[Live-devel] .m4v / .mp3 Synchronization

[Ross Finlayson]

>I am prototyping a streaming application using an MPEG-1, Layer 3 
>(.mp3) audio file and an MPEG-4 video elementary stream (.m4v) file 
>as inputs.  I am doing this to simulate our actual encoder outputs 
>since they are not yet available.  I recorded these files from two 
>different physical sources on two different days.  When I wrap them 
>into an MPEG-2 transport stream, I experience synchronization issues.

This has nothing to do with RTP streaming.  When you stream a 
Transport Stream, it is done as a single RTP stream (*not* as 
separate audio and video streams).  All synchronization happens 
within the Transport Stream.

I suspect that you'll see the same synchronization problem if you 
just *play* your Transport Stream locally using a media player 
(rather than trying to stream it via RTP).  That is what you should 
test first.

Your synchronization problem occurred when you *created* 
(multiplexed) your Transport Stream from your audio and video inputs. 
If you used our software to create your Transport Stream (it wasn't 
really clear from your message whether or not you did), then you 
should make sure that you're setting correct timestamps on each frame 
of data that you feed into the multiplexor.
-- 

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/