RTP Payload Format for Payload MetaInformation

1
RTP Payload Format for Payload Meta-Information
draft-serenyi-avt-rtp-meta-00.txt Denis
Serenyi QuickTime, Apple
2
What is it?

• Per-packet, payload independent information
• Accompanies an underlying payload
• Needed by caching proxies, reflectors

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Structure of the Payload
0 1 2
3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7
8 9 0 1 2 3 4 5 6 7 8 9 0 1 -----------
--------------------- C
field ID field len field
data -----------------
---------------
....
------------------------
-------- C field name
field len
------------------------
--------
field data
------------------------
--------
....
------------------------
-------- C field ID field len
field data
------------------------
--------
....
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Negotiation

• RTSP SETUP x-RTP-Meta-Info header
• Request x-RTP-Meta-Info tobibo
• Response x-RTP-Meta-Info to0bibo1
• SDP Description
• mother 5084 RTP/AVP 96
• artpmap96 x-RTP-Meta-Info/90000/to0bibo
• ax-embedded-rtpmapQT/90000

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Open Issues

• RTSP SETUP alters media description
• How to describe underlying payload in the SDP?
• IP-layer fragmentation

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More Open Issues

• Compressed / standard negotiation.
• RTP header of Meta-Info packet applies to the
  underlying payload
• Is additional compression necessary?