ÖNORM EN ISO 9887

This part of ISO/IEC 11172 specifies the system layer of the coding. It was developed principally to support the combination of the video and audio coding methods defined in ISO/IEC 11172-2 and ISO/IEC 11172-3. The system layer supports five basic functions: a) the synchronization of multiple compressed streams on playback, b) the interleaving of multiple compressed streams into a single stream, c) the initialization of buffering for playback start up, d) continuous buffer management, and e) time identification. An ISO/IEC 11172 multiplexed bit stream is constructed in two layers: the outermost layer is the system layer, and the innermost is the compression layer. The system layer provides the functions necessary for using one or more compressed data streams in a system. The video and audio parts of this specification define the compression coding layer for audio and video data. Coding of other types of data is not defined by the specification, but is supported by the system layer provided that the other types of data adhere to the constraints defined in clause 2.4.