[Live-devel] Mpeg2 ES and audio PCM stream Synchronization with Live555

[Guy Bonneau]

Thanks Ross for the feedback,

I understand that you are quite busy. Keep the good
work. That library is great work.

Regards
Guy

> -----Original Message-----
> From: live-devel-bounces at ns.live555.com 
> [mailto:live-devel-bounces at ns.live555.com] On Behalf Of Ross Finlayson
> Sent: Tuesday, February 12, 2008 8:56 PM
> To: LIVE555 Streaming Media - development & use
> Subject: Re: [Live-devel] Mpeg2 ES and audio PCM stream 
> Synchronization with Live555
> 
> I haven't had time to wade through this in detail, but it 
> seems that you've run into the same problem that I had when I 
> was developing the "wis-streamer" application 
> <http://www.live555.com/wis-streamer/>. 
> Namely, if your streaming server is fed audio and video data 
> as two streams of *unstructured data* - rather than two 
> streams of discrete frames - then it is difficult to ensure 
> that the resulting audio and video frames - when parsed from 
> each stream - will get accurate presentation times (and it 
> will be difficult to ensure that they remain accurate over 
> time).  (You get proper a/v synchronization at the client end 
> if and only if the server-generated presentation times were accurate.)
> 
> As I found with "wis-streamer", the solution is to change 
> your application so that it is fed streams of *discrete* 
> frames, each having its own presentation timestamp that is 
> generated directly, when it the frame is produced (e.g., by a 
> hardware encoder).  Then you don't have to parse the streams 
> to extract (possibly inaccurate) presentation times.  I.e., 
> instead of using "MPEG1or2VideoStreamFramer", use 
> "MPEG1or2VideoStreamDiscreteFramer".
> 
> So, I suggest that you revew the "wis-streamer" source code 
> for hints that may help your application.
> 
> (This will be my last posting on this subject.)
> -- 
> 
> Ross Finlayson
> Live Networks, Inc.
> http://www.live555.com/
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