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Move AudioTrack initialization into handleBuffer.
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Move initialization code from the audio renderers into handleBuffer. The audio
session id and tunneling enabled state can be altered using new setters.

This change is not intended to change the behavior of the audio renderers.
Before this change, the AudioTrack would always be reinitialized by the
renderers before calling handleBuffer.

Add a protected onAudioTrackUnderrun method for custom renderers that want to
implement custom handling of underruns.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=144067149
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@andrewlewis @ojw28
andrewlewis authored and ojw28 committed Jan 13, 2017
1 parent 5c89bbe commit ce03b8c
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Showing 3 changed files with 174 additions and 143 deletions.
165 changes: 94 additions & 71 deletions library/src/main/java/com/google/android/exoplayer2/audio/AudioTrack.java
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Original file line number Diff line number Diff line change
Expand Up @@ -38,21 +38,21 @@
* playback position smoothing, non-blocking writes and reconfiguration.
* <p>
* Before starting playback, specify the input format by calling
* {@link #configure(String, int, int, int, int)}. Next call {@link #initialize(int)} or
* {@link #initializeV21(int, boolean)}, optionally specifying an audio session and whether the
* track is to be used with tunneling video playback.
* {@link #configure(String, int, int, int, int)}. Optionally call {@link #setAudioSessionId(int)},
* {@link #setTunnelingEnabledV21(boolean)} and {@link #setStreamType(int)} to configure audio
* playback. These methods may be called after writing data to the track, in which case it will be
* reinitialized as required.
* <p>
* Call {@link #handleBuffer(ByteBuffer, long)} to write data, and {@link #handleDiscontinuity()}
* when the data being fed is discontinuous. Call {@link #play()} to start playing the written data.
* <p>
* Call {@link #configure(String, int, int, int, int)} whenever the input format changes. If
* {@link #isInitialized()} returns {@code false} after the call, it is necessary to call
* {@link #initialize(int)} or {@link #initializeV21(int, boolean)} before writing more data.
* Call {@link #configure(String, int, int, int, int)} whenever the input format changes. The track
* will be reinitialized on the next call to {@link #handleBuffer(ByteBuffer, long)}.
* <p>
* The underlying {@link android.media.AudioTrack} is created by {@link #initialize(int)} and
* released by {@link #reset()} (and {@link #configure(String, int, int, int, int)} unless the input
* format is unchanged). It is safe to call {@link #initialize(int)} or
* {@link #initializeV21(int, boolean)} after calling {@link #reset()} without reconfiguration.
* Calling {@link #reset()} releases the underlying {@link android.media.AudioTrack} (and so does
* calling {@link #configure(String, int, int, int, int)} unless the format is unchanged). It is
* safe to call {@link #handleBuffer(ByteBuffer, long)} after {@link #reset()} without calling
* {@link #configure(String, int, int, int, int)}.
* <p>
* Call {@link #release()} when the instance is no longer required.
*/
Expand All @@ -74,6 +74,13 @@ public interface Listener {
*/
void onUnderrun(int bufferSize, long bufferSizeMs, long elapsedSinceLastFeedMs);

/**
* Called when the audio track has been initialized with the specified {@code audioSessionId}.
*
* @param audioSessionId The audio session id.
*/
void onAudioSessionId(int audioSessionId);

}

/**
Expand Down Expand Up @@ -253,7 +260,7 @@ public InvalidAudioTrackTimestampException(String detailMessage) {
private final AudioTrackUtil audioTrackUtil;

/**
* Used to keep the audio session active on pre-V21 builds (see {@link #initialize(int)}).
* Used to keep the audio session active on pre-V21 builds (see {@link #initialize()}).
*/
private android.media.AudioTrack keepSessionIdAudioTrack;

