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Bug 1333341 - Fix accumulating rounding error in VideoTrackEncoder. r=jesup

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MozReview-Commit-ID: GoVNRqvZPSF

--HG--
extra : rebase_source : dd0faa69ce5fbf193096ba4c8c6078811c548351
This commit is contained in:
Andreas Pehrson 2017-01-24 16:18:48 +01:00
parent 6308603b30
commit efb139cce2
2 changed files with 55 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
dom/media/encoder/TrackEncoder.cpp
View File

@ -317,11 +317,13 @@ VideoTrackEncoder::AppendVideoSegment(const VideoSegment& aSegment)
// Adapt to the time before the first frame. This extends the first frame
// from [start, end] to [0, end], but it'll do for now.
CheckedInt64 diff = FramesToUsecs(nullDuration, mTrackRate);
MOZ_ASSERT(diff.isValid());
if (diff.isValid()) {
mLastChunk.mTimeStamp -= TimeDuration::FromMicroseconds(diff.value());
mLastChunk.mDuration += nullDuration;
if (!diff.isValid()) {
NS_ERROR("null duration overflow");
return NS_ERROR_DOM_MEDIA_OVERFLOW_ERR;
}
mLastChunk.mTimeStamp -= TimeDuration::FromMicroseconds(diff.value());
mLastChunk.mDuration += nullDuration;
}
MOZ_ASSERT(!mLastChunk.IsNull());
@ -357,25 +359,41 @@ VideoTrackEncoder::AppendVideoSegment(const VideoSegment& aSegment)
}
}
TimeDuration diff = chunk.mTimeStamp - mLastChunk.mTimeStamp;
if (diff <= TimeDuration::FromSeconds(0)) {
// The timestamp from mLastChunk is newer than from chunk.
// This means the durations reported from MediaStreamGraph for mLastChunk
// were larger than the timestamp diff - and durations were used to
// trigger the 1-second frame above. This could happen due to drift or
// underruns in the graph.
TRACK_LOG(LogLevel::Warning,
("[VideoTrackEncoder]: Underrun detected. Diff=%.5fs",
diff.ToSeconds()));
chunk.mTimeStamp = mLastChunk.mTimeStamp;
} else {
RefPtr<layers::Image> lastImage = mLastChunk.mFrame.GetImage();
TRACK_LOG(LogLevel::Verbose,
("[VideoTrackEncoder]: Appending video frame %p, duration=%.5f",
lastImage.get(), diff.ToSeconds()));
CheckedInt64 duration = UsecsToFrames(diff.ToMicroseconds(), mTrackRate);
MOZ_ASSERT(duration.isValid());
if (duration.isValid()) {
if (mStartOffset.IsNull()) {
mStartOffset = mLastChunk.mTimeStamp;
}
TimeDuration relativeTime = chunk.mTimeStamp - mStartOffset;
RefPtr<layers::Image> lastImage = mLastChunk.mFrame.GetImage();
TRACK_LOG(LogLevel::Verbose,
("[VideoTrackEncoder]: Appending video frame %p, at pos %.5fs",
lastImage.get(), relativeTime.ToSeconds()));
CheckedInt64 totalDuration =
UsecsToFrames(relativeTime.ToMicroseconds(), mTrackRate);
if (!totalDuration.isValid()) {
NS_ERROR("Duration overflow");
return NS_ERROR_DOM_MEDIA_OVERFLOW_ERR;
}
CheckedInt64 duration = totalDuration - mEncodedTicks;
if (!duration.isValid()) {
NS_ERROR("Duration overflow");
return NS_ERROR_DOM_MEDIA_OVERFLOW_ERR;
}
if (duration.isValid()) {
if (duration.value() <= 0) {
// The timestamp for mLastChunk is newer than for chunk.
// This means the durations reported from MediaStreamGraph for
// mLastChunk were larger than the timestamp diff - and durations were
// used to trigger the 1-second frame above. This could happen due to
// drift or underruns in the graph.
TRACK_LOG(LogLevel::Warning,
("[VideoTrackEncoder]: Underrun detected. Diff=%lld",
duration.value()));
chunk.mTimeStamp = mLastChunk.mTimeStamp;
} else {
mEncodedTicks += duration.value();
mRawSegment.AppendFrame(lastImage.forget(),
duration.value(),
mLastChunk.mFrame.GetIntrinsicSize(),

15
dom/media/encoder/TrackEncoder.h
View File

@ -76,7 +76,7 @@ public:
{
ReentrantMonitorAutoEnter mon(mReentrantMonitor);
mCanceled = true;
mReentrantMonitor.NotifyAll();
NotifyEndOfStream();
}
virtual void SetBitrate(const uint32_t aBitrate) {}
@ -255,6 +255,7 @@ public:
, mDisplayWidth(0)
, mDisplayHeight(0)
, mTrackRate(aTrackRate)
, mEncodedTicks(0)
, mVideoBitrate(0)
{
mLastChunk.mDuration = 0;
@ -349,6 +350,18 @@ protected:
*/
VideoSegment mRawSegment;
/**
* The number of mTrackRate ticks we have passed to the encoder.
* Only accessed in AppendVideoSegment().
*/
StreamTime mEncodedTicks;
/**
* The time of the first real video frame passed to the encoder.
* Only accessed in AppendVideoSegment().
*/
TimeStamp mStartOffset;
uint32_t mVideoBitrate;
};