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Code Issues Releases Wiki Activity

OD FFmpeg: fix a bug with demand seeking by using a safer seek test

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This commit is contained in:
mchinen 2012-06-01 06:11:49 +00:00
parent 1fb7a1dcee
commit c4f1a52413
1 changed files with 29 additions and 7 deletions
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36
src/ondemand/ODDecodeFFmpegTask.cpp
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@ -155,6 +155,7 @@ bool ODFFmpegDecoder::SeekingAllowed()
AVFormatContext* ic = (AVFormatContext*)mFormatContext; AVFormatContext* ic = (AVFormatContext*)mFormatContext;
bool audioStreamExists = false; bool audioStreamExists = false;
AVStream* st; AVStream* st;
//test the audio stream(s) //test the audio stream(s)
for (unsigned int i = 0; i < ic->nb_streams; i++) for (unsigned int i = 0; i < ic->nb_streams; i++)
{ {
@ -177,14 +178,31 @@ bool ODFFmpegDecoder::SeekingAllowed()
goto test_failed; goto test_failed;
//TODO: now try a seek and see if dts/pts (decode/presentation timestamp) is updated as we expected it to be. //TODO: now try a seek and see if dts/pts (decode/presentation timestamp) is updated as we expected it to be.
//This should be done using a new AVFormatContext clone so that we don't ruin the file pointer if we fail. //This should be done using a new AVFormatContext clone so that we don't ruin the file pointer if we fail.
// url_fseek(mFormatContext->pb,0,SEEK_SET); // url_fseek(mFormatContext->pb,0,SEEK_SET);
if(av_seek_frame(mFormatContext,st->index,0,0) >= 0) {
AVFormatContext* tempContext;
int err;
err = ufile_fopen_input(&tempContext, mFName);
if (err < 0)
{
goto test_failed;
}
err = av_find_stream_info(tempContext);
if (err < 0)
{
goto test_failed;
}
if(av_seek_frame(tempContext, st->index, 0, 0) >= 0) {
mSeekingAllowedStatus = ODFFMPEG_SEEKING_TEST_SUCCESS; mSeekingAllowedStatus = ODFFMPEG_SEEKING_TEST_SUCCESS;
if (tempContext) av_close_input_file(tempContext);
return SeekingAllowed(); return SeekingAllowed();
} }
if (tempContext) av_close_input_file(tempContext);
test_failed: test_failed:
mSeekingAllowedStatus = ODFFMPEG_SEEKING_TEST_FAILED; mSeekingAllowedStatus = ODFFMPEG_SEEKING_TEST_FAILED;
return SeekingAllowed(); return SeekingAllowed();
@ -279,7 +297,7 @@ int ODFFmpegDecoder::Decode(samplePtr & data, sampleFormat & format, sampleCount
int nChannels; int nChannels;
printf("start %llu len %llu\n", start, len);
//TODO update this to work with seek - this only works linearly now. //TODO update this to work with seek - this only works linearly now.
if(mCurrentPos > start && mCurrentPos <= start+len + kDecodeSampleAllowance) if(mCurrentPos > start && mCurrentPos <= start+len + kDecodeSampleAllowance)
{ {
@ -302,7 +320,7 @@ int ODFFmpegDecoder::Decode(samplePtr & data, sampleFormat & format, sampleCount
stindex =i; stindex =i;
} }
if(stindex >=0) { if(stindex >=0) {
int numAttempts = 0; int numAttempts = 0;
//reset mCurrentPos to a bogus value //reset mCurrentPos to a bogus value
mCurrentPos = start+len +1; mCurrentPos = start+len +1;
@ -311,6 +329,8 @@ int ODFFmpegDecoder::Decode(samplePtr & data, sampleFormat & format, sampleCount
targetts = (start-kDecodeSampleAllowance*numAttempts/kMaxSeekRewindAttempts) * ((double)st->time_base.den/(st->time_base.num * st->codec->sample_rate )); targetts = (start-kDecodeSampleAllowance*numAttempts/kMaxSeekRewindAttempts) * ((double)st->time_base.den/(st->time_base.num * st->codec->sample_rate ));
if(targetts<0) if(targetts<0)
targetts=0; targetts=0;
printf("attempting seek to %llu, attempts %d\n", targetts, numAttempts);
if(av_seek_frame(mFormatContext,stindex,targetts,0) >= 0){ if(av_seek_frame(mFormatContext,stindex,targetts,0) >= 0){
//find out the dts we've seekd to. //find out the dts we've seekd to.
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.
@ -320,8 +340,10 @@ int ODFFmpegDecoder::Decode(samplePtr & data, sampleFormat & format, sampleCount
//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 {
printf("seek failed");
break; break;
}
} }
if(mCurrentPos>start){ if(mCurrentPos>start){
mSeekingAllowedStatus = ODFFMPEG_SEEKING_TEST_FAILED; mSeekingAllowedStatus = ODFFMPEG_SEEKING_TEST_FAILED;