Expand Down Expand Up @@ -299,6 +306,9 @@ public InvalidAudioTrackTimestampException(String detailMessage) {
private ByteBuffer resampledBuffer;
private boolean useResampledBuffer;

private boolean playing;
private int audioSessionId;
private boolean tunneling;
private boolean hasData;
private long lastFeedElapsedRealtimeMs;

Expand Down Expand Up @@ -329,6 +339,7 @@ public AudioTrack(AudioCapabilities audioCapabilities, Listener listener) {
volume = 1.0f;
startMediaTimeState = START_NOT_SET;
streamType = C.STREAM_TYPE_DEFAULT;
audioSessionId = C.AUDIO_SESSION_ID_UNSET;
}

/**
Expand All @@ -342,14 +353,6 @@ public boolean isPassthroughSupported(String mimeType) {
&& audioCapabilities.supportsEncoding(getEncodingForMimeType(mimeType));
}

/**
* Returns whether the audio track has been successfully initialized via {@link #initialize} or
* {@link #initializeV21(int, boolean)}, and has not yet been {@link #reset}.
*/
public boolean isInitialized() {
return audioTrack != null;
}

/**
* Returns the playback position in the stream starting at zero, in microseconds, or
* {@link #CURRENT_POSITION_NOT_SET} if it is not yet available.
Expand Down Expand Up @@ -512,31 +515,7 @@ public void configure(String mimeType, int channelCount, int sampleRate,
bufferSizeUs = passthrough ? C.TIME_UNSET : framesToDurationUs(pcmBytesToFrames(bufferSize));
}

/**
* Initializes the audio track for writing new buffers using {@link #handleBuffer}.
*
* @param sessionId Audio track session identifier, or {@link C#AUDIO_SESSION_ID_UNSET} to create
* one.
* @return The audio track session identifier.
*/
public int initialize(int sessionId) throws InitializationException {
return initializeInternal(sessionId, false);
}

/**
* Initializes the audio track for writing new buffers using {@link #handleBuffer}.
*
* @param sessionId Audio track session identifier, or {@link C#AUDIO_SESSION_ID_UNSET} to create
* one.
* @param tunneling Whether the audio track is to be used with tunneling video playback.
* @return The audio track session identifier.
*/
public int initializeV21(int sessionId, boolean tunneling) throws InitializationException {
Assertions.checkState(Util.SDK_INT >= 21);
return initializeInternal(sessionId, tunneling);
}

private int initializeInternal(int sessionId, boolean tunneling) throws InitializationException {
private void initialize() throws InitializationException {
// If we're asynchronously releasing a previous audio track then we block until it has been
// released. This guarantees that we cannot end up in a state where we have multiple audio
// track instances. Without this guarantee it would be possible, in extreme cases, to exhaust
Expand All @@ -547,24 +526,24 @@ private int initializeInternal(int sessionId, boolean tunneling) throws Initiali
useHwAvSync = tunneling;
if (useHwAvSync) {
audioTrack = createHwAvSyncAudioTrackV21(sampleRate, channelConfig, targetEncoding,
bufferSize, sessionId);
} else if (sessionId == C.AUDIO_SESSION_ID_UNSET) {
bufferSize, audioSessionId);
} else if (audioSessionId == C.AUDIO_SESSION_ID_UNSET) {
audioTrack = new android.media.AudioTrack(streamType, sampleRate, channelConfig,
targetEncoding, bufferSize, MODE_STREAM);
} else {
// Re-attach to the same audio session.
audioTrack = new android.media.AudioTrack(streamType, sampleRate, channelConfig,
targetEncoding, bufferSize, MODE_STREAM, sessionId);
targetEncoding, bufferSize, MODE_STREAM, audioSessionId);
}
checkAudioTrackInitialized();

