1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationDigital audio Interface for non-linear PCM encoded audio bitstreams applying IEC 60958Part 10: Non-linear PCM bitstreams according to the MPEG-4 Audio Lossless Coding (ALS) forma
2、tBS EN 61937-10:2011Incorporating corrigendum July 2011National forewordThis British Standard is the UK implementation of EN 61937-10:2011. It supersedes BS IEC 61937-10:2011, which is withdrawn.The UK participation in its preparation was entrusted to Technical CommitteeEPL/100, Audio, video and mul
3、timedia systems and equipment.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. BSI 2011ISBN 978 0 580 76292 5 I
4、CS 33.160.30; 35.240.99 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 August 2011.Amendments/Corrigendum issued since publicationDate Text affectedBRITISH S
5、TANDARDBS EN 61937-10:201131 July 2011 Renumbers BS IEC 61937-10:2011 as BS EN 61937-10: 2011EUROPEAN STANDARD EN 61937-10 NORME EUROPENNE EUROPISCHE NORM June 2011 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr
6、Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61937-10:2011 E ICS 33.160.30; 35.240.99 English version Digital audio - Interface for non-linea
7、r PCM encoded audio bitstreams applying IEC 60958 - Part 10: Non-linear PCM bitstreams according to the MPEG-4 Audio Lossless Coding (ALS) format (IEC 61937-10:2011) Audionumrique - Interface pour les flux de bits audio codage MIC non linaire conformment la CEI 60958 - Partie 10: Flux de bits codage
8、 MIC non-linaire selon le format MPEG-4 Audio sans perte (Audio Lossless Coding - ALS) (CEI 61937-10:2011) Digitalton - Schnittstelle fr nichtlinear-PCM-codierte Audio-Bitstrme unter Verwendung von IEC 60958 - Teil 10: Nichtlineare PCM-Bitstrme entsprechend dem Format MPEG-4-ALS (verlustfreie Audiod
9、atenkompression) (IEC 61937-10:2011) This European Standard was approved by CENELEC on 2011-05-25. CENELEC members are bound 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.
10、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 version in any other language made by translati
11、on 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, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estoni
12、a, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 61937-10:2011EN 61937-10:2011 - 2 - Foreword The text of docum
13、ent 100/1733/CDV, future edition 1 of IEC 61937-10, prepared by technical area 4, Digital system interfaces and protocols, 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 61937-10 on 2011-05-25. Attent
14、ion is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent rights. The following dates were fixed: latest date by which the EN has to be implemented at national l
15、evel by publication of an identical national standard or by endorsement (dop) 2012-02-25 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2014-05-25 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 61937
16、-10:2011 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following note has to be added for the standard indicated: IEC 60958-3 NOTE Harmonized as EN 60958-3. _ BS EN 61937-10:2011- 3 - EN 61937-10:2011 Annex ZA (normative) Norm
17、ative references to international publications with their corresponding European publications 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 edition of the referenced
18、document (including any amendments) applies. NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD YearIEC 60958 Series Digital audio interface EN 60958 Series IEC 61937 Series Digital audio - In
19、terface for non-linear PCM encoded audio bitstreams applying IEC 60958 EN 61937 Series IEC 61937-1 - Digital audio - Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 - Part 1: General EN 61937-1 - IEC 61937-2 - Digital audio - Interface for non-linear PCM encoded audio bitstr
20、eams applying IEC 60958 - Part 2: Burst-info EN 61937-2 - ISO/IEC 14496-3 + A2 2009 2010 Information technology - Coding of audio-visual objects - Part 3: Audio - - - - BS EN 61937-10:2011 2 EN 61937-10:2011 CONTENTS 1 Scope . 5 2 Normative references . 5 3 Terms, definitions, abbreviations and conv
