(RFC 5109 published December 2007, subtype last updated December 2007) Type name: video Subtype name: ulpfec Required parameters: rate: The RTP timestamp rate that is used to mark the time of transmission of the FEC packet in a separate stream. In cases in which it is sent as redundant data to another stream, the rate SHALL be the same as the primary encoding it is used to protect. When used in a separate stream, the rate SHALL be larger than 1000 Hz to provide sufficient resolution to RTCP operations. The selected rate MAY be any value above 1000 Hz, but is RECOMMENDED to match the rate of the media this stream protects. Optional parameters: onelevelonly: This specifies whether only one level of FEC protection is used. The permissible values are 0 and 1. If 1 is signaled, only one level of FEC protection SHALL be used in the stream. If 0 is signaled, more than one level of FEC protection MAY be used. If omitted, it has the default value of 0. Encoding considerations: This format is framed (see Section 4.8 in the template document [3]) and contains binary data. Security considerations: The same security considerations apply to these media type registrations as to the payloads for them, as detailed in RFC 5109. Interoperability considerations: none Published specification: RFC 5109 Applications that use this media type: Multimedia applications that seek to improve resiliency to loss by sending additional data with the media stream. Additional information: none Person & email address to contact for further information: Adam Li adamli&hyervision.com IETF Audio/Video Transport Working Group Intended usage: COMMON Restrictions on usage: This media type depends on RTP framing, and hence is only defined for transfer via RTP [1]. Transport within other framing protocols SHALL NOT be defined as this is a robustness mechanism for RTP. Author: Adam Li adamli&hyervision.com Change controller: IETF Audio/Video Transport Working Group delegated from the IESG.