RTP Payload Format for Bundled MPEG (RFC2343)
Original Publication Date: 1998-May-01
Included in the Prior Art Database: 2019-Feb-15
Internet Society Requests For Comment (RFCs)
M. Civanlar: AUTHOR [+2]
This document describes a payload type for bundled, MPEG-2 encoded video and audio data that may be used with RTP, version 2. This memo defines an Experimental Protocol for the Internet community. This memo does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested.
Network Working Group M. Civanlar Request for Comments: 2343 G. Cash Category: Experimental B. Haskell AT&T Labs-Research May 1998
RTP Payload Format for Bundled MPEG
Status of this Memo
This memo defines an Experimental Protocol for the Internet community. This memo does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (1998). All Rights Reserved.
This document describes a payload type for bundled, MPEG-2 encoded video and audio data that may be used with RTP, version 2. Bundling has some advantages for this payload type particularly when it is used for video-on-demand applications. This payload type may be used when its advantages are important enough to sacrifice the modularity of having separate audio and video streams.
This document describes a bundled packetization scheme for MPEG-2 encoded audio and video streams using the Real-time Transport Protocol (RTP), version 2 .
The MPEG-2 International standard consists of three layers: audio, video and systems . The audio and the video layers define the syntax and semantics of the corresponding "elementary streams." The systems layer supports synchronization and interleaving of multiple compressed streams, buffer initialization and management, and time identification. RFC 2250  describes packetization techniques to transport individual audio and video elementary streams as well as the transport stream, which is defined at the system layer, using the RTP.
Civanlar, et. al. Experimental [Page 1]
RFC 2343 RTP Payload Format for Bundled MPEG May 1998
The bundled packetization scheme is needed because it has several advantages over other schemes for some important applications including video-on-demand (VOD) where, audio and video are always used together. Its advantages over independent packetization of audio and video are:
1. Uses a single port per "program" (i.e. bundled A/V). This may increase the number of streams that can be served e.g., from a VOD server. Also, it eliminates the performance hit when two ports are used for the separate audio and video streams on the client side.
2. Provides implicit synchronization of audio and video. This is particularly convenient when the A/V data is stored in an interleaved format at the server.
3. Reduces the header overhead. Since using large packets increases the effects of losses and delay, audio only packets need to be smaller increasing the overhead. An A/V bundled format can provide about 1% overall overhead reduction. Considering the high bitrates used for MPEG-2 encoded material, e.g. 4 Mbps, the number of bits saved, e.g. 40 Kbps, may provide noticeable audio or video quality improvement.
4. May reduce overall receiver buffer size. Audio and video streams may experience different delays when transmitted separately. The receiver buffers need to be designed for the lon...