andrewlewis
Oliver Woodman
parent
d11778dbc8
commit
578abccf16
@ -4,6 +4,8 @@
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* Add `ResolvingDataSource` for just-in-time resolution of `DataSpec`s
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([#5779](https://github.com/google/ExoPlayer/issues/5779)).
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* Add `SilenceMediaSource` that can be used to play silence of a given
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duration ([#5735](https://github.com/google/ExoPlayer/issues/5735)).
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* Subtitles:
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* CEA-608: Handle XDS and TEXT modes
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([#5807](https://github.com/google/ExoPlayer/pull/5807)).
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@ -0,0 +1,242 @@
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/*
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* Copyright (C) 2019 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.android.exoplayer2.source;
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import androidx.annotation.Nullable;
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import com.google.android.exoplayer2.C;
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import com.google.android.exoplayer2.Format;
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import com.google.android.exoplayer2.FormatHolder;
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import com.google.android.exoplayer2.SeekParameters;
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import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
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import com.google.android.exoplayer2.trackselection.TrackSelection;
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import com.google.android.exoplayer2.upstream.Allocator;
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import com.google.android.exoplayer2.upstream.TransferListener;
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import com.google.android.exoplayer2.util.Assertions;
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import com.google.android.exoplayer2.util.MimeTypes;
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import com.google.android.exoplayer2.util.Util;
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import java.util.ArrayList;
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import org.checkerframework.checker.nullness.compatqual.NullableType;
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/** Media source with a single period consisting of silent raw audio of a given duration. */
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public final class SilenceMediaSource extends BaseMediaSource {
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private static final int SAMPLE_RATE_HZ = 44100;
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@C.PcmEncoding private static final int ENCODING = C.ENCODING_PCM_16BIT;
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private static final int CHANNEL_COUNT = 2;
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private static final Format FORMAT =
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Format.createAudioSampleFormat(
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/* id=*/ null,
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MimeTypes.AUDIO_RAW,
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/* codecs= */ null,
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/* bitrate= */ Format.NO_VALUE,
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/* maxInputSize= */ Format.NO_VALUE,
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CHANNEL_COUNT,
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SAMPLE_RATE_HZ,
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ENCODING,
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/* initializationData= */ null,
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/* drmInitData= */ null,
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/* selectionFlags= */ 0,
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/* language= */ null);
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private static final byte[] SILENCE_SAMPLE =
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new byte[Util.getPcmFrameSize(ENCODING, CHANNEL_COUNT) * 1024];
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private final long durationUs;
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/**
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* Creates a new media source providing silent audio of the given duration.
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*
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* @param durationUs The duration of silent audio to output, in microseconds.
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*/
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public SilenceMediaSource(long durationUs) {
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Assertions.checkArgument(durationUs >= 0);
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this.durationUs = durationUs;
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}
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@Override
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public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
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refreshSourceInfo(
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new SinglePeriodTimeline(durationUs, /* isSeekable= */ true, /* isDynamic= */ false),
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/* manifest= */ null);
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}
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@Override
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public void maybeThrowSourceInfoRefreshError() {}
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@Override
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public MediaPeriod createPeriod(MediaPeriodId id, Allocator allocator, long startPositionUs) {
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return new SilenceMediaPeriod(durationUs);
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}
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@Override
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public void releasePeriod(MediaPeriod mediaPeriod) {}
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@Override
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public void releaseSourceInternal() {}
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private static final class SilenceMediaPeriod implements MediaPeriod {
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private static final TrackGroupArray TRACKS = new TrackGroupArray(new TrackGroup(FORMAT));
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private final long durationUs;
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private final ArrayList<SampleStream> sampleStreams;
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public SilenceMediaPeriod(long durationUs) {
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this.durationUs = durationUs;
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sampleStreams = new ArrayList<>();
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}
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@Override
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public void prepare(Callback callback, long positionUs) {
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callback.onPrepared(/* mediaPeriod= */ this);
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}
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@Override
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public void maybeThrowPrepareError() {}
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@Override
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public TrackGroupArray getTrackGroups() {
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return TRACKS;
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}
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@Override
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public long selectTracks(
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@NullableType TrackSelection[] selections,
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boolean[] mayRetainStreamFlags,
