RTP Payload Format Restrictions
draft-ietf-mmusic-rid-15
Network Working Group A. Roach (Editor)
Internet-Draft Mozilla
Updates: 4855 (if approved) May 15, 2018
Intended status: Standards Track
Expires: November 16, 2018
RTP Payload Format Restrictions
draft-ietf-mmusic-rid-15
Abstract
In this specification, we define a framework for specifying
restrictions on RTP streams in the Session Description Protocol.
This framework defines a new "rid" ("restriction identifier") SDP
attribute to unambiguously identify the RTP Streams within an RTP
Session and restrict the streams' payload format parameters in a
codec-agnostic way beyond what is provided with the regular Payload
Types.
This specification updates RFC4855 to give additional guidance on
choice of Format Parameter (fmtp) names, and on their relation to the
restrictions defined by this document.
Status of This Memo
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This Internet-Draft will expire on November 16, 2018.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
Roach (Editor) Expires November 16, 2018 [Page 1]
Internet-Draft RTP Restrictions May 2018
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Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Key Words for Requirements . . . . . . . . . . . . . . . . . 4
4. SDP "a=rid" Media Level Attribute . . . . . . . . . . . . . . 4
5. "a=rid" restrictions . . . . . . . . . . . . . . . . . . . . 6
6. SDP Offer/Answer Procedures . . . . . . . . . . . . . . . . . 8
6.1. Generating the Initial SDP Offer . . . . . . . . . . . . 8
6.2. Answerer processing the SDP Offer . . . . . . . . . . . . 9
6.2.1. "a=rid"-unaware Answerer . . . . . . . . . . . . . . 9
6.2.2. "a=rid"-aware Answerer . . . . . . . . . . . . . . . 9
6.3. Generating the SDP Answer . . . . . . . . . . . . . . . . 10
6.4. Offerer Processing of the SDP Answer . . . . . . . . . . 11
6.5. Modifying the Session . . . . . . . . . . . . . . . . . . 13
7. Use with Declarative SDP . . . . . . . . . . . . . . . . . . 13
8. Interaction with Other Techniques . . . . . . . . . . . . . . 13
8.1. Interaction with VP8 Format Parameters . . . . . . . . . 14
8.1.1. max-fr - Maximum Framerate . . . . . . . . . . . . . 14
8.1.2. max-fs - Maximum Framesize, in VP8 Macroblocks . . . 14
8.2. Interaction with H.264 Format Parameters . . . . . . . . 15
8.2.1. profile-level-id and max-recv-level - Negotiated Sub-
Profile . . . . . . . . . . . . . . . . . . . . . . . 16
8.2.2. max-br / MaxBR - Maximum Video Bitrate . . . . . . . 16
8.2.3. max-fs / MaxFS - Maximum Framesize, in H.264
Macroblocks . . . . . . . . . . . . . . . . . . . . . 16
8.2.4. max-mbps / MaxMBPS - Maximum Macroblock Processing
Rate . . . . . . . . . . . . . . . . . . . . . . . . 16
8.2.5. max-smbps - Maximum Decoded Picture Buffer . . . . . 17
8.3. Redundancy Formats and Payload Type Restrictions . . . . 17
9. Format Parameters for Future Payloads . . . . . . . . . . . . 18
10. Formal Grammar . . . . . . . . . . . . . . . . . . . . . . . 18
11. SDP Examples . . . . . . . . . . . . . . . . . . . . . . . . 20
11.1. Many Bundled Streams using Many Codecs . . . . . . . . . 20
11.2. Scalable Layers . . . . . . . . . . . . . . . . . . . . 22
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
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