999_000,
        /* availableDurationUs= */ C.TIME_UNSET,
        /* queue= */ Collections.emptyList(),
        /* mediaChunkIterators= */ THREE_EMPTY_MEDIA_CHUNK_ITERATORS);

    // When bandwidth estimation is updated to 500L, we should switch down to use a lower bitrate
    // format. When we don't have enough buffer at higher quality (24_999_000 us is smaller than
    // maxDurationForQualityDecreaseMs), we should switch down now.
    assertThat(adaptiveTrackSelection.getSelectedFormat()).isEqualTo(format1);
    assertThat(adaptiveTrackSelection.getSelectionReason()).isEqualTo(C.SELECTION_REASON_ADAPTIVE);
  }

  @Test
  public void testUpdateSelectedTrackSwitchUpIfTrackBitrateEstimateIsLow() {
    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
    Format format3 = videoFormat(/* bitrate= */ 2000, /* width= */ 960, /* height= */ 720);
    TrackGroup trackGroup = new TrackGroup(format1, format2, format3);

    // The second measurement onward returns 1500L, which isn't enough to switch up to format3 as
    // the format bitrate is 2000.
    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(1000L, 1500L);

    // But TrackBitrateEstimator returns 1500 for 3rd track so it should switch up.
    TrackBitrateEstimator estimator = mock(TrackBitrateEstimator.class);
    when(estimator.getBitrates(any(), any(), any(), any()))
        .then(
            (invocation) -> {
              int[] returnValue = new int[] {500, 1000, 1500};
              int[] inputArray = (int[]) invocation.getArguments()[3];
              System.arraycopy(returnValue, 0, inputArray, 0, returnValue.length);
              return returnValue;
            });

    adaptiveTrackSelection = adaptiveTrackSelection(trackGroup);
    adaptiveTrackSelection.experimental_setTrackBitrateEstimator(estimator);

    adaptiveTrackSelection.updateSelectedTrack(
        /* playbackPositionUs= */ 0,
        /* bufferedDurationUs= */ AdaptiveTrackSelection
                .DEFAULT_MIN_DURATION_FOR_QUALITY_INCREASE_MS
            * 1000,
        /* availableDurationUs= */ C.TIME_UNSET,
        /* queue= */ Collections.emptyList(),
        /* mediaChunkIterators= */ THREE_EMPTY_MEDIA_CHUNK_ITERATORS);

    ArgumentMatcher<Format[]> matcher =
        new ArgumentMatcher<Format[]>() {
          @Override
          public boolean matches(Format[] argument) {
            Format[] formats = (Format[]) argument;
            return formats.length == 3
                && Arrays.asList(formats).containsAll(Arrays.asList(format1, format2, format3));
          }
        };
    verify(estimator)
        .getBitrates(
            argThat(matcher),
            eq(Collections.emptyList()),
            eq(THREE_EMPTY_MEDIA_CHUNK_ITERATORS),
            any());
    assertThat(adaptiveTrackSelection.getSelectedFormat()).isEqualTo(format3);
    assertThat(adaptiveTrackSelection.getSelectionReason()).isEqualTo(C.SELECTION_REASON_ADAPTIVE);
  }

  @Test
  public void testEvaluateQueueSizeReturnQueueSizeIfBandwidthIsNotImproved() {
    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
    Format format3 = videoFormat(/* bitrate= */ 2000, /* width= */ 960, /* height= */ 720);
    TrackGroup trackGroup = new TrackGroup(format1, format2, format3);

    FakeMediaChunk chunk1 =
        new FakeMediaChunk(format1, /* startTimeUs= */ 0, /* endTimeUs= */ 10_000_000);
    FakeMediaChunk chunk2 =
        new FakeMediaChunk(format1, /* startTimeUs= */ 10_000_000, /* endTimeUs= */ 20_000_000);
    FakeMediaChunk chunk3 =
        new FakeMediaChunk(format1, /* startTimeUs= */ 20_000_000, /* endTimeUs= */ 30_000_000);
    List<FakeMediaChunk> queue = new ArrayList<>();
    queue.add(chunk1);
    queue.add(chunk2);
    queue.add(chunk3);

    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(500L);
    adaptiveTrackSelection = adaptiveTrackSelection(trackGroup);

    int size = adaptiveTrackSelection.evaluateQueueSize(0, queue);
    assertThat(size).isEqualTo(3);
  }

