AAC-ISO-13818-7(2014).pdfMPEG2_AAC的（2004年）第三版，ISO/

文件名称: AAC-ISO-13818-7(2014).pdf

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详细说明：MPEG2_AAC的（2004年）第三版，ISO/IEC 14496－3（MPEG4_AAC）直接来自于ISO/IEC 13818－7，所以在14496－3中有些东西可能看不懂或不知道渊源，都可以在这里找到。在文件格式上，13818－7定义的是*.AAC为后缀的文件（ADTS是其中一种）。14496－3则定义的是*.MP4格式，而apple推出的*.M4A则是*.MP4除ISO/EO13818-7:2004(E Contents Page Scope 1.1 MPEG-2 AAC Tools Overview Normative references…… Terms and definitions 4 Symbols and Abbreviations…,,…,…,…,…,…,…,……,…,…,………,…,…,……………………15 4.1 Arithmetic Operators 4.2 Logical Operators Relational Operators .16 Bitwise Operators 8画面面 4.5 Assignment 4.6 Mnemonics 11 4.7 Constants ∴17 Method of Describing Bitstream Syntax,,,…,…,…,…,…,…,……,,…,…,………,…17 Syntax………,…,…,…,…,…,…,…,…,…,…,…,…,…,…,…,…,……,…,…,…,…,……19 Audio data Interchange format, ADIF 19 62 Audio data Transport Strean,ADTS...………20 6.3 Raw dat 22 Profiles and profile Interoperability…,…, 34 7.1 Profiles∴ 34 7.2 Profile Interoperability 36 General Information iB面 37 1 Audio Data Interchange Format (ADIF)and Audio Data Transport Stream(ADTS) 37 8.2 Decoding of Raw Data 42 8.3 Decoding of a single_channel_element((SCE), a channel_pair_element()(CPE)or an individual_ channel_stream((ICS) 8. 4 Low Frequency Enhancement Channel (LFE) 54 8.5 program_config_element((PCE) 8.6 Data Stream Element (DSE) 59 8.7 Fill element(FlL)… 8.8 Dedoding of extension_payload) 60 8.9 Tables 66 8. 10 Figures Noiseless Coding……,,,,,,…,,…,,…,…, 74 9.1 Tool Description 74 9.2 Definitions 75 9.3 Decoding Process 77 9. 4 Tables 80 Quantization 10.1 Tool Description .81 10.2 Definitions 81 10.3 Decoding Process Scalefactor 82 icA八.nnA All rights reserved ISO/EC13818-7:2004E) ool Description 82 11.2Def∩tonS. 82 11.3 Decoding Process 83 12 Joint Coding 84 12. M/S Stereo 84 12.2 Intensity Stereo 86 12.3 Coupling channel 88 13 Prediction D111日日日面重面国面国日日面面 …92 13.1 Tool Description 92 13.2 Definitions 92 13.3 Decoding process 13.4 Diagrams 14 Temporal Noise Shaping(TNS)….,,,,,,…… 100 14.1 Tool Description 100 142 Definitions 101 14.3 Decoding Process 101 15 Filterbank and Block Switching 103 15.1 Tool Description .103 15.2 Definitions 103 15.3 Decoding Process .104 16 Gain Control 108 16.1 Tool Description 16.2 Definitions 109 16.3 Decoding process .109 164 Diagrams… 115 16.5 Tables 115 Annex A( normative) Huffman codebook tables…… 117 AnnexB(informative) nformation on unused codebooks………… 138 Annex( informative) Encoder…… 139 C 1 Psychoacoustic Model 139 C2 Gain Control 171 C 3 Filterbank and Block Switching 172 C 4 Prediction 175 C5 Temporal Noise Shaping(TNS) 178 C 6 Joint Coding 7 Quantization 181 C8 Noiseless Coding 188 C 9 Features of aac dynamic range control 191 AnnexD( informative) Patent Holders…… 193 D.1 List of patent holders 193 Annex E( informative) Registration Procedure.....….….………194 E1 Procedure for the Request of a Registered Identifier(RID 194 E2 Responsibilities of the registration authorit 194 E.3 contact Information of the Registration Ar 194 E4 Responsibilities of Parties Requesting a RID 195 E 5 Appeal procedure for Denied Applications 195 Annex F(informative)Registration Application Form 196 Annex G(informative) Registration Authority. ∴197 Bibliography…….….….… 198 AI八A.△△A "ights reserve ISO/EO13818-7:2004(E Foreword ISo(the International Organization for Standardization is a worldwide federation of national standards bodies (Iso member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISo, also take part in the work. ISO collaborates closely with the International Electrotechnical commission(lEc)on all matters of electrotechnical standardization International Standards are drafted in accordance with the rules given in the iSo/EC Directives, Part 2 The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75/ of the member bodies casting a vote ISO/EC 13818-7 was prepared by Joint Technical Committee ISO/EC JTC1, Information technology. Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information technically revised It also incorporates the Amendment ISO/EC 13818-7: 2003/Amd 1: 2004 lh This third edition cancels and replaces the second edition (ISo/EC 13818-7: 2003) hich has been ISO/EC 13818 consists of the following parts, under the general title Information technology - Generic coding of moving pictures and associated audio information Part 1: Systems Part 2: video Part 3: Audio Part 4: Conformance testing Part 5: Software simulation Part 6: Exten sions for DSm-cc Part 7: Advanced Audio Coding(AAC) Part 9: Extension for real time interface for systems decoders Part 10: Conformance extensions for Digital Storage Media Command and Control (DSM-CC) - Part 11: /PMP on MPEG-2 systems icA八.nnA All rights reserved ISO/EC13818-7:2004(E) Introduction The standardization body ISO/EC JTC 1/SC 29/G 11, also known as the Moving Pictures Experts Group (MPEG), was established in 1988 to specify digital video