IEC 61937-8:2006 pdf free download

IEC 61937-8:2006 pdf free download Digital Audio – Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 – Part 8: Non-linear PCM bitstreams according to the Windows Media Audio (WMA) Professional format
Scope
This part of lEC 61937 specifies the method for the digital audio interface specified inIEC 60958 to convey non-linear PCM bitstreams encoded in accordance with the WMAProfessional format.
2Normative references
The following referenced documents are indispensable for the application of this document.For dated references,only the edition cited applies. For undated references, the latest editionof the referenced document (including any amendments) applies.
IEC 60958(all parts),Digital audio interface
IEC 61937-1，Digital audio – Interface for non-linear PCM encoded audio bitstreams applyingEC 60958- Part 1: General
IEC 61937-2,Digital audio – Interface for non-linear PCM encoded audio bitstreams applyingEC 60958- Part 2: Burst-info
3Terms, definitions and abbreviations
For the purposes of this document,the following terms，definitions, abbreviations andpresentation convention apply.
3.1 Terms and definitions
3.1.1
latency
delay time of an external audio decoder to decode a WMA Professional data burst, defined asthe sum of two values of the receiving delay time and the decoding delay time
3.2Abbreviations
ATSC
Advanced Television Systems Committee
MPEG
The Moving Pictures Expert Group, a joint committee of lso and lEC
ITU-R
International Telecommunication Union,Radio communication Bureau
WMA
Windows Media Audio
3.3Presentation convention
F872h
Value’F872′ in hexadecimal format
4 Mapping of the audio bitstream on to IEC 61937
4.1 General
The coding of the bitstream and data-burst shall be in accordance with IEC 61 937-1 .
4.2 Windows Media Audio Professional burst-info
The 1 6-bit burst-info contains information about the data that will be found in the data-burst in accordance with Table 1 .
5 Format of WMA Professional data-burst
5.1 General
This clause specifies the audio data-burst for WMA Professional. Specific properties such as reference 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 the transmitter to schedule data-bursts as necessary to establish synchronization between picture and decoded audio.
5.2 Pause data-burst
Pause data-burst for WMA Professional Types I, II, III, and IV are given in Table 2.
5.3 Audio data-bursts
5.3.1 The data-burst for WMA Professional Type I WMA Professional Type I is primarily intended for use at sample rates above 48 kHz (for example, 88,2 kHz or 96 kHz). The IEC 60958 link should be operated at the sample rate of the decoded audio.
The WMA Professional bitstream consists of a sequence of WMA Professional frames. The data-type of a WMA Professional Type I data-burst is 1 2 h and the subtype is 0 h. A WMA Professional Type I frame represents 4 096 samples of each encoded audio channel (left, centre, etc.) transmitted in two sequential data-bursts. The data-burst is headed with a burst- preamble, followed by the burst-payload. The burst-payload of each pair of data-bursts of WMA Professional Type I data shall contain one complete WMA Professional frame. The length of the WMA Professional data-burst will depend on the encoded bit rate (which determines the WMA Professional frame length).