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Bug 870400 - Calculate audio timestamps for WMF based on audio frames played, rather than trusting the container's timestamps. r=padenot

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This commit is contained in:
Chris Pearce 2013-05-31 11:34:52 +12:00
parent 7f1070c9de
commit f24ba25bbd
2 changed files with 72 additions and 5 deletions
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66
content/media/wmf/WMFReader.cpp
View File

@ -48,10 +48,13 @@ WMFReader::WMFReader(AbstractMediaDecoder* aDecoder)
mVideoWidth(0),
mVideoHeight(0),
mVideoStride(0),
mAudioFrameSum(0),
mAudioFrameOffset(0),
mHasAudio(false),
mHasVideo(false),
mCanSeek(false),
mUseHwAccel(false),
mMustRecaptureAudioPosition(true),
mIsMP3Enabled(WMFDecoder::IsMP3Supported())
{
NS_ASSERTION(NS_IsMainThread(), "Must be on main thread.");
@ -605,6 +608,31 @@ GetSampleDuration(IMFSample* aSample)
return HNsToUsecs(duration);
}
HRESULT
HNsToFrames(int64_t aHNs, uint32_t aRate, int64_t* aOutFrames)
{
MOZ_ASSERT(aOutFrames);
const int64_t HNS_PER_S = USECS_PER_S * 10;
CheckedInt<int64_t> i = aHNs;
i *= aRate;
i /= HNS_PER_S;
NS_ENSURE_TRUE(i.isValid(), E_FAIL);
*aOutFrames = i.value();
return S_OK;
}
HRESULT
FramesToUsecs(int64_t aSamples, uint32_t aRate, int64_t* aOutUsecs)
{
MOZ_ASSERT(aOutUsecs);
CheckedInt<int64_t> i = aSamples;
i *= USECS_PER_S;
i /= aRate;
NS_ENSURE_TRUE(i.isValid(), E_FAIL);
*aOutUsecs = i.value();
return S_OK;
}
bool
WMFReader::DecodeAudioData()
{
@ -660,11 +688,33 @@ WMFReader::DecodeAudioData()
memcpy(pcmSamples.get(), data, currentLength);
buffer->Unlock();
int64_t offset = mDecoder->GetResource()->Tell();
int64_t timestamp = HNsToUsecs(timestampHns);
int64_t duration = GetSampleDuration(sample);
// We calculate the timestamp and the duration based on the number of audio
// frames we've already played. We don't trust the timestamp stored on the
// IMFSample, as sometimes it's wrong, possibly due to buggy encoders?
mAudioQueue.Push(new AudioData(offset,
// If this sample block comes after a discontinuity (i.e. a gap or seek)
// reset the frame counters, and capture the timestamp. Future timestamps
// will be offset from this block's timestamp.
UINT32 discontinuity = false;
sample->GetUINT32(MFSampleExtension_Discontinuity, &discontinuity);
if (mMustRecaptureAudioPosition || discontinuity) {
mAudioFrameSum = 0;
hr = HNsToFrames(timestampHns, mAudioRate, &mAudioFrameOffset);
NS_ENSURE_TRUE(SUCCEEDED(hr), false);
mMustRecaptureAudioPosition = false;
}
int64_t timestamp;
hr = FramesToUsecs(mAudioFrameOffset + mAudioFrameSum, mAudioRate, &timestamp);
NS_ENSURE_TRUE(SUCCEEDED(hr), false);
mAudioFrameSum += numFrames;
int64_t duration;
hr = FramesToUsecs(numFrames, mAudioRate, &duration);
NS_ENSURE_TRUE(SUCCEEDED(hr), false);
mAudioQueue.Push(new AudioData(mDecoder->GetResource()->Tell(),
timestamp,
duration,
numFrames,
@ -901,7 +951,7 @@ WMFReader::DecodeVideoFrame(bool &aKeyframeSkip,
#ifdef LOG_SAMPLE_DECODE
LOG("Decoded video sample timestamp=%lld duration=%lld stride=%d height=%u flags=%u",
timestamp, duration, stride, mVideoHeight, flags);
timestamp, duration, mVideoStride, mVideoHeight, flags);
#endif
if ((flags & MF_SOURCE_READERF_ENDOFSTREAM)) {
@ -930,6 +980,12 @@ WMFReader::Seek(int64_t aTargetUs,
nsresult rv = ResetDecode();
NS_ENSURE_SUCCESS(rv, rv);
// Mark that we must recapture the audio frame count from the next sample.
// WMF doesn't set a discontinuity marker when we seek to time 0, so we
// must remember to recapture the audio frame offset and reset the frame
// sum on the next audio packet we decode.
mMustRecaptureAudioPosition = true;
AutoPropVar var;
HRESULT hr = InitPropVariantFromInt64(UsecsToHNs(aTargetUs), &var);
NS_ENSURE_TRUE(SUCCEEDED(hr), NS_ERROR_FAILURE);

11
content/media/wmf/WMFReader.h
View File

@ -91,6 +91,17 @@ private:
uint32_t mVideoHeight;
uint32_t mVideoStride;
// The offset, in audio frames, at which playback started since the
// last discontinuity.
int64_t mAudioFrameOffset;
// The number of audio frames that we've played since the last
// discontinuity.
int64_t mAudioFrameSum;
// True if we need to re-initialize mAudioFrameOffset and mAudioFrameSum
// from the next audio packet we decode. This happens after a seek, since
// WMF doesn't mark a stream as having a discontinuity after a seek(0).
bool mMustRecaptureAudioPosition;
bool mHasAudio;
bool mHasVideo;
bool mCanSeek;