(RFC4788 published January 2007, updated February 2008 per RFC 5188) Type name: audio Subtype name: EVRCB0 Required parameters: None Optional parameters: These parameters apply to RTP transfer only. recvmode: A mode of the EVRC-B codec. A decoder can use this attribute to inform an encoder of its preference to operate in a specified mode. Possible values are 0..7 (see the encoder operating point column in Table 2-6 of 3GPP2 C.S0014-B). sendmode: A mode of the EVRC-B codec. An encoder can use this to signal its current mode of operation. Possible values are 0..7 (see the encoder operating point column in Table 2-6 of 3GPP2 C.S0014-B). silencesupp: See Section 6.1 of RFC 4788 for a definition. If this parameter is not present, the default value 1 MUST be assumed. dtxmax: see Section 6.1 of RFC 4788. dtxmin: see Section 6.1 of RFC 4788. hangover: see Section 6.1 of RFC 4788. Encoding considerations: This media type is framed binary data (see RFC 4288, Section 4.8) and is defined for transfer of EVRC-B encoded data via RTP using the header-free packet format specified in RFC 3558. Security considerations: See Section 9 of RFC 4788. Interoperability considerations: None Published specification: The EVRC-B vocoder is specified in 3GPP2 C.S0014-B. The transfer method with the header-free packet format via RTP is specified in RFC 3558, RFC 4788, and RFC 5188. Applications that use this media type: It is expected that many VoIP applications (as well as mobile applications) will use this type. Additional information: None Person & email address to contact for further information: Harikishan Desineni Intended usage: COMMON Restrictions on usage: When this media type is used in the context of transfer over RTP, the RTP payload format specified in Section 4.2 of RFC 3558 SHALL be used. This media type depends on RTP framing and hence is only defined for transfer via RTP [6]; the RTP payload format specified in Section 4.2 of RFC 3558 SHALL be used. This media type SHALL NOT be used for storage or file transfer using the file format defined in Section 5 of RFC 4788; instead, audio/EVRCB SHALL be used. Author: Qiaobing Xie / Harikishan Desineni Change controller: IETF Audio/Video Transport working group delegated from the IESG.