1、BRITISH STANDARD BS EN 61937-4:2003 Incorporating Corrigendum No. 1 Digital audio Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 Part 4: Non-linear PCM bitstreams according to the MPEG audio format The European Standard EN 61937-4:2003 has the status of a British Standard I
2、CS 33.160.30 BS EN 61937-4:2003 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2003 BSI 29 July 2004 ISBN 0 580 42336 0 National foreword This British Standard is the official English language version of EN 61937-4:2003. It is identi
3、cal with IEC 61937-4:2003. Together with BS EN 61937-1, -2 and -3, it supersedes BS EN 61937:2001 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee EPL/100, Audio, video and multimedia systems and equipment, which has the responsibility to: A list of or
4、ganizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Corr
5、espondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not
6、 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 interests informed; monitor related international and European developmen
7、ts 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 13 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd.
8、No. Date Comments 15271 Corrigendum No. 1 29 July 2004 Correction to supersession detail in national forewordEUROPEAN STANDARD EN 61937-4 NORME EUROPENNE EUROPISCHE NORM June 2003 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisc
9、hes Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61937-4:2003 E ICS 33.160.30 English version Digital audio - Interface for no
10、n-linear PCM encoded audio bitstreams applying IEC 60958 Part 4: Non-linear PCM bitstreams according to the MPEG audio format (IEC 61937-4:2003) Audionumrique - Interface pour les flux de bits audio codage MIC non linaire conformment la CEI 60958 Partie 4 : Flux de bits PCM non-linaire selon le form
11、at audio MPEG (CEI 61937-4:2003) Digitalton - Schnittstelle fr nichtlinear-PCM-codierte Audio-Bitstrme unter Verwendung von IEC 60958 Teil 4: Nichtlineare PCM-Bitstrme nach den MPEG-Ton-Formaten (IEC 61937-4:2003) This European Standard was approved by CENELEC on 2003-06-01. CENELEC members are boun
12、d to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status 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 Ce
13、ntral Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A 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
14、status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and U
15、nited Kingdom. Foreword The text of document 100/647/FDIS, future edition 1 of IEC 61937-4, prepared by 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 61937-4 on 2003-06-01. The following dates were fixe
16、d: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2004-03-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2006-06-01 Annexes designated “normative“ are part
17、 of the body of the standard. In this standard, annex ZA is normative. Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 61937-4:2003 was approved by CENELEC as a European Standard without any modification. _ Page2 EN619374:2003169-734 IEC:2003(E) 3
18、CONTENTS 1 Scope.4 2 Normative references.4 3 Terms and definitions .4 3.1 Definitions.4 3.2 Abbreviations4 3.3 Presentation convention5 4 Mapping of the audio bitstream on to IEC 61937 5 5 Format of MPEG audio data-burst 5 5.1 General.5 5.2 Pause data-burst.5 5.3 Audio data-types.6 5.3.1 MPEG-1 lay
19、er-1.6 5.3.2 MPEG-1 layer-2 or -3, or MPEG-2 without extension .6 5.3.3 MPEG-2 with extension .7 5.3.4 MPEG-2 layer-1 low sampling frequency .9 5.3.5 MPEG-2 layer-2 Low sampling frequency 10 5.3.6 MPEG-2 layer-3 low sampling frequency .10 Annex ZA (normative) Normative references to international pu
20、blications with their corresponding European publications .12 Bibliography13 Figure 1 MPEG-1 layer-1 data-burst.6 Figure 2 Data-burst with MPEG-1 layer 2 or 3 or MPEG-2 without extension7 Figure 3 Latency of MPEG-1 layer 2 or 3 or MPEG-2 without extension .7 Figure 4 Format of MPEG-base-frame and MP
21、EG-extension-frame8 Figure 5 MPEG 2 with extension data-burst .8 Figure 6 Latency of MPEG-2 with extension.9 Figure 7 MPEG-2 layer-1 low sampling frequency data-burst .9 Figure 8 MPEG-2 layer-2 low sampling frequency data-burst .10 Figure 9 MPEG-2 layer-3 low sampling frequency data-burst .11 Table
