[Asterisk-video] MP4Play async Audio / Video

[Ramtin Amin]

hello
 
The way I solved this problem was by sending a H223SkewIndication message to the other terminal
Acutally, You will have to ask Sergio to add a H245 indication message of type h223SkewIndication and when playing the video with mp4play, he will have to see the difference of timing between Video and Audio and then send this value to the remote terminal so the lip sync would work...
 
 
 
2.3 Multipoint Lip Synchronization
In a multipoint VC, each terminal may transmit different
H223SkewIndication message for associated video and
audio channels in H.223 protocol. To enable lip
synchronization at receiving terminals, MCUs will
transmit accurate H223SkewIndication messages. MCUs
may accomplish this by adding delay to equalize the
audio/video skew for all transmitting terminals. When
switching between broadcasting terminals, H.223 may
transmit a new H223SkewIndication message reflecting the
audio/video skew of the current broadcaster.
 
-- 
Ramtin Amin
 



> From: thomas.frieling at viif.de> To: asterisk-video at lists.digium.com> Date: Mon, 24 Sep 2007 11:48:12 +0200> Subject: Re: [Asterisk-video] MP4Play async Audio / Video> > Hi Thomas Z!> > I think this problem is due to the bitrate restriction on 3G calls. The> audio stream is always sent immediately while the video stream has to> use what is left of the bandwidth. This is why videos become synchrous> again when the video bitrate is pretty low for a while in the video...> > Take a look at this discussion:> http://lists.digium.com/pipermail/asterisk-video/2007-September/001257.html> > One solution is to reencode every video with a low bitrate and use a> fixed bitrate encoder (ffmpeg is dynamic bitrate for example). I had the> impression though that this still doesn't always work, especially when> the UMTS connection is not too good...> > My idea is that we check each time before sending a keyframe if there is> already a new keyframe in the queue. If this is the case, we jump to the> most recent keyframe and just drop the data before that.> > What do you think about this? How hard to implement?> > Regards,> Thomas F> > > > Am Montag, den 24.09.2007, 11:15 +0200 schrieb Thomas Z.:> > Hello,> > > > We have the problem, that a converted mp4 file is asynchronous via 3g> > network.> > If we play the file on a pc, everything is synchron.> > We tried already to reduce the quality and framerate of the video. But> > nothing helps.> > > > Is it a problem with mp4play or with the video?> > > > What can we do to get the audio and video synchronized via 3g network?> > > > Thank you,> > best regards> > Thomas> > > > > > > > _______________________________________________> > --Bandwidth and Colocation Provided by http://www.api-digital.com--> > > > asterisk-video mailing list> > To UNSUBSCRIBE or update options visit:> > http://lists.digium.com/mailman/listinfo/asterisk-video> -- > www.ViiF.de - your Mobile Video Community> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~> > Thomas Frieling - IT Development> ViiF Mobile Video GmbH, Poststr. 21-22, 10178 Berlin > Cell: +49 (0) 173 63 62 62 3> > mailto:thomas at ViiF.de> > Sitz: Berlin, Amtgericht Berlin-Charlottenburg, HRB: 108350B> > Geschäftsführer: Daniel Höpfner, Steffen Brünn> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~> > _______________________________________________> --Bandwidth and Colocation Provided by http://www.api-digital.com--> > asterisk-video mailing list> To UNSUBSCRIBE or update options visit:> http://lists.digium.com/mailman/listinfo/asterisk-video
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