[FFmpeg-devel] [PATCH] mpegtsenc: Force writing PCR-only packet to PCR stream if the current stream is not the PCR stream

[Tomas Härdin]

On Thu, 2010-10-07 at 13:29 +0200, Tomas H?rdin wrote:
> On Wed, 2010-10-06 at 15:10 -0700, Baptiste Coudurier wrote:
> > On 10/06/2010 04:33 AM, Tomas H?rdin wrote:
> > > ...
> > >
> > > When writing non-video streams PCR still needs to be written
> > > periodically, but PCR may only be written for streams whose PID matches
> > > a service's PCR PID (typically the first video stream). The patch uses a
> > > simple solution for this: write a PCR-only packet with the video
> > > stream's PID, similarly to how such packets are written when padding for
> > > CBR mode. This is of course a bit wasteful when muxing VBR, but it is
> > > more correct AFAICT.
> > 
> > I agree, although the perfect solution would be write PCR based on 
> > timing. Specifications says that delta between PCRs shall be <= 0.1s
> > 
> > > ...
> > >
> > > A better solution would of course be to interleave the PES packets that
> > > make up the last few packets of each stream of each service, and make
> > > sure PCR is written for all services when required. At the moment I am
> > > more concerned with the muxer outputting a compliant bitstream though,
> > > rather than being the most efficient implementation.
> > 
> > I agree with that.
> 
> Hopefully I'll be given time later to improve the muxer. I have some
> ideas how this could be done without being too complicated.
> 
> > > [...]
> >  >
> > > +
> > > +        if(write_pcr&&  ts_st->pid != ts_st->service->pcr_pid) {
> > > +            /* write a pcr-only packet to the pcr stream since pcr needs to be
> > > +             * written but the current stream is not the pcr stream
> > > +             * FIXME: this is slightly wasteful in VBR mode */
> > 
> > Please no new FIXME, you can check wether you are in VBR mode or not.
> 
> Shouldn't PCR be written either way, even if doing VBR? Perhaps it
> should say NOTE instead of FIXME, or nothing at all. Attached patch
> simply removes it.
> 
> /Tomas

ping?

/Tomas
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