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@NullableType SampleStream[] streams,
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boolean[] streamResetFlags,
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long positionUs) {
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for (int i = 0; i < selections.length; i++) {
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if (streams[i] != null && (selections[i] == null || !mayRetainStreamFlags[i])) {
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sampleStreams.remove(streams[i]);
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streams[i] = null;
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}
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if (streams[i] == null && selections[i] != null) {
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SilenceSampleStream stream = new SilenceSampleStream(durationUs);
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stream.seekTo(positionUs);
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sampleStreams.add(stream);
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streams[i] = stream;
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streamResetFlags[i] = true;
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}
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}
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return positionUs;
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}
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@Override
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public void discardBuffer(long positionUs, boolean toKeyframe) {}
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@Override
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public long readDiscontinuity() {
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return C.TIME_UNSET;
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}
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@Override
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public long seekToUs(long positionUs) {
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for (int i = 0; i < sampleStreams.size(); i++) {
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((SilenceSampleStream) sampleStreams.get(i)).seekTo(positionUs);
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}
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return positionUs;
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}
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@Override
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public long getAdjustedSeekPositionUs(long positionUs, SeekParameters seekParameters) {
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return positionUs;
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}
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@Override
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public long getBufferedPositionUs() {
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return C.TIME_END_OF_SOURCE;
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}
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@Override
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public long getNextLoadPositionUs() {
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return C.TIME_END_OF_SOURCE;
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}
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@Override
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public boolean continueLoading(long positionUs) {
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return false;
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}
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@Override
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public void reevaluateBuffer(long positionUs) {}
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}
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private static final class SilenceSampleStream implements SampleStream {
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private final long durationBytes;
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private boolean sentFormat;
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private long positionBytes;
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public SilenceSampleStream(long durationUs) {
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durationBytes = getAudioByteCount(durationUs);
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seekTo(0);
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}
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public void seekTo(long positionUs) {
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positionBytes = getAudioByteCount(positionUs);
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}
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@Override
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public boolean isReady() {
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return true;
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}
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@Override
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public void maybeThrowError() {}
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@Override
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public int readData(
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FormatHolder formatHolder, DecoderInputBuffer buffer, boolean formatRequired) {
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if (!sentFormat || formatRequired) {
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formatHolder.format = FORMAT;
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sentFormat = true;
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return C.RESULT_FORMAT_READ;
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}
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long bytesRemaining = durationBytes - positionBytes;
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if (bytesRemaining == 0) {
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buffer.addFlag(C.BUFFER_FLAG_END_OF_STREAM);
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return C.RESULT_BUFFER_READ;
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}
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int bytesToWrite = (int) Math.min(SILENCE_SAMPLE.length, bytesRemaining);
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buffer.ensureSpaceForWrite(bytesToWrite);
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buffer.addFlag(C.BUFFER_FLAG_KEY_FRAME);
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buffer.data.put(SILENCE_SAMPLE, /* offset= */ 0, bytesToWrite);
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buffer.timeUs = getAudioPositionUs(positionBytes);
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positionBytes += bytesToWrite;
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return C.RESULT_BUFFER_READ;
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}
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@Override
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public int skipData(long positionUs) {
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long oldPositionBytes = positionBytes;
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seekTo(positionUs);
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return (int) ((positionBytes - oldPositionBytes) / SILENCE_SAMPLE.length);
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}
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}
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private static long getAudioByteCount(long durationUs) {
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long audioSampleCount = durationUs * SAMPLE_RATE_HZ / C.MICROS_PER_SECOND;
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return Util.getPcmFrameSize(ENCODING, CHANNEL_COUNT) * audioSampleCount;
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}
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private static long getAudioPositionUs(long bytes) {
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long audioSampleCount = bytes / Util.getPcmFrameSize(ENCODING, CHANNEL_COUNT);
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return audioSampleCount * C.MICROS_PER_SECOND / SAMPLE_RATE_HZ;
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}
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}
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