BS EN 61937-10:2011 pdf free.Digital audio – Interfacefor non-linear PCM encodedaudio bitstreams applying IEC 60958 Non-linear PCM bitstreams accordingto the MPEG-4 Audio Lossless Coding (ALS)format.
BS EN 61937-10 This clause specifies the audio data-burst MPEG-4 ALS. Specific properties，such asreference points, repetition period, the method of filling stream gaps,and decoding latency,are specified for each data-type.
The decoding latency (or delay),indicated for the data-types，should be used by thetransmitter to schedule data-bursts, as necessary, to establish synchronisation between videoand decoded audio.
Figure 1 shows the detailed description of the MPEG-4 ALS data-burst. The stream of thedata-bursts for MPEG-4 ALS consists of sequences of MPEG-4 ALS bitstreams.The data-type of a MPEG-4 ALS data-burst is 23.The sub data-type is 0.The data-burst is headed witha burst-preamble，followed by the burst-payload,and stuffed with stuffing bits. The burst-payload of each data-burst of MPEG-4 ALS data shall contain an ALSSpecificConfig header,and one or more ALS random access units.Each data-burst constitutes a self-contained ALSbitstream，whose number of samples (per channel) is given in the field ‘samples’ of (thecorresponding)ALSSpecificConfig. The units of length-code (burst_length) shall be in 8-bytes.Note that if the actual data size of the data-burst is not a multiple of 8 bytes,1 to 7 stuffingbytes are included in the burst_length.
The number of samples for each encoded channel contained in the data-burst are indicated in theencoded ALS bitstream.The length of the MPEG-4 ALS data-burst depends on the encoded bit rate(which determines the MPEG-4 ALS frame length).For details, see Annex B.
The reference to the specification for the MPEG-4 ALS bitstream, representing the numberof samples of encoded audio per frame, may be found in ISO/IEC14496-3, subpart 11.
Terms, definitions, abbreviations and conventions For the purposes of this document, the following terms and definitions, abbreviations andpresentation conventions apply.
sub data-type:reference to the type of payload of the data-burst defined for use with the specified data-type.
latency delay time of an external audio decoder to decode a MPEG-4 ALS data-burst, defined as thesum of the receiving delay time and the decoding delay time.
length code:code indicating the length of the data-burst-payload in 8-byte units according to this standard.BS EN 61937-10 pdf download.