(RFC 5993 published October 2010)

Media Type Definition

The media type for the GSM-HR codec is allocated from the IETF tree,
since GSM-HR is a well-known speech codec.  This media type
registration covers real-time transfer via RTP.

Note: Reception of any unspecified parameter MUST be ignored by the
receiver to ensure that additional parameters can be added in the
future.

Type name: audio

Subtype name: GSM-HR-08

Required parameters: none

Optional parameters:

   max-red: The maximum duration in milliseconds that elapses between
   the primary (first) transmission of a frame and any redundant
   transmission that the sender will use.  This parameter allows a
   receiver to have a bounded delay when redundancy is used.  Allowed
   values are integers between 0 (no redundancy will be used) and
   65535.  If the parameter is omitted, no limitation on the use of
   redundancy is present.

   ptime: See [RFC8826].

   maxptime: See [RFC8826].

Encoding considerations:

   This media type is framed and binary; see Section 4.8 of RFC 4288
   [RFC4288].

Security considerations:

   See Section 10 of RFC 5993.

Interoperability considerations:

   The media subtype name contains "-08" to avoid potential conflict
   with any earlier drafts of GSM-HR RTP payload types that aren't
   bit-compatible.

Published specifications:

   RFC 5993, 3GPP TS 46.002

Applications that use this media type:

   Real-time audio applications like voice over IP and
   teleconference.

Additional information: none

Person & email address to contact for further information:

   Ingemar Johansson <ingemar.s.johansson&ericsson.com>

Intended usage: COMMON

Restrictions on usage:

   This media type depends on RTP framing, and hence is only defined
   for transfer via RTP [RFC3550].  Transport within other framing
   protocols is not defined at this time.

Authors:

   Xiaodong Duan <duanxiaodong&chinamobile.com>

   Shuaiyu Wang <wangshuaiyu&chinamobile.com>

   Magnus Westerlund <magnus.westerlund&ericsson.com>

   Ingemar Johansson <ingemar.s.johansson&ericsson.com>

   Karl Hellwig <karl.hellwig&ericsson.com>

Change controller:

   IETF Audio/Video Transport working group, delegated from the IESG.