[Ffmpeg-devel] Seeking with in an MPEGTS

Michael Niedermayer michaelni
Mon Jun 27 09:48:01 CEST 2005


On Tuesday 21 June 2005 15:42, M?ns Rullg?rd wrote:
> Andy Parkins said:
> > On Tuesday 2005 June 21 14:24, M?ns Rullg?rd wrote:
> >> > I've generated an MPEG transport stream containing an MPEG4 ES using
> >> > libavformat.  When playing back using ffplay, it plays back perfectly
> >> > until I perform a seek.  After that the stream breaks up for a bit,
> >> > then settles down but I start to get lots of error messages from
> >> > h263.c; for example.
> >>
> >> MPEG TS doesn't contain information about key frames, so when you seek
> >> you are likely to end up with some P/B frames before the next I frame. 
> >> Nothing to be worried about.  You could junk the decoder output until
> >> the next I frame comes around.  Look at AVFrame.key_frame.
> >
> > Thanks; but I don't think this is the case.  I'm happy with the messed up
> > picture, which fixes as soon as there is a key frame.  However, the
> > quoted error messages continue well after the next key frame has been
> > passed. Something about seeking is throwing off the decoder permanently.
> MPEG TS doesn't necessarily return complete frames, so after the seek you
> are probably getting the end of a frame.  If the decoder parses this as the
> start of a frame, I can imagine those errors occurring.  Apparently, this
> leaves the decoder in a permanent state of confusion.  Michael?

i need some sample with which i can reproduce this


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