RTP Audio Payload Formats

RTP Payload Format for Enhanced Variable Rate Codecs (EVRC) and Selectable Mode Vocoders (SMV)
A. Li
RFC 3558
July 2003
This document describes the RTP payload format for Enhanced Variable Rate Codec (EVRC) Speech and Selectable Mode Vocoder (SMV) Speech. Two sub-formats are specified for different application scenarios. A bundled/interleaved format is included to reduce the effect of packet loss on speech quality and amortize the overhead of the RTP header over more than one speech frame. A non-bundled format is also supported for conversational applications.
Real-Time Transport Protocol (RTP) Payload Format and File Storage Format for the Adaptive Multi-Rate (AMR) and Adaptive Multi-Rate Wideband (AMR-WB) Audio Codecs
J. Sjoberg, M. Westerlund, A. Lakaniemi, and Q. Xie
RFC 3267
June 2002.
This document specifies a real-time transport protocol (RTP) payload format to be used for Adaptive Multi-Rate (AMR) and Adaptive Multi-Rate Wideband (AMR-WB) encoded speech signals. The payload format is designed to be able to interoperate with existing AMR and AMR-WB transport formats on non-IP networks. In addition, a file format is specified for transport of AMR and AMR-WB speech data in storage mode applications such as email. Two separate MIME type registrations are included, one for AMR and one for AMR-WB, specifying use of both the RTP payload format and the storage format.
RTP Payload Format for ITU-T Recommendation G.722.1
RFC 3047
P. Luthi.
January 2001.
International Telecommunication Union (ITU-T) Recommendation G.722.1 is a wide-band audio codec, which operates at one of two selectable bit rates, 24kbit/s or 32kbit/s. This document describes the payload format for including G.722.1 generated bit streams within an RTP packet. Also included here are the necessary details for the use of G.722.1 with MIME and SDP. This document is a product of the Audio/Video Transport Working Group of the IETF.
RTP Payloads for Telephone Signal Events
RFC 2833
Henning Schulzrinne, Scott Petrack.
May 2000

Implementation notes:

RTP Payload Format for European Telecommunications Standards Institute (ETSI) European Standard ES 201 108 Distributed Speech Recognition Encoding
RFC 3557
Q. Xie, ed.
July 2003.
This document specifies an RTP payload format for encapsulating European Telecommunications Standards Institute (ETSI) European Standard (ES) 201 108 front-end signal processing feature streams for distributed speech recognition (DSR) systems.
RTP Payload Format for AC-3 Streams
L. Flaks
August 2002.
This document describes an RTP payload format for transporting AC-3 encoded audio data. AC-3 is a high quality multichannel audio coding system fully described in [2] by the Advanced Television Standards Committee (ATSC). The RTP payload format presented in this document provides mechanisms for interleaving redundant data, which can increase packet loss resilience. An intelligent method for fragmenting AC-3 frames that exceed the maximum transfer unit (MTU) is also described.
RTP Payload for Comfort Noise
RFC 3389
R. Zopf
September 2002
This document describes a Real-time Transport Protocol (RTP) payload format for transporting comfort noise (CN). The CN payload type is primarily for use with audio codecs that do not support comfort noise as part of the codec itself such as ITU-T Recommendations G.711, G.726, G.727, G.728, and G.722.

"Vendors fielding products which use payload type 13 as comfort noise, with the single octet payload, are in conformance with the spec as it currently stands. The spec may change in future to include a multi-octet comfort noise format, so vendors using the existing format should be prepared to ignore any additional octets. It is our intention that draft-ietf-avt-rtp-cn-?? will become the new standard for payload type 13. The draft is intended to be an extension of the existing single-octet comfort noise format - one of the main areas we are soliciting feedback is whether this modification to the format will cause problems to existing implementations (if so, we may have to modify our plans)."(Colin Perkins, 07/13/00)

A More Loss-Tolerant RTP Payload Format for MP3 Audio
RFC 3119 R. Finlayson
June 2001
This document describes a RTP (Real-Time Protocol) payload format for transporting MPEG (Moving Picture Experts Group) 1 or 2, layer III audio (commonly known as "MP3"). This format is an alternative to that described in RFC 2250, and performs better if there is packet loss.
RTP Payload Format for Vorbis Encoded Audio
RTP Payload Format for 12-bit DAT Audio and 20- and 24-bit Linear Sampled Audio
RFC 3190
K. Kobayashi, A. Ogawa, S. Casner, C. Bormann
January 2002
This document specifies a packetization scheme for encapsulating 12-bit nonlinear, 20-bit linear, and 24-bit linear audio data streams using the Real-time Transport Protocol (RTP). This document also specifies the format of a Session Description Protocol (SDP) parameter to indicate when audio data is preemphasized before sampling. The parameter may be used with other audio payload formats, in particular L16 (16-bit linear).
RTP Payload Format for DV (IEC 61834) Video
RFC 3189
K. Kobayashi, A. Ogawa, S. Casner, C. Bormann
January 2002
This document specifies the packetization scheme for encapsulating the compressed digital video data streams commonly known as "DV" into a payload format for the Real-Time Transport Protocol (RTP).

Last updated by Henning Schulzrinne