Type name: video

Subtype name: smpte291

Required parameters:

   Rate:
      RTP timestamp clock rate.

      When an ANC data RTP stream is to be associated with an RTP
      video stream, the RTP timestamp rates SHOULD be the same to
      ensure that ANC data packets can be associated with the
      appropriate frame or field.  Otherwise, a 90 kHz rate SHOULD be
      used.

      Note that techniques described in RFC 7273 [RFC7273] can
      provide a common reference clock for multiple RTP streams
      intended for synchronized presentation.

Optional parameters:

   DID_SDID:
      Data identification and secondary data identification words.

      The presence of the DID_SDID parameters signals that all ANC
      data packets of this stream are of a particular type or types,
      i.e., labeled with particular DIDs and SDIDs.  DID and SDID
      values of SMPTE-registered ANC data packet types can be found
      in the SMPTE Registry for Data Identification Word Assignments
      [SMPTE-RA].

      "Type 1" ANC data packets (which do not have SDIDs defined)
      SHALL be labeled with SDID=0x00.

      DID and SDID values can be registered with SMPTE as per SMPTE
      ST 291-1 [ST291].

      The absence of the DID_SDID parameter signals that
      determination of the DID and SDID of ANC data packets in the
      payload can only be achieved through direct inspection of the
      ANC data packet fields.

      The ABNF description of the DID_SDID parameter is described in
      Section 4.

   VPID_Code:
      This integer parameter specifies the Video Payload ID (VPID)
      code of the source interface of ANC data packets using the
      value from byte 1 of the VPID as defined in SMPTE ST 352
      [ST352].  The integer SHALL be made with bit 7 of VPID byte 1
      being the most significant bit and bit 0 of VPID byte 1 being
      the least significant bit.  For example, 132 refers to SMPTE ST
      292-1, 720-line video payloads on a 1.5 Gbps (nominal) serial
      digital interface.

Encoding considerations: This media type is framed and binary; see
Section 4.8 of RFC 6838 [RFC6838].

Security considerations: See Section 7 of RFC 8331.

Interoperability considerations: Data items in smpte291 can be very
diverse.  Receivers might only be capable of interpreting a subset of
the possible data items.  Some implementations might care about the
location of the ANC data packets in the SDI raster, but other
implementations might not care.

Published specification: RFC 8331

Applications that use this media type: Devices that stream real-time
professional video, especially those that interoperate with legacy
serial digital interfaces (SDI).

Additional Information:

   Deprecated alias names for this type: N/A

   Magic number(s): N/A

   File extension(s): N/A

   Macintosh file type code(s): N/A

Person & email address to contact for further information:

   T. Edwards <thomas.edwards&fox.com>
   IETF Payload Working Group <payload&ietf.org>

Intended usage: COMMON

Restrictions on usage: This media type depends on RTP framing and
hence is only defined for transfer via RTP RFC 3550 [RFC3550].
Transport within other framing protocols is not defined at this time.

Author: T.  Edwards <thomas.edwards&fox.com>

Change controller: The IETF PAYLOAD Working Group, or other party as
designated by the IESG.