Android/frameworks_base
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Merge "Fix track duration calculation if the start timestamp is non-zero" into gingerbread

Browse Source
This commit is contained in:
James Dong
2010-09-27 10:08:52 -07:00
committed by Android (Google) Code Review
parent abaabb2c79 dacebe62c6
commit bf47092e1e
1 changed files with 36 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

39
media/libstagefright/MPEG4Writer.cpp
View File

@@ -1541,20 +1541,52 @@ status_t MPEG4Writer::Track::threadEntry() {
int32_t isSync = false;
meta_data->findInt32(kKeyIsSyncFrame, &isSync);
/*
* The original timestamp found in the data buffer will be modified as below:
*
* There is a playback offset into this track if the track's start time
* is not the same as the movie start time, which will be recorded in edst
* box of the output file. The playback offset is to make sure that the
* starting time of the audio/video tracks are synchronized. Although the
* track's media timestamp may be subject to various modifications
* as outlined below, the track's playback offset time remains unchanged
* once the first data buffer of the track is received.
*
* The media time stamp will be calculated by subtracting the playback offset
* (and potential pause durations) from the original timestamp in the buffer.
*
* If this track is a video track for a real-time recording application with
* both audio and video tracks, its media timestamp will subject to further
* modification based on the media clock of the audio track. This modification
* is needed for the purpose of maintaining good audio/video synchronization.
*
* If the recording session is paused and resumed multiple times, the track
* media timestamp will be modified as if the recording session had never been
* paused at all during playback of the recorded output file. In other words,
* the output file will have no memory of pause/resume durations.
*
*/
CHECK(meta_data->findInt64(kKeyTime, &timestampUs));
LOGV("%s timestampUs: %lld", mIsAudio? "Audio": "Video", timestampUs);
////////////////////////////////////////////////////////////////////////////////
if (mSampleSizes.empty()) {
mStartTimestampUs = timestampUs;
mOwner->setStartTimestampUs(mStartTimestampUs);
previousPausedDurationUs = mStartTimestampUs;
}
if (mResumed) {
previousPausedDurationUs += (timestampUs - mTrackDurationUs - lastDurationUs);
int64_t durExcludingEarlierPausesUs = timestampUs - previousPausedDurationUs;
CHECK(durExcludingEarlierPausesUs >= 0);
int64_t pausedDurationUs = durExcludingEarlierPausesUs - mTrackDurationUs;
CHECK(pausedDurationUs >= lastDurationUs);
previousPausedDurationUs += pausedDurationUs - lastDurationUs;
mResumed = false;
}
timestampUs -= previousPausedDurationUs;
CHECK(timestampUs >= 0);
if (mIsRealTimeRecording && !mIsAudio) {
// The minor adjustment on the timestamp is heuristic/experimental
// We are adjusting the timestamp to reduce the fluctuation of the duration
@@ -1590,8 +1622,8 @@ status_t MPEG4Writer::Track::threadEntry() {
}
}
LOGV("time stamp: %lld and previous paused duration %lld",
timestampUs, previousPausedDurationUs);
LOGV("%s media time stamp: %lld and previous paused duration %lld",
mIsAudio? "Audio": "Video", timestampUs, previousPausedDurationUs);
if (timestampUs > mTrackDurationUs) {
mTrackDurationUs = timestampUs;
}
@@ -1873,6 +1905,7 @@ void MPEG4Writer::Track::writeTrackHeader(
// First elst entry: specify the starting time offset
int64_t offsetUs = mStartTimestampUs - moovStartTimeUs;
LOGV("OffsetUs: %lld", offsetUs);
int32_t seg = (offsetUs * mvhdTimeScale + 5E5) / 1E6;
mOwner->writeInt32(seg); // in mvhd timecale
mOwner->writeInt32(-1); // starting time offset