and audio coding schemes at low data rates. MPEG completed its first phase of audio specifications(MPEg-1)in November 1992, ISo/EC 11172-3. In its second phase of development, the MPEG Audio subgroup defined a multichannel extension to mPEG-1 audio that is backwards compatible with existing MPEG-1 systems(MPEG-2 BC) and defined an audio coding standard at lower sampling frequencies than MPEG-1, ISO/EC 13818-3 The International Organization for Standardization(ISO) and International Electrotechnical Commission(IEC) draw attention to the fact that it is claimed that compliance with this document may involve the use of patents The iso and iC take no position concerning the evidence, validity and scope of this patent right The holder of this patent right has assured the iso and iec that he is willing to negotiate licences under reasonable and non-discriminatory terms and conditions with applicants throughout the world. In this respect, the statement of the holder of this patent right is registered with the ISo and IEC. Information may be obtained from the companies listed in Annex D Attention is drawn to the possibility that some of the elements of this document may be the subject of patent ights other than those identified in Annex D ISo and IEC shall not be held responsible for identifying any or all such patent rights AI八A.△△A "ights reserve INTERNATIONAL STANDARD sO/Ec13818-7:2004(E) Information technology-Generic coding of moving pictures and associated audio information Part 7 Advanced Audio Coding(AAC) Scope This International Standard describes the mPeG-2 audio non -backwards compatible standard called MPEG-2 Advanced Audio Coding, AAc [1], a higher quality multichannel standard than achievable while requiring MPEG-1 backwards compatibility. This MPEG-2 AAC audio standard allows for ITU-R indistinguishable quality according to [2] at data rates of 320 kbit/s for five full-bandwidth channel audio signals The aac decoding process makes use of a number of required tools and a number of optional tools. Table 1 lists the tools and their status as required or optional. Required tools are mandatory in any possible profile. Optional tools may not be required in some profiles 1.1 MPEG-2 AAC Tools Overview The basic structure of the MPEG-2 AAC system is shown in Figure 1 and Figure 2. As is shown in Table 1, there are both required and optional tools in the decoder. The data flow in this diagram is from left to right, top to bottom. The functions of the decoder are to find the description of the quantized audio spectra in the bitstream, decode the quantized values and other reconstruction information, reconstruct the quantized spectra, process the reconstructed spectra through whatever tools are active in the bitstream in order to arrive at the actual signal spectra as described by the input bitstream, and finally convert the frequency domain spectra to the time domain, with or without an optional gain control tool Following the initial reconstruction and scaling of the spectrum reconstruction, there are many optional tools that modify one or more of the spectra in order to provide more efficient icA八.nnA All rights reserved ISO/EC13818-7:2004E) coding. For each of the optional tools that operate in the spectral domain, the option to spectra at its input are passed directly through the tool without modification. u pass through"is retained, and in all cases where a spectral operation omitted. the The input to the bitstream demultiplexer tool is the MPEG-2 Aac bitstream The demultiplexer separates the parts of the MPEG-Aac data stream into the parts for each tool, and provides each of the tools with the bitstream information related to that tool The outputs from the bitstream demultiplexer tool are The sectioning information for the noiselessly coded spectra The noiselessly coded spectra The M/s decision information(optional) The predictor state information(optional) The intensity stereo control information and coupling channel control information (both optional) The temporal noise shaping (tNs)information(optional) The filterbank control information The gain control information(optional) The noiseless decoding tool takes information from the bitstream demultiplexer, parses that information, decodes the Huffman coded data, and reconstructs the quantized spectra and the huffman and dpcm coded scalefactor The inputs to the noiseless decoding tool are The sectioning information for the noiselessly coded spectra The noiselessly coded spectra The outputs of the Noiseless Decoding tool are The decoded integer representation of the scalefactor: The quantized values for the spectra The inverse quantizer tool takes the quantized values for the spectra, and converts the integer values to the non-scaled, reconstructed spectra. This quantizer is a non-uniform quantizer. The input to the Inverse Quantizer tool is The quantized values for the spectra The output of the inverse quantizer tool is The un-scaled, inversely quantized spectra AI八A.