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Fix AudioTrackPositionTracker logic for playback speed adjustments

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The AudioTrackPositionTracker needs to correct positions by
the speed set on the AudioTrack itself whenever it makes
estimations based on real-time (=the real-time playout
duration is not equal to the media duration played).

This happens for the main playback path already, but not for
the mode in which the position is estimated from the playback
head position and also not in the phase after the track has
been stopped. Both cases are not very noticeable during
normal playback, but become relevant when playing in offload
mode.

PiperOrigin-RevId: 507736408
This commit is contained in:
tonihei 2023-02-07 12:06:49 +00:00 committed by microkatz
parent cccb2f07b7
commit 01d7bc7279
1 changed files with 10 additions and 3 deletions
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13
libraries/exoplayer/src/main/java/androidx/media3/exoplayer/audio/AudioTrackPositionTracker.java
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@ -253,6 +253,7 @@ import java.lang.reflect.Method;
if (audioTimestampPoller != null) {
audioTimestampPoller.reset();
}
resetSyncParams();
}
public long getCurrentPositionUs(boolean sourceEnded) {
@ -282,7 +283,9 @@ import java.lang.reflect.Method;
// getPlaybackHeadPositionUs() only has a granularity of ~20 ms, so we base the position off
// the system clock (and a smoothed offset between it and the playhead position) so as to
// prevent jitter in the reported positions.
positionUs = systemTimeUs + smoothedPlayheadOffsetUs;
positionUs =
Util.getMediaDurationForPlayoutDuration(
systemTimeUs + smoothedPlayheadOffsetUs, audioTrackPlaybackSpeed);
}
if (!sourceEnded) {
positionUs = max(0, positionUs - latencyUs);
@ -452,7 +455,9 @@ import java.lang.reflect.Method;
long systemTimeUs = System.nanoTime() / 1000;
if (systemTimeUs - lastPlayheadSampleTimeUs >= MIN_PLAYHEAD_OFFSET_SAMPLE_INTERVAL_US) {
// Take a new sample and update the smoothed offset between the system clock and the playhead.
playheadOffsets[nextPlayheadOffsetIndex] = playbackPositionUs - systemTimeUs;
playheadOffsets[nextPlayheadOffsetIndex] =
Util.getPlayoutDurationForMediaDuration(playbackPositionUs, audioTrackPlaybackSpeed)
- systemTimeUs;
nextPlayheadOffsetIndex = (nextPlayheadOffsetIndex + 1) % MAX_PLAYHEAD_OFFSET_COUNT;
if (playheadOffsetCount < MAX_PLAYHEAD_OFFSET_COUNT) {
playheadOffsetCount++;
@ -580,7 +585,9 @@ import java.lang.reflect.Method;
if (stopTimestampUs != C.TIME_UNSET) {
// Simulate the playback head position up to the total number of frames submitted.
long elapsedTimeSinceStopUs = (SystemClock.elapsedRealtime() * 1000) - stopTimestampUs;
long framesSinceStop = (elapsedTimeSinceStopUs * outputSampleRate) / C.MICROS_PER_SECOND;
long mediaTimeSinceStopUs =
Util.getMediaDurationForPlayoutDuration(elapsedTimeSinceStopUs, audioTrackPlaybackSpeed);
long framesSinceStop = (mediaTimeSinceStopUs * outputSampleRate) / C.MICROS_PER_SECOND;
return min(endPlaybackHeadPosition, stopPlaybackHeadPosition + framesSinceStop);
}