[FFmpeg-devel] Skip Frame in MJPEG video

Michael Niedermayer michaelni at gmx.at
Fri May 27 16:11:43 CEST 2011

On Fri, May 27, 2011 at 03:16:02PM +0200, christophe laferriere wrote:
> Le 27 mai 2011 à 15:08, Michael Niedermayer a écrit :
> > On Fri, May 27, 2011 at 10:21:36AM +0200, christophe laferriere wrote:
> >> I mean that I'm looking for a way to skip all bytes (in a FILE* in my case) from a same frame (for example in order to maintain a certain framerate.) so I was wondering how does the equivalent piece of code from ffmpeg look like.
> > 
> > the frame rate maintaince code is in ffmpeg.c in
> > if(video_sync_method){
> > 
> > one could say the:
> >    if (nb_frames <= 0)
> >        return;
> > 
> > is doing the skiping
> Ok. Thanks for pointing this out!
> > 
> > This does not work on "FILE *" level it works on frame level.
> > You need a demuxer first to get the frames out of a file and then you
> > can in case of intra only codecs skip frames.
> Ok so then I'd like to have a look at the demuxer code for mjpeg files. But don't bother, I'm gonna search by myself. I guess (and hope) it's in the libavcodec directory, in mjpeg* files.

demuxer is in libavformat
and which depends on how mjpeg is stored, it might be avidec.c
ffprobe will tell you more about what is used for your file

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

You can kill me, but you cannot change the truth.
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