22、1 Fields of burst-info 5 Table 2 Repetition period of pause data-bursts 6 Table 3 Data-type-dependent info for data-types 5 and 6.8 Page3 EN619374:2003 4 169-734 IE:C002(3)E DIGITAL AUDIO INTERFACE FOR NON-LINEAR PCM ENCODED AUDIO BITSTREAMS APPLYING IEC 60958 Part 4: Non-linear PCM bitstreams accor
23、ding to the MPEG audio formats 1 Scope This part of IEC 61937 specifies the method for the digital audio interface specified in IEC 60958 to convey non-linear PCM bitstreams encoded in accordance with the MPEG audio. 2 Normative references The following referenced documents are indispensable for the
24、 application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60958 (all parts), Digital audio interface IEC 61937-1, Digital audio Interface for non-linear PCM encode
25、d audio bitstreams applying IEC 60958 Part 1: General 3 Terms and definitions For the purposes of this document, the following definitions, abbreviations and presentation convention apply. 3.1 Definitions 3.1.1 latency delay time of an external audio decoder to decode an AC-3 data-burst, defined as
26、the sum of two values of the receiving delay time and the decoding delay time 3.2 Abbreviations 3.2.1 ATSC Advanced Television Systems Committee 3.2.2 MPEG Moving Pictures Expert Group, a joint committee of ISO and IEC 3.2.3 ITU-R International Telecommunication Union, Radio Communication Bureau Pag
27、e4 EN619374:2003169-734 IEC:2003(E) 5 3.3 Presentation convention F872h Value F872 in hexadecimal format 4 Mapping of the audio bitstream on to IEC 61937 The coding of the bitstream and data-burst is in accordance with IEC 61937-1. The 16-bit burst-info contains information about the data that will
28、be found in the data-burst (see Table 1). Table 1 Fields of burst-info Bits of Pc Value Contents Reference point R Repetition period of data-burst in IEC 60958 frames 0 4 Data-type 0 3 According to IEC 61937 4 MPEG-1 layer-1 data Bit 0 of Pa 384 5 MPEG-1 layer-2 or -3 data, or MPEG-2 without extensi
29、on Bit 0 of Pa 1 152 6 MPEG-2 data with extension Bit 0 of Pa 1 152 7 MPEG-2 AAC Bit 0 of Pa 1 024 8 MPEG-2 layer-1 low sampling frequency Bit 0 of Pa 768 9 MPEG-2 layer-2 low sampling frequency Bit 0 of Pa 2 304 10 MPEG-2 layer-3 low sampling frequency Bit 0 of Pa 1 152 10 31 According to IEC 61937
30、 5 15 According to IEC 61937 5 Format of MPEG audio data-burst 5.1 General This clause specifies the audio data-burst of MPEG audio. Specific properties such as reference points, repetition period, method of filling stream gaps and decoding latency are specified. The decoding latency (or delay), ind
31、icated 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-bursts for MPEG audio are given in Table 2. Page5 EN619374:2003 6 169-734 IE:C002(3)E Table 2 Repetition p
32、eriod of pause data-bursts Repetition period of pause data-burst Data-type of audio data-burst Mandatory Recommended MPEG-1 layer-1 data 32 IEC 60958 frames MPEG-1 layer-2 or -3 data, or MPEG-2 without extension 32 IEC 60958 frames MPEG-2 data with extension 32 IEC 60958 frames MPEG-2 layer-1 low sa
33、mpling frequency 64 IEC 60958 frames MPEG-2 layer-2 low sampling frequency 64 IEC 60958 frames MPEG-2 layer-3 low sampling frequency 64 IEC 60958 frames 5.3 Audio data-types 5.3.1 MPEG-1 layer-1 An MPEG-1 layer-1 MPEG-frame represents 384 samples of each encoded channel and can be transferred using
34、data-type 04h. The data-burst is headed with a burst-preamble, followed by the burst-payload. MPEG-1 layer-1 frame Bit 0 of Pa Repetition period of the burst Pa Pd Pc Pb Bit 0 of Pa Stuffing MPEG-1 layer-1 burst_payload Pa Pd Pc Pb IEC 1300/03Figure 1 MPEG-1 Layer-1 data-burst In the case where paus
35、e data-bursts are used to fill stream gaps in the MPEG-1 layer-1 bit- stream as described in IEC 61937-1, it is recommended that the pause data-bursts be transmitted with a repetition period of 32 IEC 60958 frames. The total gap length shall be a multiple of 32 IEC 60958 frames. When a stream gap in
