[MS-RTVPF]:
RTP Payload Format for RT Video Streams Extensions
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Revision Summary
Date / Revision History / Revision Class / Comments /04/04/2008 / 0.1 / Initial version
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1/1
[MS-RTVPF] — v20140721
RTP Payload Format for RT Video Streams Extensions
Copyright © 2014 Microsoft Corporation.
Release: July 31, 2014
Table of Contents
1 Introduction 6
1.1 Glossary 6
1.2 References 7
1.2.1 Normative References 7
1.2.2 Informative References 7
1.3 Overview 7
1.4 Relationship to Other Protocols 7
1.5 Prerequisites/Preconditions 7
1.6 Applicability Statement 8
1.7 Versioning and Capability Negotiation 8
1.8 Vendor-Extensible Fields 8
1.9 Standards Assignments 8
2 Messages 9
2.1 Transport 9
2.2 Message Syntax 9
2.2.1 RTP Header Usage 9
2.2.2 RTVideo Basic RTP Payload Format 10
2.2.3 RTVideo Extended RTP Payload Format 11
2.2.4 RTVideo Extended 2 RTP Payload Format 13
2.2.5 RTVideo FEC RTP Payload Format 15
3 Protocol Details 18
3.1 Sender Details 18
3.1.1 Abstract Data Model 18
3.1.2 Timers 18
3.1.3 Initialization 18
3.1.4 Higher-Layer Triggered Events 18
3.1.4.1 Send a RTVideo Frame 18
3.1.5 Message Processing Events and Sequencing Rules 18
3.1.5.1 Choice of RTP Payload Format 18
3.1.5.2 Fragmenting Video Frames 19
3.1.5.2.1 Maximum Video Fragment Size 19
3.1.5.2.2 Additional Requirement for FEC 19
3.1.5.3 Understanding the Sequence Header 19
3.1.5.4 Forward Error Correction (FEC) Algorithm 19
3.1.5.4.1 RTP Header Usage for FEC packets 20
3.1.5.4.2 FEC Metadata Packet Usage 20
3.1.5.5 SP-Frame and Cached Frame mechanisms 20
3.1.5.6 Other Requirements 21
3.1.6 Timer Events 21
3.1.7 Other Local Events 21
3.2 Receiver Details 21
3.2.1 Abstract Data Model 21
3.2.2 Timers 22
3.2.3 Initialization 22
3.2.4 Higher-Layer Triggered Events 22
3.2.4.1 Receive a Video Packet 22
3.2.4.2 Parsing RTVideo Packets 22
3.2.5 Message Processing Events and Sequencing Rules 22
3.2.6 Timer Events 23
3.2.7 Other Local Events 23
4 Protocol Examples 24
4.1 Basic RTP Payload Format Examples 24
4.1.1 I-Frame 24
4.1.1.1 First Packet 24
4.1.1.2 Second Packet 24
4.1.1.3 Last Packet 24
4.1.2 SP-Frame 24
4.1.2.1 First Packet 24
4.1.2.2 Second Packet 25
4.1.2.3 Last Packet 25
4.1.3 P-Frame or B-Frame 25
4.1.3.1 First Packet/LastPacket 25
4.2 Extended RTP Payload Format Examples 25
4.2.1 I-Frame 25
4.2.1.1 First Packet 25
4.2.1.2 Second Packet 26
4.2.1.3 Last Packet 26
4.2.2 P-Frame 26
4.2.2.1 First Packet/Last Packet 26
4.2.3 SP-Frame 26
4.2.3.1 First Packet 26
4.2.3.2 Second Packet 27
4.2.3.3 Last Packet 27
4.2.4 B-Frame 27
4.2.4.1 First Packet/Last Packet 27
4.3 FEC RTP Payload Format Examples 28
4.3.1 I-Frame 28
4.3.1.1 FEC Metadata Packet (FEC Version 0) 28
4.3.1.2 FEC Metadata Packet (FEC Version 1) 28
4.3.2 SP-Frame 28
4.3.2.1 FEC Metadata Packet 28
5 Security 30
5.1 Security Considerations for Implementers 30
5.2 Index of Security Parameters 30
6 Appendix A: Product Behavior 31
7 Change Tracking 33
8 Index 34
1/1
[MS-RTVPF] — v20140721
RTP Payload Format for RT Video Streams Extensions
Copyright © 2014 Microsoft Corporation.
Release: July 31, 2014
1 Introduction
The RTP Payload Format for RTVideo Streams Extensions [MS-RTVPF] protocol is a proprietary protocol describing the payload format for carrying real-time video streams in the payload of the Real-Time Transport Protocol (RTP). It is used to transmit and receive real-time video streams in two-party peer-to-peer calls and in multi-party conference calls.
Sections 1.8, 2, and 3 of this specification are normative and can contain the terms MAY, SHOULD, MUST, MUST NOT, and SHOULD NOT as defined in [RFC2119]. Sections 1.5 and 1.9 are also normative but does not contain those terms. All other sections and examples in this specification are informative.