21、entions 5 3.1 Terms and definitions 5 3.2 Abbreviations 6 3.3 Presentation convention 6 4 Mapping of the audio bitstream onto IEC 61937 . 6 4.1 General . 6 4.2 MPEG-4 ALS burst-info . 6 5 Format of MPEG-4 ALS data-bursts 7 5.1 General . 7 5.2 Audio data-bursts 7 5.2.1 Data-burst for MPEG-4 ALS . 7 5
22、.2.2 Latency of MPEG-4 ALS decoding . 9 Annex A (informative) Effect of repetition period of data-burst and IEC 60958 frame rate on frame period for the MPEG-4 ALS bitstreams 11 Annex B (normative) Burst payload format for MPEG-4 ALS 12 Annex C (normative) Values for ALSSpecificConfig in the MPEG-4
23、ALS burst payload format . 13 Bibliography 15 Figure 1 MPEG-4 ALS data-burst . 8 Figure 2 Latency of MPEG-4 ALS decoding . 9 Figure 3 The MPEG-4 ALS burst-payload. 9 Figure B.1 MPEG-4 ALS burst-payload 12 Table 1 Fields of burst-info (data-type=23, sub-data-type=0) . 7 Table 2 Sample rate and number
24、 of channels of MPEG-4 ALS encoded audio, multiplier, and IEC 60958 frame rate . 9 Table A.1 MPEG-4 ALS payload and frame repetition: some examples 11 Table C.1 Recommended values for the ALSSpecificConfig in the MPEG-4 ALS burst-payload 13 BS EN 61937-10:2011EN 61937-10:2011 5 DIGITAL AUDIO INTERFA
25、CE FOR NON-LINEAR PCM ENCODED AUDIO BITSTREAMS APPLYING IEC 60958 Part 10: Non-linear PCM bitstreams according to the MPEG-4 audio lossless coding (ALS) format 1 Scope This part of IEC 61937 specifies the method for IEC 60958 to convey non-linear PCM bitstreams encoded in accordance with the MPEG-4
26、audio lossless coding (ALS) format. 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, the latest edition of the referenced document (including any amendments)
27、 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 IEC 61937-1, Digital audio Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 Part 1: General IEC 61937-2, Digi
28、tal audio Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 Part 2: Burst-Info ISO/IEC 14496-3:2009, Information technology Coding of audio-visual objects Part 3: Audio Amendment 2:2010, ALS Simple Profile and Transport of SAOC 3 Terms, definitions, abbreviations and conventio
29、ns For the purposes of this document, the following terms and definitions, abbreviations and presentation conventions apply. 3.1 Terms and definitions 3.1.1 sub data-type reference to the type of payload of the data-burst defined for use with the specified data-type 3.1.2 latency delay time of an ex
30、ternal audio decoder to decode a MPEG-4 ALS data-burst, defined as the sum of the receiving delay time and the decoding delay time 3.1.2 length code code indicating the length of the data-burst-payload in 8-byte units according to this standard BS EN 61937-10:2011 6 EN 61937-10:2011 3.1.4 als_id ALS
31、 identifier in ALSSpecificConfig 3.1.5 samp_freq sampling frequency of the audio samples contained in the MPEG-4 ALS burst payload 3.1.6 samples number of audio samples per channel contained in the MPEG-4 ALS burst payload NOTE In contrast to the ALS specification, each data-burst provides its own A
32、LSSpecificConfig. Thus the samples value refers to the total number of samples (per channel) of that data-burst. 3.1.7 channels number of channels-1, channels, contained in the MPEG-4 ALS burst payload 3.1.8 resolution bit depth of the audio samples contained in the MPEG-4 ALS burst payload 3.1.9 au
33、x_size size of the auxiliary data field in bytes for MPEG-4 ALS 3.1.10 aux_data auxiliary data contained in the MPEG-4 ALS burst payload NOTE Not required for decoding audio samples. 3.2 Abbreviations ALS Audio Lossless Coding PCM Pulse-Code Modulation 3.3 Presentation convention 012Value “01” in bi
34、nary format 4 Mapping of the audio bitstream onto IEC 61937 4.1 General The coding of the bitstream and data-burst is in accordance with the IEC 61937 series of standards. 4.2 MPEG-4 ALS burst-info The 16-bit burst-info contains information about the data that will be found in the data-burst in acco
