1、 ETSI TS 102 563 V1.2.1 (2010-05)Technical Specification Digital Audio Broadcasting (DAB);Transport of Advanced Audio Coding (AAC) audioEuropean Broadcasting Union Union Europenne de Radio-Tlvision EBUUER ETSI ETSI TS 102 563 V1.2.1 (2010-05)2Reference RTS/JTC-DAB-64 Keywords audio, broadcasting, co
2、ding, DAB, digital ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - 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 Individual copies of the pre
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6、d by written permission. The copyright and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2010. European Broadcasting Union 2010. All rights reserved. DECTTM, PLUGTESTSTM, UMTSTM, TIPHONTM, the TIPHON logo and the ETSI logo are Trade Ma
7、rks of ETSI registered for the benefit of its Members. 3GPPTM is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. LTE is a Trade Mark of ETSI currently being registered for the benefit of its Members and of the 3GPP Organizational Partners. GSM
8、and the GSM logo are Trade Marks registered and owned by the GSM Association. ETSI ETSI TS 102 563 V1.2.1 (2010-05)3Contents Intellectual Property Rights 4g3Foreword . 4g31 Scope 5g32 References 5g32.1 Normative references . 5g32.2 Informative references 5g33 Definitions, abbreviations and arithmeti
9、c operators . 6g33.1 Definitions 6g33.2 Abbreviations . 6g33.3 Arithmetic operators . 6g34 Introduction 7g35 Audio 7g35.1 HE AAC v2 audio coding 7g35.2 Audio super framing syntax . 8g35.3 MPEG Surround . 11g35.3.1 Overview 11g35.3.2 Requirements for MPEG Surround encoders and decoders 12g35.3.3 Oper
10、ational aspects of broadcasting . 12g35.3.4 Receiver implementation aspects 12g35.4 Programme Associated Data (PAD) . 13g35.4.1 PAD insertion . 13g35.4.2 Coding of F-PAD and X-PAD 14g35.4.3 PAD extraction . 14g36 Transport error coding and interleaving . 15g36.1 RS coding . 15g36.2 Formation of the
11、coding array 16g36.3 Formation of the parity array 16g36.4 Formation of the output array . 16g36.5 Order of data transmission 16g37 Signalling . 16g37.1 FIC signalling . 16g37.2 Audio parameter signalling 17g38 Re-configuration . 17g3Annex A (normative): Error concealment . 18g3A.1 AAC error conceal
12、ment 18g3A.1.1 Interpolation of one corrupt AU . 18g3A.1.2 Fade-out and fade-in . 19g3A.2 SBR error concealment 19g3A.3 Parametric stereo error concealment 21g3A.4 MPEG Surround error concealment . 21g3Annex B (informative): Implementation tips for PAD insertion 22g3Annex C (informative): Synchroniz
13、ing to the audio super frame structure . 23g3Annex D (informative): Processing a super frame 25g3Annex E (informative): Bit-rate available for audio . 26g3History 27g3ETSI ETSI TS 102 563 V1.2.1 (2010-05)4Intellectual Property Rights IPRs essential or potentially essential to the present document ma
14、y have been declared to ETSI. The information pertaining to 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 s
15、tandards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http:/webapp.etsi.org/IPR/home.asp). 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
16、 other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI 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 (
17、EBU), Comit Europen de Normalisation ELECtrotechnique (CENELEC) and the European 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
18、 JTC Broadcast became a tripartite body by including in the Memorandum of 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 membe
19、rs activities in the technical, legal, programme-making and programme-exchange 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
20、: +41 22 717 24 81 The Eureka Project 147 was established in 1987, with funding 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, EN 300 401 1, for DAB (see not
21、e 2) which now has worldwide acceptance. The members of the Eureka Project 147 are drawn from broadcasting organizations and telecommunication providers together with companies from the professional and consumer electronics industry. NOTE 2: DAB is a registered trademark owned by one of the Eureka P
22、roject 147 partners. ETSI ETSI TS 102 563 V1.2.1 (2010-05)51 Scope The present document defines the method to code and transmit audio services using the HE AAC v2 2 audio coder for Eureka-147 Digital Audio Broadcasting (DAB) (EN 300 401 1) and details the necessary mandatory requirements for decoder
23、s. 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 References are either specific (identified by date of publication and/or edition numbe
24、r or version number) or non-specific. For a specific reference, subsequent revisions do not apply. Non-specific reference may be made only to a complete document or a part thereof and only in the following cases: - if it is accepted that it will be possible to use all future changes of the reference
25、d document for the purposes of the referring document; - for informative references. Referenced documents which are not found to be publicly available in the expected location might be found at http:/docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the time
