1、 IEC 61937-1Edition 2.0 2007-01INTERNATIONAL STANDARD Digital audio Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 Part 1: General IEC61937-1:2007(E) THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2007 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specif
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9、for non-linear PCM encoded audio bitstreams applying IEC 60958 Part 1: General INTERNATIONAL ELECTROTECHNICAL COMMISSION SICS 33.160.30 PRICE CODEISBN 2-8318-8956-1 2 61937-1 IEC:2007(E) CONTENTS FOREWORD.4 1 Scope.6 2 Normative references .6 3 Terms, definitions, abbreviations and presentation .6 3
10、.1 Definitions .6 3.2 Abbreviations 8 3.3 Presentation convention 8 4 General description 8 5 Interface format 9 6 Mapping of the audio bitstream on to IEC 60958 9 6.1 Coding of the bitstream .9 6.2 Burst-payload14 6.3 Stuffing .15 7 Format of data-bursts .15 7.1 Pause data-burst.16 7.2 Audio data-b
11、ursts 19 7.3 Null data-burst.19 Annex A (normative) Channel status when IEC 60958 is used in consumer applications 20 Bibliography21 Figure 1 IEC 60958 interface format 9 Figure 2 Data-burst format.11 Figure 3 Burst-preamble 11 Figure 4 Burst-preamble with extended preamble 13 Figure 5 Length of the
12、 burst-payload specified by Pd.14 Figure 6 Burst spacing .15 Figure 7 Flow chart of transmission of a bitstream .16 Figure 8 Bridging gaps in-between data-bursts with three pause data-bursts .17 Figure 9 Data-burst format of the data-type pause .18 Figure 10 Null data-burst .19 Table 1 Bit allocatio
13、n of the IEC 60958 frame 9 Table 2 Bit allocation of data-burst in IEC 60958 subframes 10 Table 3 Burst-preamble words .12 Table 4 Bit map of burst-preambles .12 Table 5 Fields of burst-info 12 Table 6 Burst-preamble words .13 Table 7 Fields of Pe (extended data-type)13 61937-1 IEC:2007(E) 3 Table 8
14、 Fields of Pf13 Table 9 Values of data-type-dependent info of the pause data-burst 18 Table 10 Burst-payload of pause data-burst.19 Table 11 Fields of a null data-burst19 Table A.1 Allocation of the channel status bits .20 4 61937-1 IEC:2007(E) INTERNATIONAL ELECTROTECHNICAL COMMISSION _ DIGITAL AUD
15、IO INTERFACE FOR NON-LINEAR PCM ENCODED AUDIO BITSTREAMS APPLYING IEC 60958 Part 1: General FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC
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18、he IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearl
19、y as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees. 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that
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22、re to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an IEC Publication. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents
23、 including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or
24、 reliance upon, this IEC Publication or any other IEC Publications. 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of
25、the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61937-1 has been prepared by technical area 4: Digital system interfaces and protocols, of IEC technical committee 100
26、: Audio, video and multimedia systems and equipment. This second edition of IEC 61937-1 cancels and replaces the first edition published in 2000. This edition contains the following significant technical changes with respect to the previous edition. a) The data-type field in Pc is expanded from bit
27、0-4 to bit 0-6. b) A new additional definition of Pd is specified. c) The numbers of times for symbol frequency are changed to refer to each part of IEC 61937. d) The requirement for burst spacing is changed. 61937-1 IEC:2007(E) 5 The text of this standard is based on the following documents: FDIS R
28、eport on voting 100/1101/CDV 100/1192/RVC Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. The list of all the parts of IEC 61937, u
29、nder the general title Digital audio Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 can be found on the IEC website. The committee has decided that the contents of this publication will remain unchanged until the maintenance result date indicated on the IEC web site under “
30、http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed; withdrawn; replaced by a revised edition, or amended. A bilingual version of this publication may be issued at a later date. 6 61937-1 IEC:2007(E) DIGITAL AUDIO INTERFACE FOR NO
31、N-LINEAR PCM ENCODED AUDIO BITSTREAMS APPLYING IEC 60958 Part 1: General 1 Scope This part of IEC 61937 applies to the digital audio interface using the IEC 60958 series for the conveying of non-linear PCM encoded audio bitstreams. It describes the way in which this digital interface can be used in
32、consumer applications. The professional mode (AES/EBU) is not considered within the scope of this standard. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references,
33、the latest edition of the referenced document (including any amendments) applies. IEC 60958 (all parts), Digital audio interface IEC 61937 (all parts), Digital audio Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 3 Terms, definitions, abbreviations and presentation For the
