SMPTE ST 352 – Payload Identification for Serial Digital Interfaces

This standard defines the specification of a 4-byte payload identifier that describes aspects of the payload carried on the SMPTE Serial Digital Interface (SDI) such as: the digital interface standard; picture rate; sampling structure; aspect ratio; colorimetry; bit depth and channel or link assignment. Other application specific aspects of the payload such as audio channel usage, may optionally be described in application specific documents that reference SMPTE ST 352.

The payload identifier is applicable to all serial digital interfaces and all payloads that produce a directly viewable image on a display device. Furthermore, the viewable image must be a recognizable representation of the source image content.

The payload identifier is mandatory for some reference standards and optional in other reference standards. Refer to the applicable reference standards for further information on mandatory or optional usage of the SMPTE ST 352 payload identifier.

The standard defines how the payload identifier is placed into a 10-bit ancillary data packet according to SMPTE ST 291-1.

It also specifies the repetition rate of the ancillary data packet, and provides the preferred horizontal and vertical location for the placement of the packet in different digital interfaces.

The standard defines values for some of the bit fields of each byte of the 4-byte payload identifier, although the values for other bit fields can have custom definitions.

The standard also defines the Payload Identification Code assignment process and associated on-line register for Byte 1 Values. See Annex A for details on how to register new values.

Annex B and Annex C define the assigned Payload Identification codes and byte 2, 3 and 4 values for legacy systems.

Annex D shows the mapping of the payload identifier from the ancillary data packet structure of SMPTE ST 291-1 to the K-L-V data structure of SMPTE ST 336 as a fixed-length data pack.