[Asterisk-video] MP4Play async Audio / Video

[Thomas Frieling]

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
> 
> 
> 
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