1.1 Glossary
The following terms are defined in [MS-GLOS]:
big-endian
maximum transmission unit (MTU)
network byte order
The following terms are defined in [MS-OFCGLOS]:
B-frame
cached frame
endpoint
entry point header
forward error correction (FEC)
I-frame
P-frame
Real-Time Transport Protocol (RTP)
RTP packet
RTP payload
RTVC1
RTVideo
sequence header
Super P-frame (SP-frame)
The following terms are specific to this document:
GOP: A group of pictures that starts with one I-frame and ends with the next I-frame, excluding the next I-frame, as described in [SMPTE-VC-1].
RTVideo FEC metadata packet: A packet that is generated by using the forward error correction (FEC) algorithm to provide redundancy. It is packetized in the RTVideo FEC Real-Time Transport Protocol (RTP) payload format.
RTVideo frame: A video frame that is encoded by using an RTVC1 codec.
video data packet: A video data block that encapsulates a complete video frame or a fragment of a video frame. It contains the video payload header and the video payload.
MAY, SHOULD, MUST, SHOULD NOT, MUST NOT: These terms (in all caps) are used as described in [RFC2119]. All statements of optional behavior use either MAY, SHOULD, or SHOULD NOT.
1.2 References
References to Microsoft Open Specification documents do not include a publishing year because links are to the latest version of the documents, which are updated frequently. References to other documents include a publishing year when one is available.
1.2.1 Normative References
We conduct frequent surveys of the normative references to assure their continued availability. If you have any issue with finding a normative reference, please contact . We will assist you in finding the relevant information.
[MS-RTP] Microsoft Corporation, "Real-time Transport Protocol (RTP) Extensions".
[MS-SDPEXT] Microsoft Corporation, "Session Description Protocol (SDP) Version 2.0 Extensions".
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997, http://www.rfc-editor.org/rfc/rfc2119.txt
[SMPTE-VC-1] Society of Motion Picture and Television Engineers, "VC-1 Compressed Video Bitstream Format and Decoding Process", SMPTE 421M-2006, 2006, http://www.smpte.org/standards
1.2.2 Informative References
[MS-GLOS] Microsoft Corporation, "Windows Protocols Master Glossary".
[MS-OFCGLOS] Microsoft Corporation, "Microsoft Office Master Glossary".
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and Jacobson, V., "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, July 2003, http://www.ietf.org/rfc/rfc3550.txt
1.3 Overview
This protocol specifies a payload format to transport an RTVC1 bitstream using the Real-Time Transport Protocol (RTP).
This protocol accepts an RTVC1-encoded video frame. It fragments the video frame into one or more packets enumerated in a data packet list containing RTVideo. Each RTVideo video data packet contains an RTVideo payload header and a video payload. The RTVideo video data packet list optionally has one or more (up to 31) RTVideo FEC metadata packets appended to the end of the list. Each RTVideo FEC metadata packet contains an RTVideo forward error correction (FEC) payload header and FEC metadata.
1.4 Relationship to Other Protocols
This protocol carries the RTVC1 bitstream, described in [SMPTE-VC-1], as a payload, and in turn is carried as a payload in RTP, as described in [MS-RTP].
1.5 Prerequisites/Preconditions
This protocol specifies only the payload format for RTVideo video streams. This protocol requires the establishment of an RTP stream, a mechanism to obtain RTVideo video frames for it to packetize, and a mechanism to render RTVideo video frames that it has depacketized.
Higher layers are required to provide RTVideo frames with the following added information about each frame:
I-frame Flag: Specifies whether the frame is an I-frame.
SP-frame Flag: Specifies whether the frame is a Super P-frame (SP-frame).
cached frame Flag: Specifies whether the frame is a cached frame.
sequence header: This is required for each I-frame. It is not needed for other frame types.
Higher layers are required to provide video frames in referencing order. Frames being referenced are required to be provided earlier than frames referring to them.
Higher layers are also required to respect the following assumptions:
§ An I-frame does not have any reference frame.
§ I-frames and SP-frames are cached frames as well.
§ An SP-frame refers to the previous cached frame.
§ A P-frame refers to the previous P-frame, SP-frame, or I-frame.
§ A B-frame refers to the previous P-frame, SP-frame, or I-frame.
1.6 Applicability Statement
This protocol is only applicable for transporting video frames encoded using the RTVC1 codec.
1.7 Versioning and Capability Negotiation
This protocol has the following versioning constraints:
§ Supported Transports: This protocol uses RTP as its transport as discussed in section 2.1.
§ Protocol Versions: This protocol supports FEC Version 0 and FEC Version 1 as discussed in section 2.2.
The RTP Payload Format for RTVideo Streams Extensions protocol does not have any capability negotiation constraints.
1.8 Vendor-Extensible Fields
None.
1.9 Standards Assignments
None.
2 Messages
2.1 Transport
This protocol is a payload for the [MS-RTP] transport protocol and therefore relies on RTP for providing means to transport its payload over the network.
2.2 Message Syntax
This protocol defines four RTP payload formats:
RTVideo Basic RTP Payload Format:
The RTVideo Basic RTP Payload Format provides a basic scheme to packetize and transport RTVideo frames between a sender and receiver. It provides enough information to allow the receiver to reconstruct the video frames.