[Mp4-tech] Help on Delivery of MPEG-4 stream over IP networks

[Hans-Juergen Bardenhagen]

Hi Gaofeng,
on 19.02.04, 18:55 local time (received 20.02.04, 12:18 GMT+1) you wrote:
> Normally, how are these streams transmitted over Internet in real
> time for interactive communication? Are they transmitted over
> separate RTP channels? Or they are multiplexed in synchronization
> layer and then transmitted in a single stream over RTP?

The MPEG-4 Systems standard allows both methods, as far as I know.
> In current most implementations, with respect to streaming delivery
> over Internet, do they follow MPEG-4 system architecture standard to
> develop components such as DMIF, Flexmux, multiplexing SL packets,
> synchronization between streams, and DAI? If so, are there any open
> source? would you please tell me the links to these implemenations?

http://mpeg4ip.sourceforge.net/ and
http://sourceforge.net/projects/mpeg4ip/
This open source project started by Cisco does not use most of the  
Systems features, e.g. it can only send and receive one complete RTP  
stream of MPEG-4 content, not single tracks within a scene from  
different locations. But it might be used as a video conferencing  
application over IP, although the project admin does not recommend it  
due to the encoding delay if I remember correctly. You should probably  
test it yourself if it can be used for your purpose. The live-streaming  
tool in their package "mp4live" only exists in a Linux version, by the  
way.
On the player/client side there also exists GPAC/Osmo4 which is probably  
the most advanced MPEG-4 Systems open source project at the moment, but  
they do not offer a streaming/server solution yet.
http://gpac.sourceforge.net/
The open source VideoLAN project also provides a client and server for  
MPEG-4 content with VLC, but it does not support Systems features yet.
http://www.videolan.org/
And of course there is the IBM Toolkit for MPEG-4, but it's not open  
source, although free for testing purposes.
ZZee ya, Hans-Jürgen