[Live-devel] User Private Data Streams via RTSP?

[Ross Finlayson]

>The user private data streams are as described in ITU-T Rec 222.0, 
>Annex H, bullet item 3, "second possibility", "private data within 
>PES packets under the stream_type Table 2-34" as private_stream_1. 
>These are carried under their own PID as a separate elementary 
>stream in the multiplex.
>
>From your comments I gather that when Live555 transmits an MPEG2 
>Transport Stream you do not demux it and send the elementary streams 
>but rather send it as am RTP/AVP MP2T media type ala RFC 2250.  I 
>assume RTSP work with this media type?

Yes.


>While this would provide us with transparent transmission of our 
>private data ES, we anticipate running on a very noisy channel and 
>would like to have the advantages of having elementary streams on 
>separate RTP sessions to make error concealment simpler.  This would 
>involve demuxing the elementary streams and adding a media type and 
>support for "data" to get our private data stream across.

You would need to figure out which RTP payload format to use...


>I'd be curious as to your feelings about the need for this.  The 
>case for elementary stream transmission is made pretty well here:
>http://www.envivio.com/pdf/RTPvsTS-v4.pdf

Yes, although - depending on your particular environment (& packet 
loss characteristics, unicast or multicast etc.) - there are other 
options to consider as well (in particular, Forward Error Correction 
(FEC) on Transport Stream data over raw-UDP).
-- 

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