  @Test
  public void testEvaluateQueueSizeDoNotReevaluateUntilAfterMinTimeBetweenBufferReevaluation() {
    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
    Format format3 = videoFormat(/* bitrate= */ 2000, /* width= */ 960, /* height= */ 720);
    TrackGroup trackGroup = new TrackGroup(format1, format2, format3);

    FakeMediaChunk chunk1 =
        new FakeMediaChunk(format1, /* startTimeUs= */ 0, /* endTimeUs= */ 10_000_000);
    FakeMediaChunk chunk2 =
        new FakeMediaChunk(format1, /* startTimeUs= */ 10_000_000, /* endTimeUs= */ 20_000_000);
    FakeMediaChunk chunk3 =
        new FakeMediaChunk(format1, /* startTimeUs= */ 20_000_000, /* endTimeUs= */ 30_000_000);
    List<FakeMediaChunk> queue = new ArrayList<>();
    queue.add(chunk1);
    queue.add(chunk2);
    queue.add(chunk3);

    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(500L);
    adaptiveTrackSelection =
        adaptiveTrackSelectionWithMinTimeBetweenBufferReevaluationMs(
            trackGroup,
            /* durationToRetainAfterDiscardMs= */ 15_000,
            /* minTimeBetweenBufferReevaluationMs= */ 2000);

    int initialQueueSize = adaptiveTrackSelection.evaluateQueueSize(0, queue);

    fakeClock.advanceTime(1999);
    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(1000L);

    // When bandwidth estimation is updated, we can discard chunks at the end of the queue now.
    // However, since min duration between buffer reevaluation = 2000, we will not reevaluate
    // queue size if time now is only 1999 ms after last buffer reevaluation.
    int newSize = adaptiveTrackSelection.evaluateQueueSize(0, queue);
    assertThat(newSize).isEqualTo(initialQueueSize);
  }

  @Test
  public void testEvaluateQueueSizeRetainMoreThanMinimumDurationAfterDiscard() {
    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
    Format format3 = videoFormat(/* bitrate= */ 2000, /* width= */ 960, /* height= */ 720);
    TrackGroup trackGroup = new TrackGroup(format1, format2, format3);

    FakeMediaChunk chunk1 =
        new FakeMediaChunk(format1, /* startTimeUs= */ 0, /* endTimeUs= */ 10_000_000);
    FakeMediaChunk chunk2 =
        new FakeMediaChunk(format1, /* startTimeUs= */ 10_000_000, /* endTimeUs= */ 20_000_000);
    FakeMediaChunk chunk3 =
        new FakeMediaChunk(format1, /* startTimeUs= */ 20_000_000, /* endTimeUs= */ 30_000_000);
    List<FakeMediaChunk> queue = new ArrayList<>();
    queue.add(chunk1);
    queue.add(chunk2);
    queue.add(chunk3);

    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(500L);
    adaptiveTrackSelection =
        adaptiveTrackSelectionWithMinTimeBetweenBufferReevaluationMs(
            trackGroup,
            /* durationToRetainAfterDiscardMs= */ 15_000,
            /* minTimeBetweenBufferReevaluationMs= */ 2000);

    int initialQueueSize = adaptiveTrackSelection.evaluateQueueSize(0, queue);
    assertThat(initialQueueSize).isEqualTo(3);

    fakeClock.advanceTime(2000);
    when(mockBandwidthMeter.getBitrateEstimate()).thenReturn(1000L);

    // When bandwidth estimation is updated and time has advanced enough, we can discard chunks at
    // the end of the queue now.
    // However, since duration to retain after discard = 15 000 ms, we need to retain at least the
    // first 2 chunks
    int newSize = adaptiveTrackSelection.evaluateQueueSize(0, queue);
    assertThat(newSize).isEqualTo(2);
  }

  private AdaptiveTrackSelection adaptiveTrackSelection(TrackGroup trackGroup) {
    return adaptiveTrackSelectionWithMinDurationForQualityIncreaseMs(
        trackGroup, AdaptiveTrackSelection.DEFAULT_MIN_DURATION_FOR_QUALITY_INCREASE_MS);
  }

