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authorJames Dong <jdong@google.com>2010-08-16 15:18:13 -0700
committerAndroid Git Automerger <android-git-automerger@android.com>2010-08-16 15:18:13 -0700
commit4ad5c707fa1501f8aba1391cb79306d49ba66272 (patch)
tree04129dd0d215e84ab7192ba5b3ebf3a4b78ebbff /media
parent2565c5b6ef6c9020e8c4b9454ea9ac1b92bdf390 (diff)
parent4fc2c9280c5262c835a4eb78961241de105313c1 (diff)
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am 4fc2c928: am b7208196: Use audio clock as the reference media clock
Merge commit '4fc2c9280c5262c835a4eb78961241de105313c1' * commit '4fc2c9280c5262c835a4eb78961241de105313c1': Use audio clock as the reference media clock
Diffstat (limited to 'media')
-rw-r--r--media/libstagefright/MPEG4Writer.cpp65
1 files changed, 65 insertions, 0 deletions
diff --git a/media/libstagefright/MPEG4Writer.cpp b/media/libstagefright/MPEG4Writer.cpp
index 1460f37..9fe3864 100644
--- a/media/libstagefright/MPEG4Writer.cpp
+++ b/media/libstagefright/MPEG4Writer.cpp
@@ -72,6 +72,11 @@ private:
bool mIsAudio;
bool mIsMPEG4;
int64_t mTrackDurationUs;
+
+ // For realtime applications, we need to adjust the media clock
+ // for video track based on the audio media clock
+ bool mIsRealTimeRecording;
+ int64_t mMaxTimeStampUs;
int64_t mEstimatedTrackSizeBytes;
int64_t mMaxWriteTimeUs;
int32_t mTimeScale;
@@ -940,6 +945,7 @@ status_t MPEG4Writer::startWriterThread() {
mDone = false;
mIsFirstChunk = true;
+ mDriftTimeUs = 0;
for (List<Track *>::iterator it = mTracks.begin();
it != mTracks.end(); ++it) {
ChunkInfo info;
@@ -967,6 +973,14 @@ status_t MPEG4Writer::Track::start(MetaData *params) {
startTimeUs = 0;
}
+ mIsRealTimeRecording = true;
+ {
+ int32_t isNotRealTime;
+ if (params && params->findInt32(kKeyNotRealTime, &isNotRealTime)) {
+ mIsRealTimeRecording = (isNotRealTime == 0);
+ }
+ }
+
initTrackingProgressStatus(params);
sp<MetaData> meta = new MetaData;
@@ -1326,6 +1340,10 @@ void MPEG4Writer::Track::threadEntry() {
uint32_t previousSampleSize = 0; // Size of the previous sample
int64_t previousPausedDurationUs = 0;
int64_t timestampUs;
+
+ int64_t wallClockTimeUs = 0;
+ int64_t lastWallClockTimeUs = 0;
+
sp<MetaData> meta_data;
bool collectStats = collectStatisticalData();
@@ -1429,6 +1447,33 @@ void MPEG4Writer::Track::threadEntry() {
}
timestampUs -= previousPausedDurationUs;
+ if (mIsRealTimeRecording && !mIsAudio) {
+ // The minor adjustment on the timestamp is heuristic/experimental
+ // We are adjusting the timestamp to reduce the fluctuation of the duration
+ // of neighboring samples. This in turn helps reduce the track header size,
+ // especially, the number of entries in the "stts" box.
+ if (mNumSamples > 1) {
+ int64_t durationUs = timestampUs + mOwner->getDriftTimeUs() - lastTimestampUs;
+ int64_t diffUs = (durationUs > lastDurationUs)
+ ? durationUs - lastDurationUs
+ : lastDurationUs - durationUs;
+ if (diffUs <= 5000) { // XXX: Magic number 5ms
+ timestampUs = lastTimestampUs + lastDurationUs;
+ } else {
+ timestampUs += mOwner->getDriftTimeUs();
+ }
+ }
+ }
+ CHECK(timestampUs >= 0);
+ if (mNumSamples > 1) {
+ if (timestampUs <= lastTimestampUs) {
+ LOGW("Drop a frame, since it arrives too late!");
+ copy->release();
+ copy = NULL;
+ continue;
+ }
+ }
+
LOGV("time stamp: %lld and previous paused duration %lld",
timestampUs, previousPausedDurationUs);
if (timestampUs > mTrackDurationUs) {
@@ -1454,6 +1499,14 @@ void MPEG4Writer::Track::threadEntry() {
}
lastDurationUs = timestampUs - lastTimestampUs;
lastTimestampUs = timestampUs;
+ if (mIsRealTimeRecording && mIsAudio) {
+ wallClockTimeUs = systemTime() / 1000;
+ int64_t wallClockDurationUs = wallClockTimeUs - lastWallClockTimeUs;
+ if (mNumSamples > 2) {
+ mOwner->addDriftTimeUs(lastDurationUs - wallClockDurationUs);
+ }
+ lastWallClockTimeUs = wallClockTimeUs;
+ }
if (isSync != 0) {
mStssTableEntries.push_back(mNumSamples);
@@ -1679,6 +1732,18 @@ void MPEG4Writer::Track::logStatisticalData(bool isAudio) {
}
}
+void MPEG4Writer::addDriftTimeUs(int64_t driftTimeUs) {
+ LOGV("addDriftTimeUs: %lld us", driftTimeUs);
+ Mutex::Autolock autolock(mLock);
+ mDriftTimeUs += driftTimeUs;
+}
+
+int64_t MPEG4Writer::getDriftTimeUs() {
+ LOGV("getDriftTimeUs: %lld us", mDriftTimeUs);
+ Mutex::Autolock autolock(mLock);
+ return mDriftTimeUs;
+}
+
void MPEG4Writer::Track::bufferChunk(int64_t timestampUs) {
LOGV("bufferChunk");