Information technology -- MPEG video technologies -- Part 3: Representation of auxiliary video and supplemental information

ISO/IEC 23002-3:2007 defines auxiliary video streams as data coded as video sequences and supplementing a primary video sequence. Depth maps and parallax maps are the first specified types of auxiliary video streams, relating to stereoscopic-view video content. In this context, ISO/IEC 23002-3:2007 specifies syntax and semantics for conveying information describing the interpretation of auxiliary video streams.

Syntax for such information is specified in ISO/IEC 23002-3:2007 as a stream of data referred to as a supplemental information (SI) message stream. Provisions for extensibility have been included, so that additional types of data can be defined in future extensions of the current SI message stream syntax by ISO/IEC.

An SI message stream can contain several concatenated SI messages, hence conveying various types of information. The auxiliary video SI (AVSI) is the only currently-defined type of SI (other than reserved SI message types that are reserved for future specification by ISO/IEC and are to be ignored by decoders if present). An AVSI message characterizes the interpretation of an auxiliary video sequence that accompanies a primary video sequence. For instance, an AV