  private AdaptiveTrackSelection adaptiveTrackSelectionWithMinDurationForQualityIncreaseMs(
      TrackGroup trackGroup, long minDurationForQualityIncreaseMs) {
    return prepareTrackSelection(
        new AdaptiveTrackSelection(
            trackGroup,
            selectedAllTracksInGroup(trackGroup),
            mockBandwidthMeter,
            minDurationForQualityIncreaseMs,
            AdaptiveTrackSelection.DEFAULT_MAX_DURATION_FOR_QUALITY_DECREASE_MS,
            AdaptiveTrackSelection.DEFAULT_MIN_DURATION_TO_RETAIN_AFTER_DISCARD_MS,
            /* bandwidthFraction= */ 1.0f,
            AdaptiveTrackSelection.DEFAULT_BUFFERED_FRACTION_TO_LIVE_EDGE_FOR_QUALITY_INCREASE,
            AdaptiveTrackSelection.DEFAULT_MIN_TIME_BETWEEN_BUFFER_REEVALUTATION_MS,
            fakeClock));
  }

  private AdaptiveTrackSelection adaptiveTrackSelectionWithMaxDurationForQualityDecreaseMs(
      TrackGroup trackGroup, long maxDurationForQualityDecreaseMs) {
    return prepareTrackSelection(
        new AdaptiveTrackSelection(
            trackGroup,
            selectedAllTracksInGroup(trackGroup),
            mockBandwidthMeter,
            AdaptiveTrackSelection.DEFAULT_MIN_DURATION_FOR_QUALITY_INCREASE_MS,
            maxDurationForQualityDecreaseMs,
            AdaptiveTrackSelection.DEFAULT_MIN_DURATION_TO_RETAIN_AFTER_DISCARD_MS,
            /* bandwidthFraction= */ 1.0f,
            AdaptiveTrackSelection.DEFAULT_BUFFERED_FRACTION_TO_LIVE_EDGE_FOR_QUALITY_INCREASE,
            AdaptiveTrackSelection.DEFAULT_MIN_TIME_BETWEEN_BUFFER_REEVALUTATION_MS,
            fakeClock));
  }

  private AdaptiveTrackSelection adaptiveTrackSelectionWithMinTimeBetweenBufferReevaluationMs(
      TrackGroup trackGroup,
      long durationToRetainAfterDiscardMs,
      long minTimeBetweenBufferReevaluationMs) {
    return prepareTrackSelection(
        new AdaptiveTrackSelection(
            trackGroup,
            selectedAllTracksInGroup(trackGroup),
            mockBandwidthMeter,
            AdaptiveTrackSelection.DEFAULT_MIN_DURATION_FOR_QUALITY_INCREASE_MS,
            AdaptiveTrackSelection.DEFAULT_MAX_DURATION_FOR_QUALITY_DECREASE_MS,
            durationToRetainAfterDiscardMs,
            /* bandwidthFraction= */ 1.0f,
            AdaptiveTrackSelection.DEFAULT_BUFFERED_FRACTION_TO_LIVE_EDGE_FOR_QUALITY_INCREASE,
            minTimeBetweenBufferReevaluationMs,
            fakeClock));
  }

  private AdaptiveTrackSelection prepareTrackSelection(
      AdaptiveTrackSelection adaptiveTrackSelection) {
    adaptiveTrackSelection.enable();
    adaptiveTrackSelection.updateSelectedTrack(
        /* playbackPositionUs= */ 0,
        /* bufferedDurationUs= */ 0,
        /* availableDurationUs= */ C.TIME_UNSET,
        /* queue= */ Collections.emptyList(),
        /* mediaChunkIterators= */ THREE_EMPTY_MEDIA_CHUNK_ITERATORS);
    return adaptiveTrackSelection;
  }

  private int[] selectedAllTracksInGroup(TrackGroup trackGroup) {
    int[] listIndices = new int[trackGroup.length];
    for (int i = 0; i < trackGroup.length; i++) {
      listIndices[i] = i;
    }
    return listIndices;
  }

  private static Format videoFormat(int bitrate, int width, int height) {
    return Format.createVideoSampleFormat(
        /* id= */ null,
        /* sampleMimeType= */ MimeTypes.VIDEO_H264,
        /* codecs= */ null,
        /* bitrate= */ bitrate,
        /* maxInputSize= */ Format.NO_VALUE,
        /* width= */ width,
        /* height= */ height,
        /* frameRate= */ Format.NO_VALUE,
        /* initializationData= */ null,
        /* drmInitData= */ null);
  }

}