36、 an MPEG bitstream is filled by a sequence of pause data-bursts, the Pa of the initial pause data-burst should be located at the 16-bit data word located 384 IEC 60958 frames following the Pa of the previous MPEG data-burst. The sequence(s) of pause data-bursts that fill the stream gap shall continu
37、e from this point up to the Pa of the first MPEG data-burst which follows the stream gap. The gap-length parameter contained in the pause data-burst may be used to specify the number of decoded PCM samples that are missing (due to the gap). The latency of an audio decoder to decode an MPEG-1 layer-1
38、 data-burst is not defined. 5.3.2 MPEG-1 layer-2 or -3, or MPEG-2 without extension The burst-payload of data type MPEG-1 layer-2 or -3 MPEG-2 without extension represents 1 152 samples of each encoded channel and can be transferred using data-type 05h. The data-burst is headed with a burst-preamble
39、, followed by the burst-payload. Page6 EN619374:2003169-734 IEC:2003(E) 7 Pa Pd Pc Pb MPEG-1 layer-2 or -3 or MPEG-2 without extension burst_payload MPEG-1 layer-2 or -3 or MPEG-2 without extension frame Repetition period of the burst Bit 0 of Pa Bit 0 of Pa Stuffing Pa Pd Pc Pb IEC 1301/03Figure 2
40、Data-burst with MPEG-1 layer-2 or -3 or MPEG-2 without extension NOTE An MPEG-2 layer-1 super-frame contains 3 MPEG-1 layer-1 base-frames and the MPEG-extension-frame. The MPEG layer-1 super-frame contains 3 384 = 1 152 samples per channel (see ISO/IEC 13818-3). The data-type-dependent info for MPEG
41、-1 layer-2 or -3 data or MPEG-2 without extension is given in Table 3. In the case where pause data-bursts are used to fill stream gaps in the MPEG-1 layer-2 or -3 data or MPEG-2 without extension bitstream as described in IEC 61937-1, it is recommended that the pause data-bursts be transmitted with
42、 a repetition period of 32 IEC 60958 frames. The total gap length shall be a multiple of 96 IEC 60958 frames. When a stream gap in an MPEG bitstream is filled by a sequence of pause data-bursts, the Pa of the initial pause data-burst should be located at the 16-bit data word located 1 152 IEC 60958
43、frames following the Pa of the previous MPEG data-burst. The sequence(s) of pause data-bursts that fill the stream gap shall continue from this point up to the Pa of the first MPEG data-burst which follows the stream gap. The gap-length parameter contained in the pause data-burst may be used to spec
44、ify the number of decoded PCM samples that are missing (due to the gap). Pa Pd Pc Pb MPEG-1 layer-2 or -3 or MPEG-2 without extension burst_payload MPEG-1 layer-2 or -3 or MPEG-2 without extension frame Repetition period of the burst Bit 0 of Pa Bit 0 of Pa Pa Pd Pc Pb Time to receive data-burst, wi
45、th maximum length Latency of MPEG-1 layer-2 or -3 or MPEG-2 without extension Decoding delay Stuffing IEC 1302/03Figure 3 Latency of MPEG-1 layer-2 or -3 or MPEG-2 without extension The latency of an audio decoder to decode a MPEG-1 layer-2 or -3 or MPEG-2 without extension data-burst is defined as
46、the time to receive the whole data-burst with maximum length (16,75 ms for fs = 48 kHz), plus the decoding delay, which is the time to output the first linear PCM sample (Figure 3, 4,15 ms for fs = 48 kHz). The latency is defined as a delay of 20,9 ms for fs = 48 kHz, 22,75 ms for fs = 44,1 kHz, and
47、 31,35 ms for fs = 32 kHz. 5.3.3 MPEG-2 with extension An MPEG-2 frame represents 1 152 samples of each encoded channel. The data type is 06h. The data-burst is headed with a burst-preamble, followed by the burst-payload. Page7 EN619374:2003 8 169-734 IE:C002(3)E MPEG-1 header MPEG-1 audio MC audio
48、Ancillary data Anc data Ext. header MPEG-2 burst_payload MPEG-2 base frame MPEG-2 extension frame MPEG-1 side info MC header MC side info I MC side info II MPEG-1 compatible MPEG-2 multi-channel IEC 1303/03Figure 4 Format of MPEG-base-frame and MPEG-extension-frame Bit 0 of Pa MPEG-2 burst_payload M
49、PEG-2 base frame, with extension frame Repetition period of burst Pa Pd Pc Pb Bit 0 of Pa Stuffing Pa Pd Pc Pb IEC 1304/03Figure 5 MPEG 2 with extension data-burst NOTE An MPEG-2 layer-1 MPEG-super-frame contains 3 layer-1 base frames and the extension frame. The layer- 1 MPEG-super-frame contains 3 384 = 1 152 samples per channel (see ISO/IEC 13818-3). T
