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Code Issues Releases Wiki Activity

OD FFmpeg: do not attempt to correct stream lag unless a seek was demanded by user

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This commit is contained in:
mchinen 2012-06-01 06:11:45 +00:00
parent 2aedaaa68d
commit 1fb7a1dcee
1 changed files with 25 additions and 7 deletions
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32
src/ondemand/ODDecodeFFmpegTask.cpp
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@ -199,7 +199,6 @@ mNumStreams(numStreams),
mScs(scs), mScs(scs),
mFormatContext(formatContext), mFormatContext(formatContext),
mNumSamplesInCache(0), mNumSamplesInCache(0),
mCurrentPos(0),
mCurrentLen(0), mCurrentLen(0),
mSeekingAllowedStatus(ODFFMPEG_SEEKING_TEST_UNKNOWN), mSeekingAllowedStatus(ODFFMPEG_SEEKING_TEST_UNKNOWN),
mStreamIndex(streamIndex) mStreamIndex(streamIndex)
@ -218,6 +217,13 @@ mStreamIndex(streamIndex)
mChannels[s][c] = channels[s][c]; mChannels[s][c] = channels[s][c];
} }
} }
// get the current stream start time.
int64_t stream_delay = 0;
if (mScs[streamIndex]->m_stream->start_time != int64_t(AV_NOPTS_VALUE) &&
mScs[streamIndex]->m_stream->start_time > 0) {
stream_delay = mScs[streamIndex]->m_stream->start_time;
}
mCurrentPos = double(stream_delay) / AV_TIME_BASE;
//TODO: add a ref counter to scs? This will be necessary if we want to allow copy and paste of not-yet decoded //TODO: add a ref counter to scs? This will be necessary if we want to allow copy and paste of not-yet decoded
//ODDecodeBlockFiles that point to FFmpeg files. //ODDecodeBlockFiles that point to FFmpeg files.
@ -281,7 +287,7 @@ int ODFFmpegDecoder::Decode(samplePtr & data, sampleFormat & format, sampleCount
FillDataFromCache(bufStart, format, start,len,channel); FillDataFromCache(bufStart, format, start,len,channel);
} }
bool seeking = false;
//look at the decoding timestamp and see if the next sample that will be decoded is not the next sample we need. //look at the decoding timestamp and see if the next sample that will be decoded is not the next sample we need.
if(len && (mCurrentPos > start + len || mCurrentPos + kDecodeSampleAllowance < start ) && SeekingAllowed()) { if(len && (mCurrentPos > start + len || mCurrentPos + kDecodeSampleAllowance < start ) && SeekingAllowed()) {
sc = mScs[mStreamIndex]; sc = mScs[mStreamIndex];
@ -310,6 +316,8 @@ int ODFFmpegDecoder::Decode(samplePtr & data, sampleFormat & format, sampleCount
sampleCount actualDecodeStart = 0.5 + st->codec->sample_rate * st->cur_dts * ((double)st->time_base.num/st->time_base.den); //this is mostly safe because den is usually 1 or low number but check for high values. sampleCount actualDecodeStart = 0.5 + st->codec->sample_rate * st->cur_dts * ((double)st->time_base.num/st->time_base.den); //this is mostly safe because den is usually 1 or low number but check for high values.
mCurrentPos = actualDecodeStart; mCurrentPos = actualDecodeStart;
seeking = true;
//if the seek was past our desired position, rewind a bit. //if the seek was past our desired position, rewind a bit.
//printf("seek ok to %llu samps, float: %f\n",actualDecodeStart,actualDecodeStartDouble); //printf("seek ok to %llu samps, float: %f\n",actualDecodeStart,actualDecodeStartDouble);
} else } else
@ -333,13 +341,23 @@ int ODFFmpegDecoder::Decode(samplePtr & data, sampleFormat & format, sampleCount
{ {
nChannels = sc->m_stream->codec->channels < sc->m_initialchannels ? sc->m_stream->codec->channels : sc->m_initialchannels; nChannels = sc->m_stream->codec->channels < sc->m_initialchannels ? sc->m_stream->codec->channels : sc->m_initialchannels;
//find out the dts we've seekd to. can't use the stream->cur_dts because it is faulty. also note that until we do the first seek, pkt.dts can be false and will change for the same samples after the initial seek. //find out the dts we've seekd to. can't use the stream->cur_dts because it is faulty. also note that until we do the first seek, pkt.dts can be false and will change for the same samples after the initial seek.
sampleCount actualDecodeStart = 0.52 + sc->m_stream->codec->sample_rate * sc->m_pkt.dts * ((double)sc->m_stream->time_base.num/sc->m_stream->time_base.den); //this is mostly safe because den is usually 1 or low number but check for high values. sampleCount actualDecodeStart = mCurrentPos;
//hack to get rounding to work to neareset frame size since dts isn't exact // we need adjacent samples, so don't use dts most of the time which will leave gaps between frames
if (sc->m_stream->codec->frame_size) { // for some formats
actualDecodeStart = ((actualDecodeStart + sc->m_stream->codec->frame_size/2) / sc->m_stream->codec->frame_size) * sc->m_stream->codec->frame_size; // The only other case for inserting silence is for initial offset and ImportFFmpeg.cpp does this for us
if (seeking) {
actualDecodeStart = 0.52 + (sc->m_stream->codec->sample_rate * sc->m_pkt.dts
* ((double)sc->m_stream->time_base.num / sc->m_stream->time_base.den));
//this is mostly safe because den is usually 1 or low number but check for high values.
//hack to get rounding to work to neareset frame size since dts isn't exact
if (sc->m_stream->codec->frame_size) {
actualDecodeStart = ((actualDecodeStart + sc->m_stream->codec->frame_size/2) / sc->m_stream->codec->frame_size) * sc->m_stream->codec->frame_size;
}
// reset for the next one
seeking = false;
} }
if(actualDecodeStart != mCurrentPos) if(actualDecodeStart != mCurrentPos)
printf("ts not matching - now:%llu , last:%llu, lastlen:%llu, start %llu, len %llu\n",actualDecodeStart, mCurrentPos, mCurrentLen, start, len); printf("ts not matching - now:%llu , last:%llu, lastlen:%llu, start %llu, len %llu\n",actualDecodeStart, mCurrentPos, mCurrentLen, start, len);
//if we've skipped over some samples, fill the gap with silence. This could happen often in the beginning of the file. //if we've skipped over some samples, fill the gap with silence. This could happen often in the beginning of the file.