34、purposes of this document, the following terms, definitions, abbreviations and presentation convention apply. 3.1 Definitions 3.1.1 audio data-burst data-burst with an encoded audio frame as burst-payload 3.1.2 audio data-word 16-bit data word 3.1.3 audio frame fixed number of audio samples NOTE The
35、 number of samples in an audio frame is dependent on the particular encoding system which is used to encode the audio frame into the encoded audio frame. 3.1.4 audio gap period in the sequence of baseband audio samples where valid samples of audio are not available 61937-1 IEC:2007(E) 7 3.1.5 bitstr
36、eam non-linear PCM encoded audio source, represented in a sequence of bits NOTE In this interface the bitstream consists of a sequence of data-bursts. 3.1.6 data-burst packet of data, including the burst-preamble, to be transmitted across the interface 3.1.7 burst-payload information content of the
37、data-burst 3.1.8 burst-preamble header for the data-burst, containing synchronization, and information about the data contained in the burst-payload 3.1.9 data-type reference to the type of payload of the data-bursts 3.1.10 encoded audio frame minimum decodable unit of an encoded data sequence NOTE
38、Each encoded audio frame is the encoded representation of a fixed number of audio samples (for each original audio channel). The number of samples which are encoded into an encoded audio frame depends on the particular encoding system which is used to encode the audio frame into the encoded audio fr
39、ame. 3.1.11 idle state in which the interface is not used to convey any sequence of data-bursts or PCM data NOTE The channel status data is still active (bit b1 is set to 1 when further non-linear PCM encoded audio is anticipated; see Figure 7). 3.1.12 length-code code indicating the length of the d
40、ata-burst-payload in bits or bytes 3.1.13 repetition period period between the reference point of the current data-burst and the reference point of the immediately following data-burst of the same data-type 3.1.14 sampling frequency sampling frequency of the encoded PCM audio samples (i.e. before en
41、coding and after decoding) 3.1.15 sampling period time period related to the sampling frequency of the PCM audio samples, represented in the encoded bitstream 3.1.16 stuffing occupying the unused data capacity of the interface 8 61937-1 IEC:2007(E) 3.1.17 stuffing subframe occupying the unused data
42、capacity in 16-bit audio data words 3.1.18 stream gap period within the encoded audio bitstream without any audio frame; a discontinuity in the bitstream NOTE Typically, a stream gap will occur between encoded audio frames. 3.2 Abbreviations 3.2.1 MPEG Moving Pictures Expert Group, a joint committee
43、 of ISO and IEC 3.2.2 SMPTE The Society of Motion Picture and Television Engineers 3.2.3 ETSI European Telecommunication Standards Institute 3.2.4 ATSC Advanced Television Standards Committee 3.3 Presentation convention F872h Value F872 in hexadecimal format 4 General description The format of the I
44、EC 60958 interface consists of a sequence of IEC 60958 subframes. Each IEC 60958 subframe is normally used to carry one linear PCM sample but may also be used to convey data. The non-linear PCM encoded audio bitstreams to be transported over this interface are formed into a sequence of data-bursts.
45、Each data-burst consists of a 64-bit burst-preamble, followed by the burst-payload. The burst-preamble consists of a sync-word, information about the burst-payload and a bitstream number. The interface may convey one or more bitstreams. Each type of bitstream may impose a particular requirement for
46、the repetition period for the data-bursts that make up the bitstream (see Clause 7). The 16 bits of a data-burst are placed in time-slots 12-27 of an IEC 60958 subframe. Both odd and even IEC 60958 subframes (ch1, ch2) are simultaneously used to carry 32 bits of data. This allows IEC 60958, in the c
47、onsumer mode, to convey either two-channel linear PCM audio, or a set of non-linear PCM encoded bitstreams (alternating data words), but not both simultaneously. 61937-1 IEC:2007(E) 9 5 Interface format The interface format as defined in IEC 60958-1 and IEC 60958-3 is used. 6 Mapping of the audio bi
48、tstream on to IEC 60958 6.1 Coding of the bitstream The non-linear PCM encoded audio bitstream is transferred using the basic 16-bit data area of the IEC 60958 subframes, i.e. in time-slots 12 to 27. Because the non-linear PCM encoded audio bitstream to be transported is at a lower data rate than th
49、at supported by the IEC 60958 interface, the audio bitstream is broken into a sequence of discrete data-bursts, and stuffing between the data-bursts is necessary (see 6.3). Each data-burst contains data of an encoded audio frame that is the encoded representation of a fixed number of audio samples per PCM audio channel. The number of samples to be encoded into an encoded audio frame depends on the particular encoding system. It is possible for t
