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== FFMPEG ==

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This fixes a rather subtle seeking issue with ffmpeg and Sony 
XDCAM-footage.

Problem is: MPEG2 streams within an MP4 container can contain a start 
time - at several places. There is a starttime within the video 
and audio streams and one within the container.

FFMpeg commandline tool only uses the container starttime and we used 
the stream starttime. 

The world would be a better place, if those two timestamps always match 
up, since in XDCAM-footage those two starttimes differ in 4 
frames - and the container has the right one.

We now always use the container start time as ffmpeg commandline tool 
does (in the hope, that there is a good explaination for this and this 
is the right thing(tm) to do).

I tested this also with HDV footage, which seems to work with the new 
code, too.

Additional fix: disabled seek_by_bytes again, since it will only work 
correctly, if ffmpeg guessed the HDV bitrate right (which it doesn't). 
If you have seeking issues with HDV and have an older version of ffmpeg 
installed, please upgrade, newer versions have some fixes in them.
This commit is contained in:
Peter Schlaile 2010-11-01 18:13:10 +00:00
parent 3a8c37bb24
commit 1b18ea5823
2 changed files with 23 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
intern/audaspace/ffmpeg/AUD_FFMPEGReader.cpp
View File

@ -246,10 +246,8 @@ void AUD_FFMPEGReader::seek(int position)
{ {
if(position >= 0) if(position >= 0)
{ {
uint64_t st_time = m_formatCtx->streams[m_stream]->start_time; uint64_t st_time = m_formatCtx->start_time;
double time_base = uint64_t seek_pos = position * AV_TIME_BASE / m_specs.rate;
av_q2d(m_formatCtx->streams[m_stream]->time_base);
uint64_t seek_pos = position / time_base / m_specs.rate;
if (seek_pos < 0) { if (seek_pos < 0) {
seek_pos = 0; seek_pos = 0;
@ -259,9 +257,14 @@ void AUD_FFMPEGReader::seek(int position)
seek_pos += st_time; seek_pos += st_time;
} }
double pts_time_base =
av_q2d(m_formatCtx->streams[m_stream]->time_base);
uint64_t pts_st_time =
((st_time != AV_NOPTS_VALUE) ? st_time : 0)
/ pts_time_base / (uint64_t) AV_TIME_BASE;
// a value < 0 tells us that seeking failed // a value < 0 tells us that seeking failed
if(av_seek_frame(m_formatCtx, m_stream, seek_pos, if(av_seek_frame(m_formatCtx, -1, seek_pos,
AVSEEK_FLAG_BACKWARD | AVSEEK_FLAG_ANY) >= 0) AVSEEK_FLAG_BACKWARD | AVSEEK_FLAG_ANY) >= 0)
{ {
avcodec_flush_buffers(m_codecCtx); avcodec_flush_buffers(m_codecCtx);
@ -284,7 +287,7 @@ void AUD_FFMPEGReader::seek(int position)
{ {
// calculate real position, and read to frame! // calculate real position, and read to frame!
m_position = (packet.pts - m_position = (packet.pts -
((st_time != AV_NOPTS_VALUE) ? st_time : 0)) * time_base * m_specs.rate; pts_st_time) * pts_time_base * m_specs.rate;
if(m_position < position) if(m_position < position)
{ {
@ -307,6 +310,7 @@ void AUD_FFMPEGReader::seek(int position)
} }
else else
{ {
fprintf(stderr, "seeking failed!\n");
// Seeking failed, do nothing. // Seeking failed, do nothing.
} }
} }

21
source/blender/imbuf/intern/anim_movie.c
View File

@ -839,7 +839,15 @@ static ImBuf * ffmpeg_fetchibuf(struct anim * anim, int position) {
} }
} }
/* disable seek_by_bytes for now, since bitrates are guessed wrong!
also: MPEG2TS-seeking was fixed in later versions of ffmpeg, so problem
is somewhat fixed by now (until we add correct timecode management code...)
*/
#if 0
seek_by_bytes = !!(anim->pFormatCtx->iformat->flags & AVFMT_TS_DISCONT); seek_by_bytes = !!(anim->pFormatCtx->iformat->flags & AVFMT_TS_DISCONT);
#else
seek_by_bytes = FALSE;
#endif
if (position != anim->curposition + 1) { if (position != anim->curposition + 1) {
#ifdef FFMPEG_OLD_FRAME_RATE #ifdef FFMPEG_OLD_FRAME_RATE
@ -851,12 +859,9 @@ static ImBuf * ffmpeg_fetchibuf(struct anim * anim, int position) {
av_q2d(anim->pFormatCtx->streams[anim->videoStream] av_q2d(anim->pFormatCtx->streams[anim->videoStream]
->r_frame_rate); ->r_frame_rate);
#endif #endif
double time_base = double pts_time_base = av_q2d(anim->pFormatCtx->streams[anim->videoStream]->time_base);
av_q2d(anim->pFormatCtx->streams[anim->videoStream]
->time_base);
long long pos; long long pos;
long long st_time = anim->pFormatCtx long long st_time = anim->pFormatCtx->start_time;
->streams[anim->videoStream]->start_time;
int ret; int ret;
if (seek_by_bytes) { if (seek_by_bytes) {
@ -876,7 +881,7 @@ static ImBuf * ffmpeg_fetchibuf(struct anim * anim, int position) {
} }
if (st_time != AV_NOPTS_VALUE) { if (st_time != AV_NOPTS_VALUE) {
pos += st_time * AV_TIME_BASE * time_base; pos += st_time;
} }
} }
@ -891,9 +896,9 @@ static ImBuf * ffmpeg_fetchibuf(struct anim * anim, int position) {
} }
pts_to_search = (long long) pts_to_search = (long long)
(((double) position) / time_base / frame_rate); (((double) position) / pts_time_base / frame_rate);
if (st_time != AV_NOPTS_VALUE) { if (st_time != AV_NOPTS_VALUE) {
pts_to_search += st_time; pts_to_search += st_time / pts_time_base/ AV_TIME_BASE;
} }
pos_found = 0; pos_found = 0;