26、 of publication ETSI cannot guarantee their long term validity. 2.1 Normative references The following referenced documents are indispensable for the application of the present document. For dated references, only the edition cited applies. For non-specific references, the latest edition of the refe
27、renced document (including any amendments) applies. 1 ETSI EN 300 401: “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 references The
28、following referenced documents are not essential to the use of the present document but they assist the user with regard to a particular subject area. For non-specific references, the latest version of the referenced document (including any amendments) applies. i.1 ETSI TR 101 496-2: “Digital Audio
29、Broadcasting (DAB); Guidelines and rules for implementation and operation; Part 2: System features“. i.2 ISO/IEC 23003-1: “Information technology - MPEG audio technologies - Part 1: MPEG Surround“. ETSI ETSI TS 102 563 V1.2.1 (2010-05)63 Definitions, abbreviations and arithmetic operators 3.1 Defini
30、tions For the purposes of the present document, the terms and definitions given in EN 300 401 1 and the following apply: access unit: 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 o
31、r 16 kHz audio super frame: audio super frame contains a number of AUs which together contain the encoded audio for 120 ms 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 f
32、rame 3.2 Abbreviations For the purposes of the present document, the abbreviations given in EN 300 401 1 and the following apply: AAC Advanced Audio Coding AU Access Unit DAC Digital Analogue Converter DMB Digital Multimedia Broadcasting DVB Digital Video Broadcasting HE AAC High Efficiency AAC PS P
33、arametric StereoRS Reed-SolomonSBR Spectral Band Replication 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 positi
34、ve integers) ()=qpiif denotes the sum: f(p) + f(p + 1) + f(p + 2) . + f(q) ()=qpiif denotes the product: f(p) f(p + 1) f(p + 2) . f(q) ETSI ETSI TS 102 563 V1.2.1 (2010-05)74 Introduction The DAB system standard 1 defines the way that audio (programme) services are carried when using MPEG Layer II.
35、The present document defines the way that audio (programme) services are carried when using MPEG 4 HE AAC v2. For Layer II audio, two sampling rates are permitted, 48 kHz and 24 kHz. Each audio frame contains samples for 24 ms or 48 ms respectively and each contains the same number of bytes. The aud
36、io frames are carried in one or two respectively DAB logical frames. For AAC, two transforms are specified. For DAB, only the 960 transform is permitted with 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. In
37、order to provide a similar architectural model to Layer II audio, and simple synchronization, AUs are built into audio super frames of 120 ms 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
38、overall scheme is shown in figure 1. HE AAC v2 audio coder 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 AAC v2 audio coding For generic audi
39、o coding, a subset of the MPEG-4 High Efficiency Advanced Audio Coding v2 (HE AAC v2) profile chosen to best suit the DAB system environment is used. The HE AAC v2 Profile, Level 2 according to 2 shall apply with the following additional restrictions for the DAB system: Sampling rates: permitted out
40、put sampling rates of the HE AAC v2 decoder are 32 kHz and 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 p
41、er AU is 960. This is required to harmonize HE AAC AU lengths 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)
42、. Audio super framing: AUs are composed into audio super frames, 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.
43、The number of AUs per super frame are: two (16 kHz AAC core 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). ETSI ETSI TS 102 563 V1.2.1 (2010-05)8Each audio super frame is carried in
44、 five consecutive logical DAB frames (see clause 7) which enables simple synchronization and management of reconfigurations. The size of the audio super frame is defined by the size of the MSC sub-channel (see 1, clause 6.2.1) which carries the audio super frame. Sub-channels are multiples of 8 kbps
45、 in size. The size of the audio super frame in bytes is given by the expressions 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:
46、 The subchannel_index parameter may take the values 1 to 24 due to the restriction limiting the maximum sub-channel size to 192 kbps. 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() determ
47、ines num_aus for (n = 0; n = - 2QL - ()00Et - ()16EEL t - () ( )1,0E EEl llL+ - 11EQLANDL= - () ()00QEtt - () ()Q QEEL Ltt - () ( )1,0Q QQl llL+tt - 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
48、 applied. ETSI ETSI TS 102 563 V1.2.1 (2010-05)21frameErrorNoYesGenerateConcealing controldataaddConcealing-EnvelopeDatadeltaToLinear-PCMEnvelope-DecodingtimeCompensate-FirstEnvelopeprevFrame-ErrorFlagYesNodeltaToLinear-PCMEnvelope-Decodingcheck dataset frame errorflagerrorYes Norequantise-EnvelopeD
49、atareturncoupling =prevCouplingBeginFigure 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 set of Parametric Stereo settings can be decoded from a valid AU. A.4 MPEG Surround error concealment MPEG Surround error concealment is based on the fact that the surround image is quasi st
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