35、rdance with Table 1. BS EN 61937-10:2011EN 61937-10:2011 7 Table 1 Fields of burst-info (data-type=23, sub-data-type=0) Bits of Pc Value Contents Reference point R Repetition period of data-burst in IEC 60958 frames 0 to 4 data-type 0-22 In accordance with IEC 61937-2 23 MPEG-4 ALS or other applicat
36、ions according to IEC 61937-2, depending on sub-data-type Bit 0 of Pa See 5.2.1 24-31 In accordance with IEC 61937-2 5, 6 sub dat-type 0 1-3 MPEG-4 ALS In accordance with IEC 61937-2 See 5.2.1 7 0 1 Error-flag indicating a valid burst-payload Burst may contain errors 8 to 12 Dat-type and sub-dat-typ
37、e depndent information for MPEG-4 ALS 8 Multiplier 0 1 IEC 60958 frame rate = audio sampling rate 2 IEC 60958 frame rate = audio sampling rate 8 9 to 12 0000 0001 0010-1111 No indication ALS Simple Profile Level 1 Reserved for future Profile or Level 13 to 15 In accordance with IEC 61937-1 and IEC 6
38、1937-2. 5 Format of MPEG-4 ALS data-bursts 5.1 General This clause specifies the audio data-burst MPEG-4 ALS. 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),
39、indicated for the data-types, should be used by the transmitter to schedule data-bursts, as necessary, to establish synchronisation between video and decoded audio. 5.2 Audio data-bursts 5.2.1 Data-burst for MPEG-4 ALS Figure 1 shows the detailed description of the MPEG-4 ALS data-burst. The stream
40、of the data-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 with a burst-preamble, followed by the burst-payload, and stuffed with stuffing bits. The burst-payload of each data-burs
41、t 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 ALS bitstream, whose number of samples (per channel) is given in the field samples of (the corresponding) ALSSpecificConfig. The units of length-code
42、(burst_length) shall be in 8-bytes. BS EN 61937-10:2011 8 EN 61937-10:2011 Note that if the actual data size of the data-burst is not a multiple of 8 bytes, 1 to 7 stuffing bytes are included in the burst_length. The number of samples for each encoded channel contained in the data-burst are indicate
43、d in the encoded 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 number of samples of encoded audio per f
44、rame, may be found in ISO/IEC 14496-3, subpart 11. Figure 1 MPEG-4 ALS data-burst The regular rate of the MPEG-4 ALS frames and the repetition period of the data burst can be calculated as samples IEC 60958 frame rate/sampling frequency of the encoded audio samples (samp_freq). The value of the samp
45、les field is stored in the 9th to 12th bytes of the MPEG-4 ALS burst-payload. The value represents the number of samples contained in the MPEG-4 ALS burst-payload. The IEC 60958 frame rate is defined by the audio sampling rate and a value of the multiplier (see Table.2). The reference point of a MPE
46、G-4 ALS data-burst is bit 0 of Pa and occurs exactly once every predefined number of IEC 60958 frames. The data-burst containing MPEG-4 ALS frames shall occur at a regular rate, with the reference point of each MPEG-4 ALS data-burst beginning after the number of IEC 60958 frames in the previous MPEG
47、-4 ALS data-burst from the reference point of the preceding MPEG-4 ALS data-burst (of the same bit-stream-number). It is recommended that pause data-bursts be used to fill stream gaps in the MPEG-4 ALS bit stream as described in the IEC 61937-1, and that pause data-bursts be transmitted with a repet
48、ition period of 32 IEC 60958 frames, except when other repetition periods are necessary to fill the precise stream gap length (which may not be a multiple of 32 IEC 60958 frames), or to meet the requirement on burst spacing (see IEC 61937-1). When a stream gap in an MPEG-4 ALS stream is filled by a
49、sequence of pause data-bursts, the Pa of the first pause data-burst shall be located after a number of sampling periods represented by the samples field of the ALSSpecificConfig header in the previous MEG-4 ALS data-burst from the Pa of the previous MPEG-4 ALS frame. It is also recommended that the sequence(s) of pause data-bursts that fill the stream gap should continue from this point up to (as close as possible, considering the 32 IEC
