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1、BRITISH STANDARD BS EN 61937:2001 IEC 61937:2000 Digital audio Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 The European Standard EN 61937:2000 has the status of a British Standard ICS 33.160.30; 35.040 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LA
2、W Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 03:50:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 61937:2001 This British Standard, having been prepared under the direction of the Electrotechnical Sector Committee, was published under the authority of the Standards Committee and com
3、es into effect on 15 June 2001 BSI 06-2001 ISBN 0 580 37292 8 National foreword This British Standard is the official English language version of EN 61937:2000. It is identical with IEC 61937:2000. The UK participation in its preparation was entrusted by Technical Committee EPL/100, Audio, video and
4、 multimedia systems and equipment, to Subcommittee EPL/100/3, Equipment and systems in the field of audio, video and audiovisual engineering, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. From 1 January 1997, al
5、l IEC publications have the number 60000 added to the old number. For instance, IEC 27-1 has been renumbered as IEC 60027-1. For a period of time during the change over from one numbering system to the other, publications may contain identifiers from both systems. Cross-references Attention is drawn
6、 to the fact that CEN and CENELEC Standards normally include an annex which lists normative references to international publications with their corresponding European publications. The British Standards which implement these international or European publications may be found in the BSI Standards Ca
7、talogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for thei
8、r correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interes
9、ts informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 29, and a back cover. The BSI copyright date displayed in this document indicates when the
10、document was last issued. Amendments issued since publication Amd. No. DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 03:50:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARDEN 61937 NORME EUROPENNE EUROPISCHE NORMNovember 2000 CENELEC European Committee for Electro
11、technical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2000 CENELEC -All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No.
12、 EN 61937:2000 E ICS 33.160.01 English version Digital audio - Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 (IEC 61937:2000) Audionumrique - Interface pour les flux de bits audio codage MIC non linaire conformment la CEI 60958 (CEI 61937:2000) Digitalton - Schnittstelle f
13、r nicht-PCM-codierte Audio-Bitstrme unter Verwendung von IEC 60958 (IEC 61937:2000) This European Standard was approved by CENELEC on 2000-08-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status
14、of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A
15、version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
16、 Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 03:50:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Foreword The text of document 100C
17、/260/FDIS, future edition 1 of IEC 61937, prepared by SC 100C, Audio, video and multimedia subsystems and equipment, of IEC TC 100, Audio, video and multimedia systems and equipment, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61937 on 2000-08-01. The following d
18、ates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement(dop) 2001-05-01 latest date by which the national standards conflicting with the EN have to be withdrawn(dow) 2003-08-01 Annexes designated “normati
19、ve“ are part of the body of the standard. In this standard, annexes A and ZA are normative. Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 61937:2000 was approved by CENELEC as a European Standard without any modification. _ Page 2 EN 61937:2000 L
20、icensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 03:50:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ? BSI 05-2001 CONTENTS Page Clause 1Scope 5 2Normative references. 5 3Definitions and abbreviations 5 3.1Definitions 5 3.2Abbreviations 7 3.3Presentation convention 7 4General 8 5Interface forma
21、t . 8 6Mapping of the audio bitstream on to IEC 60958. 8 6.1Coding of the bitstream. 8 6.1.1Bit map of bitstream 9 6.1.2IEC 60958 validity flag10 6.1.3IEC 60958 channel status bit 1.10 6.1.4Symbol frequency.10 6.1.5Format of data-bursts.11 6.1.6Burst-preamble 11 6.1.7Burst-info.12 6.1.8Length-code.1
22、3 6.2Burst-payload.14 6.3Stuffing14 6.3.1Stuffing within an IEC 60958 subframe .14 6.3.2Stuffing between data-bursts14 6.3.3Burst spacing.14 7Format of data-bursts15 7.1Pause data-burst .16 7.2Audio data-bursts.19 7.2.1AC-3 19 7.2.2MPEG-1 layer-1 .21 7.2.3MPEG-1 layer-2 or layer-3, or MPEG-2 without
23、 extension .21 7.2.4MPEG-2 with extension 22 7.2.5MPEG-2, layer-1 low sampling frequency24 7.2.6MPEG-2 layer-2 or 3 low sampling frequency25 7.3Null data-burst .25 Annex A (normative) Channel status when the IEC 60958 interface is used in consumer applications.27 Annex ZA (normative) Normative refer
24、ences to international publications with their corresponding European publications 29 Bibliography 28 Page 3 EN 61937:2000 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 03:50:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ? BSI 05-2001 Page Figure 1 IEC 60958 interface format 9 Figure 2 Data
25、-burst format11 Figure 3 Length of the burst-payload Pd14 Figure 4 Burst spacing14 Figure 5 Flow chart of transmission of a bitstream 15 Figure 6 Bridging gaps in between data-bursts with three pause data-bursts .16 Figure 7 Data-burst format of the data-type pause 17 Figure 8 AC-3 data-burst, with
