[M4IF Technotes] Use Rtp to transport Mpeg4 video

[Bill May]

Hans-Juergen Bardenhagen wrote:
> On Thursday, 03.07.03, 09:14 (received 03.07.03, 06:49) Li wrote:
> 
> 
>>Now I'm trying to transport Mpeg4 video stream over RTP, and coming
>>against a problem. The RTP says that the configuration information,
>>such as Visual Object Sequence Header and other headers, should be
>>bond into a rtp packet. Then How to determine the time stamp of such
>>a rtp packet? The time stamp of the rtp packet consisting of a vop
>>can be easily determined by inspecting its vop-time-increment syntax.
> 
> 
> As far as I know, the elementary streams in a MP4 container must be  
> "hinted" for this, i.e. creating individual time stamp tracks that are  
> added to the the container. At least this is how the open source MPEG4IP  
> project handles RTP streaming e.g. with Apple's Darwin Streaming Server  
> (DSS). See http://sourceforge.net/projects/mpeg4ip/ for more, they also  
> have a web forum which you can search through and ask Bill May from  
> Cisco if you need further information.

Hinting is just done when you want to play back VOD from a streaming
server.
We do not usually stream the VOSH/VOL, instead those fields are in the
a=fmtp statement in the SDP describing the session.  If you must stream
them, they must be included at the beginning of the next packet
(RFC 3016, section 3.2, statement (1).  I believe that if you do not
include any more packet information, the timestamp is fairly irrelevant;
if you include the VOP, the timestamp should reflect that frame.
Bill