[linux-dvb] Re: Lipsync

[Johannes Stezenbach <js@convergence.de>]

Dennis Noordsij wrote:
> 
> I am having audio/video sync problems on specific channels, both live viewing 
> and playing back a recording. It only happens on channels MTV3 and SubTV 
> which are on the same mux, not on any other muxes. It does not happen all the 
> time, although certain programs are always problematic.
> 
> If I'd have to isolate a difference (all DVB-T muxes, all same settings apart 
> from frequency) it is that those channels sometimes have 48kHz audio whereas 
> the others seem to stick with 44.1kHz.
> 
> Using dvb-kernel under 2.4.22, both an older CVS (~ 10 days old) and a recent 
> one yesterday, same thing.  VDR 1.2.5. Primary card is a Siemens DVB-C 
> revision 1.5 without a signal (no ves1820 module loaded, no problems 
> whatsoever with the arm) and tuner card is a Hauppauge Nova-T ("new" model).

AV7110 based cards support PES playback only, and thus have to rely on the audio
and video PTS (presentation time stamps) only for lipsync. You'd have to
check if the PTS of audio and video are there, and are within certain
limits for the sync to work. If the stream is too badly muxed it will
play async. I don't know any tool to check this, maybe the Metzler Bros.
mpegtools can do it.


Johannes


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