1、 ETSI TS 102 563 V2.1.1 (2017-01) Digital Audio Broadcasting (DAB); DAB+ audio coding (MPEG HE-AACv2) TECHNICAL SPECIFICATION ETSI ETSI TS 102 563 V2.1.1 (2017-01)2 Reference RTS/JTC-DAB-82 Keywords audio, broadcasting, coding, DAB, digital ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex
2、- FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice The present document can be downloaded from: http:/www.etsi.org/standards-search The present document may
3、be made available in electronic versions and/or in print. The content of any electronic and/or print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any existing or perceived difference in contents between such versions and/or in pri
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5、his and other ETSI documents is available at https:/portal.etsi.org/TB/ETSIDeliverableStatus.aspx If you find errors in the present document, please send your comment to one of the following services: https:/portal.etsi.org/People/CommiteeSupportStaff.aspx Copyright Notification No part may be repro
6、duced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm except as authorized by written permission of ETSI. The content of the PDF version shall not be modified without the written authorization of ETSI. The copyright and the foregoing restrictio
7、n extend to reproduction in all media. European Telecommunications Standards Institute 2017. European Broadcasting Union 2017. All rights reserved. DECTTM, PLUGTESTSTM, UMTSTMand the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members. 3GPPTM and LTE are Trade Marks of ETSI r
8、egistered for the benefit of its Members and of the 3GPP Organizational Partners. GSM and the GSM logo are Trade Marks registered and owned by the GSM Association. ETSI ETSI TS 102 563 V2.1.1 (2017-01)3 Contents Intellectual Property Rights 5g3Foreword . 5g3Modal verbs terminology 5g31 Scope 6g32 Re
9、ferences 6g32.1 Normative references . 6g32.2 Informative references 6g33 Definitions, abbreviations and arithmetic operators . 6g33.1 Definitions 6g33.2 Abbreviations . 7g33.3 Arithmetic operators . 7g34 Introduction 7g35 Audio 8g35.1 HE-AACv2 audio coding . 8g35.2 Audio super framing syntax . 9g35
10、.3 MPEG Surround . 12g35.3.1 Overview 12g35.3.2 Requirements for MPEG Surround encoders and decoders 13g35.3.3 Operational aspects of broadcasting . 13g35.3.4 Receiver implementation aspects 13g35.4 Programme Associated Data (PAD) . 14g35.4.0 Introduction. 14g35.4.1 PAD insertion . 14g35.4.2 Coding
11、of F-PAD and X-PAD 15g35.4.3 PAD extraction . 15g36 Transport error coding and interleaving . 16g36.0 Introduction 16g36.1 RS coding . 16g36.2 Formation of the coding array 17g36.3 Formation of the parity array 17g36.4 Formation of the output array . 17g36.5 Order of data transmission 17g37 Signalli
12、ng . 17g37.1 FIC signalling . 17g37.2 Audio parameter signalling 17g38 Reconfiguration 18g3Annex A (normative): Error concealment . 19g3A.0 Introduction 19g3A.1 AAC error concealment 19g3A.1.0 Introduction 19g3A.1.1 Interpolation of one corrupt AU . 19g3A.1.2 Fade-out and fade-in . 20g3A.2 SBR error
13、 concealment 20g3A.3 Parametric stereo error concealment 22g3A.4 MPEG Surround error concealment . 22g3Annex B (informative): Implementation tips for PAD insertion 23g3ETSI ETSI TS 102 563 V2.1.1 (2017-01)4 Annex C (informative): Synchronizing to the audio super frame structure . 24g3Annex D (inform
14、ative): Processing a super frame 26g3Annex E (informative): Bit-rate available for audio . 27g3History 28g3ETSI ETSI TS 102 563 V2.1.1 (2017-01)5 Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to
15、 these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. La
16、test updates are available on the ETSI Web server (https:/ipr.etsi.org/). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI
17、 Web server) which are, or may be, or may become, essential to the present document. Foreword This Technical Specification (TS) has been produced by Joint Technical Committee (JTC) Broadcast of the European Broadcasting Union (EBU), Comit Europen de Normalisation ELECtrotechnique (CENELEC) and the E
18、uropean Telecommunications Standards Institute (ETSI). NOTE 1: The EBU/ETSI JTC Broadcast was established in 1990 to co-ordinate the drafting of standards in the specific field of broadcasting and related fields. Since 1995 the JTC Broadcast became a tripartite body by including in the Memorandum of