sessionId = audioTrack.getAudioSessionId();
int audioSessionId = audioTrack.getAudioSessionId();
if (enablePreV21AudioSessionWorkaround) {
if (Util.SDK_INT < 21) {
// The workaround creates an audio track with a two byte buffer on the same session, and
// does not release it until this object is released, which keeps the session active.
if (keepSessionIdAudioTrack != null
&& sessionId != keepSessionIdAudioTrack.getAudioSessionId()) {
&& audioSessionId != keepSessionIdAudioTrack.getAudioSessionId()) {
releaseKeepSessionIdAudioTrack();
}
if (keepSessionIdAudioTrack == null) {
Expand All @@ -573,21 +552,25 @@ private int initializeInternal(int sessionId, boolean tunneling) throws Initiali
@C.PcmEncoding int encoding = C.ENCODING_PCM_16BIT;
int bufferSize = 2; // Use a two byte buffer, as it is not actually used for playback.
keepSessionIdAudioTrack = new android.media.AudioTrack(streamType, sampleRate,
channelConfig, encoding, bufferSize, MODE_STATIC, sessionId);
channelConfig, encoding, bufferSize, MODE_STATIC, audioSessionId);
}
}
}
if (this.audioSessionId != audioSessionId) {
this.audioSessionId = audioSessionId;
listener.onAudioSessionId(audioSessionId);
}

audioTrackUtil.reconfigure(audioTrack, needsPassthroughWorkarounds());
setAudioTrackVolume();
setVolumeInternal();
hasData = false;
return sessionId;
}

/**
* Starts or resumes playing audio if the audio track has been initialized.
*/
public void play() {
playing = true;
if (isInitialized()) {
resumeSystemTimeUs = System.nanoTime() / 1000;
audioTrack.play();
Expand Down Expand Up @@ -622,9 +605,18 @@ public void handleDiscontinuity() {
* @return A bit field with {@link #RESULT_BUFFER_CONSUMED} if the buffer can be released, and
* {@link #RESULT_POSITION_DISCONTINUITY} if the buffer was not contiguous with previously
* written data.
* @throws InitializationException If an error occurs initializing the track.
* @throws WriteException If an error occurs writing the audio data.
*/
public int handleBuffer(ByteBuffer buffer, long presentationTimeUs) throws WriteException {
public int handleBuffer(ByteBuffer buffer, long presentationTimeUs)
throws InitializationException, WriteException {
if (!isInitialized()) {
initialize();
if (playing) {
play();
}
}

boolean hadData = hasData;
hasData = hasPendingData();
if (hadData && !hasData && audioTrack.getPlayState() != PLAYSTATE_STOPPED) {
Expand Down Expand Up @@ -785,28 +777,52 @@ public void setPlaybackParams(PlaybackParams playbackParams) {

/**
* Sets the stream type for audio track. If the stream type has changed and if the audio track
* is not configured for use with video tunneling, then the audio track is reset and the caller
* must re-initialize the audio track before writing more data. The caller must not reuse the
* audio session identifier when re-initializing with a new stream type.
* is not configured for use with video tunneling, then the audio track is reset and will be
* reinitialized on the next call to {@link #handleBuffer(ByteBuffer, long)}. An audio session
* cannot be reused after a change of stream type, so the audio session identifier will be reset.
* <p>
* If the audio track is configured for use with video tunneling then the stream type is ignored
* and the audio track is not reset. The passed stream type will be used if the audio track is
* later re-configured into non-tunneled mode.
*
* @param streamType The {@link C.StreamType} to use for audio output.
* @return Whether the audio track was reset as a result of this call.
*/
public boolean setStreamType(@C.StreamType int streamType) {
public void setStreamType(@C.StreamType int streamType) {
if (this.streamType == streamType) {
return false;
return;
}
this.streamType = streamType;
if (useHwAvSync) {
// The stream type is ignored in tunneling mode, so no need to reset.
return false;
return;
}
reset();
return true;
audioSessionId = C.AUDIO_SESSION_ID_UNSET;
}

/**
* Sets the audio session id, and resets the audio track if the audio session id has changed.
*/
public void setAudioSessionId(int audioSessionId) {
if (this.audioSessionId != audioSessionId) {
this.audioSessionId = audioSessionId;
reset();
}
}

