ITU-T Recommendations

This amendment extends MPEG-2 systems with the capability to transport MPEG-4 streaming text, as specified in ISO/IEC 14496-17, and MPEG-4 lossless audio, as specified in ISO/IEC 14496-3. Carriage of streaming text and lossless audio in PES packets is defined and the stream-id and stream-type based signalling capabilities are extended. In the context of the STD model, requirements are defined for the carriage and the decoding of streaming text and lossless audio. For lossless audio, this includes parameters for buffer management, while the STD model is extended for streaming text. Furthermore, an MPEG-4 text descriptor is defined, carrying textConfig with basic information needed for the decoding of the associated text stream. This amendment also defines an MPEG-4 audio extension descriptor, which is an optional descriptor that can be carried next to an MPEG-4 audio descriptor. The MPEG-4 audio extension descriptor may carry the AudioSpecificConfig information, thereby creating the option for receivers to retrieve information about the associated audio stream without accessing the stream itself. In addition, in the case that the associated audio stream complies to more than one profile, the MPEG-4 audio extension descriptor can signal those profiles.