19、 Understanding also CENELEC, which is responsible for the standardization of radio and television receivers. The EBU is a professional association of broadcasting organizations whose work includes the co-ordination of its members activities in the technical, legal, programme-making and programme-exc
20、hange domains. The EBU has active members in about 60 countries in the European broadcasting area; its headquarters is in Geneva. European Broadcasting Union CH-1218 GRAND SACONNEX (Geneva) Switzerland Tel: +41 22 717 21 11 Fax: +41 22 717 24 81 The Eureka Project 147 was established in 1987, with f
21、unding from the European Commission, to develop a system for the broadcasting of audio and data to fixed, portable or mobile receivers. Their work resulted in the publication of European Standard, ETSI EN 300 401 1, for DAB (see note 2) which now has worldwide acceptance. NOTE 2: DAB is a registered
22、 trademark owned by one of the Eureka Project 147 partners. The DAB family of standards is supported by World DAB, an organization with members drawn from broadcasting organizations and telecommunication providers together with companies from the professional and consumer electronics industry. Modal
23、 verbs terminology In the present document “shall“, “shall not“, “should“, “should not“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions). “must“ and “must not“ are NO
24、T allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TS 102 563 V2.1.1 (2017-01)6 1 Scope The present document defines the method to code and transmit audio services using the HE-AACv2 2 audio coder for Eureka-147 Digital Audio Broadcasting (DAB) (ETSI EN 300 401 1) and deta
25、ils the necessary mandatory requirements for decoders. The permitted audio modes and the data protection and encapsulation are detailed. This audio coding scheme permits the full use of the PAD channel for carrying dynamic labels and user applications. 2 References 2.1 Normative references Reference
26、s are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the referenced document (including any amendments) applies. Referenced docume
27、nts which are not found to be publicly available in the expected location might be found at https:/docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee their long term validity. The following referenced documents a
28、re necessary for the application of the present document. 1 ETSI EN 300 401 (V2.1.1): “Radio Broadcasting Systems; Digital Audio Broadcasting (DAB) to mobile, portable and fixed receivers“. 2 ISO/IEC 14496-3: “Information technology - Coding of audio-visual objects - Part 3: Audio“. 2.2 Informative
29、references References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the referenced document (including any amendments) applie
30、s. NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee their long term validity. The following referenced documents are not necessary for the application of the present document but they assist the user with regard to a particular subject a
31、rea. i.1 ISO/IEC 23003-1: “Information technology - MPEG audio technologies - Part 1: MPEG Surround“. 3 Definitions, abbreviations and arithmetic operators 3.1 Definitions For the purposes of the present document, the terms and definitions given in ETSI EN 300 401 1 and the following apply: access u
32、nit: access unit contains the audio samples for 20 ms, 30 ms, 40 ms or 60 ms of audio depending on the sampling rate of the AAC core, respectively 48 kHz, 32 kHz, 24 kHz or 16 kHz audio super frame: audio super frame contains a number of AUs which together contain the encoded audio for 120 ms ETSI E
33、TSI TS 102 563 V2.1.1 (2017-01)7 subchannel_index: subchannel_index is derived from the size of the sub-channel carrying the audio service and defines the number of Reed-Solomon code words in each audio super frame 3.2 Abbreviations For the purposes of the present document, the abbreviations given i
34、n ETSI EN 300 401 1 and the following apply: AAC Advanced Audio Coding AU Access Unit CRC Cyclic Redundancy Check CU Capacity Unit DAB Digital Audio Broadcasting DAC Digital Analogue Converter DMB Digital Multimedia Broadcasting DRC Dynamic Range Control DVB Digital Video Broadcasting FIC Fast Infor
35、mation Channel FIG Fast Information Group GF Galois Field HE-AAC High Efficiency AAC MCI Multiplex Configuration Information MPEG Moving Pictures Experts Group MSC Main Service Channel PAD Programme Associated Data PS Parametric Stereo RS Reed-SolomonSAC Spatial Audio Coding SBR Spectral Band Replic