△△A "ights reserve ISO/EO13818-7:2004(E The rescaling tool converts the integer representation of the scalefactor to the actual values, and multiplies the un-scaled inversely quantized spectra by the relevant scalefactor The inputs to the rescaling tool are The decoded integer representation of the scalefactor The un-scaled, inversely quantized spectra The output from the scalefactor tool is The scaled, inversely quantized spectra The M/s tool converts spectra pairs from Mid/Side to Left/ Right under control of the M/s decision information in order to improve coding efficiency The inputs to the M/S tool are The ms decision information The scaled, inversely quantized spectra related to pairs of channels The output from the M/s tool is The scaled, inversely quantized spectra related to pairs of channels, after M/s decoding Note: The scaled, inversely quantized spectra of individually coded channels are not processed by the M/s block, rather they are passed directly through the block without modification. If the m/s block is not active, all spectra are passed through this block unmodified The prediction tool reverses the prediction process carried out at the encoder. This prediction process re-inserts the redundancy that was extracted by the prediction tool at the encoder, under the control of the predictor state information. This tool is implemented as a second order backward adaptive predictor. The inputs to the prediction tool are The predictor state information The scaled, inversely quantized spectra The output from the prediction tool is The scaled, inversely quantized spectra, after prediction is applied Note: If the prediction is disabled, the scaled, inversely quantized spectra are passed directly through the block without modification The intensity stereo tool implements intensity stereo decoding on pairs of spectra The inputs to the intensity stereo tool are The inversely quantized spectra The intensity stereo control information The output from the intensity stereo tool is The inversely quantized spectra after intensity channel decoding Note: The scaled, inversely quantized spectra of individually coded channels are passed directly through this tool without modification, if intensity stereo is not indicated. The intensity stereo tool and m/s tool are arranged so that the operation of M/'s and intensity stereo are mutually exclusive on any given scalefactor band and group of one pair of spectra icA八.nnA All rights reserved ISO/EC13818-7:2004E) The coupling tool for dependently switched coupling channels adds the relevant data from dependently switched coupling channels to the spectra, as directed by the coupling control information The inputs to the coupling tool are The inversely quantized spectra The coupling control information The output from the coupling tool is The inversely quantized spectra coupled with the dependently switched coupling channels Note: The scaled, inversely quantized spectra are passed directly through this tool without modification, if coupling is not indicated Depending on the coupling control information, dependently switched coupling channels might either be coupled before or after the TNs processing The coupling tool for independently switched coupling channels adds the relevant data from independently switched coupling channels to the time signal, as directed by the coupling control information The inputs to the coupling tool are The time signal as output by the filterbank The coupling control information The output from the coupling tool is The time signal coupled with the independently switched coupling channels Note: The time signal is passed directly through this tool without modification, if coupling is not indicated The temporal noise shaping tns) tool implements a control of the fine time structure of the coding noise. In the encoder, the tNs process has flattened the temporal envelope of the signal to which it has been applied In the decoder, the inverse process is used to restore the actual temporal envelope(s), under control of the TNs information. This is done by applying a filtering process to parts of the spectral data The inputs to the tns tool are the inversely quantized spectra ● The tns information The output from the tns block is The inversely quantized spectra Note: If this block is disabled, the inversely quantized spectra are passed through without modification The filterbank/ block switching tool applies the inverse of the frequency mapping that was carried out in the encoder. An inverse modified discrete cosine transform(IMDCT)is used for the filterbank tool. The IMDCT can be configured to support either one set of 128 or 1024, or four sets of 32 or 256 spectral coefficients AI八A.△△A "ights reserve

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