/**
* Sets whether tunneling is enabled. Enabling tunneling requires platform API version 21 onwards.
* Resets the audio track if tunneling was enabled/disabled.
*
* @param tunneling Whether the audio track will be used with tunneling video playback.
* @throws IllegalStateException Thrown if enabling tunneling on platform API version < 21.
*/
public void setTunnelingEnabledV21(boolean tunneling) {
if (this.tunneling != tunneling) {
Assertions.checkState(Util.SDK_INT >= 21);
this.tunneling = tunneling;
reset();
}
}

/**
Expand All @@ -817,24 +833,25 @@ public boolean setStreamType(@C.StreamType int streamType) {
public void setVolume(float volume) {
if (this.volume != volume) {
this.volume = volume;
setAudioTrackVolume();
setVolumeInternal();
}
}

private void setAudioTrackVolume() {
private void setVolumeInternal() {
if (!isInitialized()) {
// Do nothing.
} else if (Util.SDK_INT >= 21) {
setAudioTrackVolumeV21(audioTrack, volume);
setVolumeInternalV21(audioTrack, volume);
} else {
setAudioTrackVolumeV3(audioTrack, volume);
setVolumeInternalV3(audioTrack, volume);
}
}

/**
* Pauses playback.
*/
public void pause() {
playing = false;
if (isInitialized()) {
resetSyncParams();
audioTrackUtil.pause();
Expand All @@ -844,9 +861,9 @@ public void pause() {
/**
* Releases the underlying audio track asynchronously.
* <p>
* Calling {@link #initialize(int)} or {@link #initializeV21(int, boolean)} will block until the
* audio track has been released, so it is safe to initialize immediately after a reset. The audio
* session may remain active until {@link #release()} is called.
* Calling {@link #handleBuffer(ByteBuffer, long)} will block until the audio track has been
* released, so it is safe to use the audio track immediately after a reset. The audio session may
* remain active until {@link #release()} is called.
*/
public void reset() {
if (isInitialized()) {
Expand Down Expand Up @@ -887,6 +904,8 @@ public void run() {
public void release() {
reset();
releaseKeepSessionIdAudioTrack();
audioSessionId = C.AUDIO_SESSION_ID_UNSET;
playing = false;
}

/**
Expand Down Expand Up @@ -1024,6 +1043,10 @@ private void checkAudioTrackInitialized() throws InitializationException {
throw new InitializationException(state, sampleRate, channelConfig, bufferSize);
}

private boolean isInitialized() {
return audioTrack != null;
}

private long pcmBytesToFrames(long byteCount) {
return byteCount / pcmFrameSize;
}
Expand Down Expand Up @@ -1240,12 +1263,12 @@ private int writeNonBlockingWithAvSyncV21(android.media.AudioTrack audioTrack,
}

@TargetApi(21)
private static void setAudioTrackVolumeV21(android.media.AudioTrack audioTrack, float volume) {
private static void setVolumeInternalV21(android.media.AudioTrack audioTrack, float volume) {
audioTrack.setVolume(volume);
}

@SuppressWarnings("deprecation")
private static void setAudioTrackVolumeV3(android.media.AudioTrack audioTrack, float volume) {
private static void setVolumeInternalV3(android.media.AudioTrack audioTrack, float volume) {
audioTrack.setStereoVolume(volume, volume);
}

Expand Down Expand Up @@ -1494,7 +1517,7 @@ public void setPlaybackParams(PlaybackParams playbackParams) {
playbackParams = (playbackParams != null ? playbackParams : new PlaybackParams())
.allowDefaults();
this.playbackParams = playbackParams;
this.playbackSpeed = playbackParams.getSpeed();
playbackSpeed = playbackParams.getSpeed();
maybeApplyPlaybackParams();
}

Expand Down
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