36、ation 3.3 Arithmetic operators + addition - subtraction multiplication division m DIV p denotes the quotient part of the division of m by p (m and p are positive integers) m MOD p denotes the remainder of the division of m by p (m and p are positive integers) ()=qpiif denotes the sum: f(p) + f(p + 1
37、) + f(p + 2) . + f(q) ()=qpiif denotes the product: f(p) f(p + 1) f(p + 2) . f(q) 4 Introduction The DAB system standard 1 allows audio (programme) services to be carried using either DAB audio or DAB+ audio. The present document defines the way that audio (programme) services are carried when using
38、 DAB+ audio (MPEG 4 HE-AACv2 audio coding). MPEG 4 HE-AACv2 specifies two transforms, but only the 960 transform is permitted for DAB+ audio, with core sampling rates of 48 kHz, 32 kHz, 24 kHz and 16 kHz. Each AU (audio frame) contains samples for 20 ms, 30 ms, 40 ms or 60 ms respectively. AUs are b
39、uilt into audio super frames of 120 ms duration which are then carried in five DAB logical frames. In order to provide additional error control, Reed Solomon coding and virtual interleaving is applied. The overall scheme is shown in figure 1. ETSI ETSI TS 102 563 V2.1.1 (2017-01)8 HE AAC v2 audio co
40、der Scope of present document Reed-Solomon coder and virtual interleaver DAB main service channel multiplexer Audio super framing Figure 1: Conceptual diagram of the outer coder and interleaver 5 Audio 5.1 HE-AACv2 audio coding For generic audio coding, a subset of the MPEG-4 High Efficiency Advance
41、d Audio Coding v2 (HE-AACv2) profile chosen to best suit the DAB system environment is used. The HE-AACv2 Profile, Level 2 according to 2 shall apply with the following additional restrictions for the DAB system: Sampling rates: permitted output sampling rates of the HE-AACv2 decoder are 32 kHz and
42、48 kHz, i.e. when SBR is enabled the AAC core shall be operated at 16 kHz or 24 kHz, respectively. If SBR is disabled then the AAC core shall be operated at 32 kHz or 48 kHz respectively. Transform length: the number of samples per channel per AU is 960. This is required to harmonize HE-AAC AU lengt
43、hs to allow the combination of an integer number of AUs to build an audio super frame of 120 ms duration. Audio bit rates are restricted to fit within a maximum sub-channel size of 192 kbps (approximately 175 kbps for audio, assuming no PAD). Audio super framing: AUs are composed into audio super fr
44、ames, which always correspond to 120 ms in time. The AUs in the audio super frames are encoded together such that each audio super frame is of constant length, i.e. that bit exchange between AUs is only possible within an audio super frame. The number of AUs per super frame are: two (16 kHz AAC core
45、 sampling rate with SBR enabled), three (24 kHz AAC core sampling rate with SBR enabled), four (32 kHz AAC core sampling rate) or six (48 kHz AAC core sampling rate). Each audio super frame is carried in five consecutive logical DAB frames (see clause 7) which enables simple synchronization and mana
46、gement of reconfigurations. The size of the audio super frame is defined by the size of the MSC sub-channel (see ETSI EN 300 401 1, clause 6.2.1) which carries the audio super frame. Sub-channels are multiples of 8 kbps in size. The size of the audio super frame in bytes is given by the expressions
47、below: subchannel_index = MSC sub-channel size (kbps) 8 audio_super_frame_size (bytes) = subchannel_index 110 The first byte of the audio super frame is byte 0 and the last byte is byte (audio_super_frame_size - 1). NOTE: The subchannel_index parameter may take the values 1 to 24 due to the restrict
48、ion limiting the maximum sub-channel size to 192 kbps. ETSI ETSI TS 102 563 V2.1.1 (2017-01)9 5.2 Audio super framing syntax Table 1: Syntax of he_aac_super_frame() Syntax No. of bits Note he_aac_super_frame(subchannel_index) he_aac_super_frame_header() determines num_aus for (n = 0; n =2QL ()00Et()
49、16EEL t() ( )1,0E EEl llL+11EQLANDL=ETSI ETSI TS 102 563 V2.1.1 (2017-01)22 all elements of tQare not among the elements of tEIf the plausibility check fails, the AU error flag is set and the error concealment outlined above is applied. Figure A.1: SBR error concealment overview A.3 Parametric stereo error concealment Parametric stereo error concealment is based on the fact that the stereo image is quasi stationary. The concealment strategy keeps the Parametric Stereo settings from the last valid AU until a new
