SMPTE ST 272:2004

Abtract:

(1.1) This standard defines the mapping of AES digital audio data, AES auxiliary data, and associated control information into the ancillary data space of serial digital video conforming to ANSI/SMPTE 259M or SMPTE 344M. The audio data and auxiliary data are derived from AES3, hereafter referred to as AES audio. The AES audio data may contain linear PCM audio or non-PCM data formatted according to SMPTE 337M. (1.2) Audio sampled at 48 kHz and clock locked (synchronous) to video is the preferred implementation for intrastudio applications. As an option, this standard supports AES audio at synchronous or asynchronous sampling rates from 32 kHz to 48 kHz. (1.3) The minimum, or default, operation of this standard supports 20 bits of audio data as defined in clause 3.5. As an option, this standard supports 24-bit audio or four bits of AES auxiliary data as defined in clause 3.10. (1.4) This standard provides a minimum of two audio channels and a maximum of 16 audio channels based on available ancillary data space in a given format (four channels maximum for composite digital). Audio channels are transmitted in pairs combined, where appropriate, into groups of four. Each group is identified by a unique ancillary data ID. (1.5) Several modes of operation are defined and letter suffixes are applied to the nomenclature for this standard to facilitate convenient identification of interoperation between equipment with various capabilities. The default form of operation is 48-kHz synchronous audio sampling carrying 20 bits of AES audio data and defined in a manner to ensure reception by all equipment conforming to this standard.