26、reference point R.19 Figure 9 Delay of AC-3 decoding 20 Figure 10 MPEG-1 layer-1 data-burst21 Figure 11 Data-burst with MPEG-1 layer-2 or layer-3, or MPEG-2 without extension 21 Figure 12 Latency of MPEG decoding .22 Figure 13 Format of MPEG base frame and MPEG extension frame23 Figure 14 MPEG-2 wit
27、h extension data-burst 23 Figure 15 MPEG-2 layer-1 low sampling frequency data-burst.24 Figure 16 MPEG-2 layer-2 or 3 low sampling frequency data-burst25 Figure 17 Null data-burst 25 Table 1 Bit allocation of IEC 60958 frame 9 Table 2 Bit allocation of data-burst in IEC 60958 subframes10 Table 3 Bur
28、st-preamble words 11 Table 4 Bit map of burst-preambles 12 Table 5 Fields of burst-info .12 Table 6 Repetition period of pause data-bursts .18 Table 7 Values of data-type-dependent info of the pause data-burst18 Table 8 Burst-payload of pause data-burst18 Table 9 Data-type-dependent information when
29、 data-type = 1 .19 Table 10 Data-type-dependent information for data-types 5 and 6 .23 Table 11 Fields of a null data-burst.26 Table A.1 Allocation of channel status bits 27 Page 4 EN 61937:2000 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 03:50:54 GMT+00:00 2006, Uncontrolled Copy, (c) BS
30、I ? BSI 05-2001 DIGITAL AUDIO INTERFACE FOR NON-LINEAR PCM ENCODED AUDIO BITSTREAMS APPLYING IEC 60958 1 Scope This International Standard applies to the digital audio interface using the IEC 60958 series for the conveying of non-linear PCM encoded audio bitstreams. It describes a way in which this
31、digital interface can be used in consumer applications. The professional mode (AES/EBU) is not considered within the scope of this standard. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International
32、Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicat
33、ed below. For undated references, the latest edition of the normative document referred to applies. Members of IEC and ISO maintain registers of currently valid International Standards. IEC 60958-1:1999, Digital audio interface Part 1: General IEC 60958-3:1999, Digital audio interface Part 3: Consum
34、er applications ISO/IEC 11172-3:1993, Information technology Coding of moving pictures and associated audio for digital storage media at up to about 1,5 Mbit/s Part 3: Audio ISO/IEC 13818-3:1995, Information technology Generic coding of moving pictures and associated audio information Part 3: Audio
35、ITU-R Recommendation BS.1196:1995, Audio coding for digital terrestrial television 3 Definitions and abbreviations 3.1 Definitions For the purpose of this standard, the following definitions apply. 3.1.1 audio data-burst data-burst with an encoded audio frame as burst-payload 3.1.2 audio frame fixed
36、 number of audio samples. The 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 Page 5 EN 61937:2000 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 03:50:54 GMT+00:00 2006, Uncontrolled Copy
37、, (c) BSI ? BSI 05-2001 3.1.3 audio gap period in the sequence of baseband audio samples where valid samples of audio are not available 3.1.4 base frame MPEG-1 compatible part of the MPEG-2 encoded audio frame (see ISO/IEC 13818-3) 3.1.5 bitstream non-linear PCM encoded audio source represented in a
38、 sequence of bits. 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 data-burst 3.1.8 burst-preamble header for the data-burst, co
39、ntaining 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. Each encoded audio frame is the encoded representation of a fixed
40、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 frame 3.1.11 extension frame one encoded frame out of the MPEG exten
41、sion bitstream (see ISO/IEC 13818-3) 3.1.12 idle state of the interface when IEC 60958 is not used to convey any sequence of data-bursts or PCM data. The channel status data is still active (bit b1 is set to “1“ when further non-linear PCM encoded audio is anticipated, see annex A) 3.1.13 IEC 60958
42、frame sequence of two successive and associated IEC 60958 subframes Page 6 EN 61937:2000 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 03:50:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ? BSI 05-2001 3.1.14 length-code indication of the length of the data-burst-payload in bits 3.1.15 repet
43、ition 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 3.1.16 sampling frequency sampling frequency of the encoded PCM audio samples (i.e. before encoding and after decoding) 3.1.17 sampling peri
44、od time period related to the sampling frequency of the PCM audio samples, represented in the encoded bitstream 3.1.18 symbol frequency frequency of the bits on IEC 60958 3.1.19 stuffing occupying the unused data capacity of the interface 3.1.20 stuffing sub-frame occupying the unused data capacity
45、in IEC 60958 subframes 3.1.21 IEC 60958 sub-frame defined in IEC 60958 to convey a 16-bit to 24-bit data word 3.1.22 stream gap period within the encoded audio bitstream without any audio frame; discontinuity in the bitstream. Typically, a stream gap will occur between encoded audio frames 3.1.23 sy
46、mbol representation of one bit of IEC 60958 3.2 Abbreviations ATSCAdvanced Television Systems Committee IECInternational Electrotechnical Commission ISO/IEC MPEGMoving Pictures Expert Group ITU-RInternational Telecommunication Union, Radiocommunication 3.3 Presentation convention F872hValue “F872“ i
47、n hexadecimal format Page 7 EN 61937:2000 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 13 03:50:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ? BSI 05-2001 4 General The format of the IEC 60958 interface consists of a sequence of IEC 60958 subframes. Each IEC 60958 subframe is normally used t
48、o 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. Each data-burst consists of a 64-bit burst-preamble, followed by the burst-payload. The burst-preamble cons
49、ists 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 the repetition period for the data-bursts which make up the bitstream (see clause 7). The 16 bits of a data-burst are placed in time-slots 12 to 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 60