1、COVERING NOTE GENERAL SECRETARIAT INTERNATIONAL TELECOMMUNICATION UNION Geneva, 29 June2004 ITU -TELECOMMUNICATION STAN DARD IZAT I O N SECTOR Subject: Erratum 1 (06/2004) to ITU-T Recommendation G.722.2 (07/2003), Wideband coding of speech at around 16 kbith using Adaptive Multi-Rate Wideband (AMR-
2、 WB) In 5.2.5, Quantization of the ISP coefficients Correct the text as follows: . . . The prediction residual vector r(n) is given by: r(n = Z(.-P(. (22) where p(n) is the predicted WE vector at frame n. First-order MA prediction is used where: 1, p(n)=-r(n-i) 3 where F(n - 1) is the quantized resi
3、dual vector at the past frame. . Union internationale des telecommunications Place des Nations 121 1 GENEVE 20 Suisse - Switzerland - Suiza INTERNATIONAL TELECOMMUNICATION UNION ITU-T TE LEC0 M M U N I CATI ON STANDARDIZATION SECTOR OF ITU G.722.2 (07/2003) SERIES G: TRANSMISSION SYSTEMS AND MEDIA,
4、DIGITAL SYSTEMS AND NETWORKS Digital terminal equipments - Coding of analogue signals by methods other than PCM Wideband coding of speech at around 16 kbit/s using Adaptive Multi-rate Wideband (AMR-WB) CAUTION ! PREPUBLISHED RECOMMENDATION This prepublication is an unedited version of a recently app
5、roved Recommendation. Itwill be replaced by the published version after editing. Therefore, there will be differences between this prepublication and the published version. FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunica
6、tions. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunicati
7、on Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of inf
8、ormation technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating ag
9、ency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some
10、 other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or i
11、mplementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development pro
12、cess. As of the date of approval of this Recommendation, ITU hadihad not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore st
13、rongly urged to consult the TSB patent database. O ITU 2004 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. INTERNATIONAL TELECOMMUNICATION UNION ITU-T TE LEC0 M M U N I CATI ON STANDARDIZATION SECTOR OF ITU G.
14、722.2 (O1 /2002) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital terminal equipments - Coding of analogue signals by methods other than PCM Wideband coding of speech at around 16 kbit/s using Adaptive Multi-rate Wideband (AMR-WB) ITU-T Recommendation G.722.2 ITU-T Rec.
15、 G.722.2 (07/2003) - Prepublished version 1 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL, TELEPHONE CONNECTIONS AND CIRCUITS GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER- TRANSMISSION SYSTEMS INDIVIDUAL, CHARACTERISTICS OF INTERN
16、ATIONAL, CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G. 1 OM. 199 G.20M.299 G.30M.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE METALLIC LINES G.40M.449 SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY TESTING EQUIP
17、MENTS TRANSMISSION MEDIA CHARACTERISTICS DIGITAL, TERMINAL, EQUIPMENTS General G.45M.499 G.50M.599 G.60M.699 G.70M.799 G.70M.709 Coding of analogue signals by pulse code modulation Principal characteristics of primary multiplex equipment G.7 1 M.7 19 G.73M.739 Principal characteristics of second ord
18、er multiplex equipment Principal characteristics of higher order multiplex equipment Principal characteristics of transcoder and digital multiplication equipment Operations, administration and maintenance features of transmission equipment Principal characteristics of multiplexing equipment for the
19、synchronous digital hierarchy Other terminal equipment DIGITAL, NETWORKS DIGITAL, SECTIONS AND DIGITAL, LINE SYSTEM G.74M.749 G.75M.759 G.76M.769 G.77M.779 G.78M.789 G.79M.799 G.80M.899 G.90M.999 For further details, please refe. to the list of ITU-T Recommendations. ITU-T Rec. G.722.2 (07/2003) - P
20、republished version 2 ITU-T Recommendation G.722.2 Wideband coding of speech at around 16 kbits using Adaptive Multi-rate Wideband (AMR-WB) Summary This Recommendation describes the high quality Adaptive Multi-rate Wideband (AMR-WB) encoder and decoder that is primarily intended for 7 kHz bandwidth
21、speech signals. AMR-WB operates at a multitude of bit rates ranging fi-om 6.6 kbith to 23.85 kbith. The bit rate may be changed at any 20 ms fi-ame boundary. Annex C of this Recommendation includes an integrated C source code software package which contains the implementation of the G.722.2 encoder
22、and decoder and its Annexes A and B and Appendix I. A set of digital test vectors for developers is provided in Annex D. These test vectors are a verification tool providing an indication of success in implementing this codec. G.722.2 AMR-WB is the same codec as the 3GPP AMR-WB. The corresponding 3G
23、PP specifications are TS 26.190 for the speech codec and TS 26.194 for the Voice Activity Detector. Source ITU-T Recommendation G.722.2 was prepared by ITU-T Study Group 16 (2001-2004) and approved under the WTSA Resolution 1 procedure on 13 January 2002. ITU-T Rec. G.722.2 (07/2003) - Prepublished
24、version 3 FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff ques
25、tions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendation
26、s on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation,
27、the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claim
28、ed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by IT members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had rec
29、eived notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 2002 All rights reser
30、ved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. G.722.2 (07/2003) - Prepublished version 4 CONTENTS Scope Normative references . Definitions. symbols and abbreviations . 3.1 Definitions 3.2 Symbols 3.3 Abbreviations
31、 . Outline description . 4.1 4.2 4.3 4.4 4.5 Functional description of audio parts . Preparation of speech samples . Principles of the adaptive multirate wideband speech encoder Principles of the adaptive multirate speech decoder Sequence and subjective importance of encoded parameters Functional de
32、scription of the encoder 5.1 5.2 5.2.1 5.2.2 5.2.3 5.2.4 5.2.5 5.2.6 5.3 5.4 5.4.1 5.4.2 5.5 5.6 5.7 5.8 5.8.1 5.8.2 5.8.3 5.9 5.10 5.1 1 Preprocessing . Linear prediction analysis and quantization . Windowing and autocorrelation computation Levinson-Durbin algorithm LP to ISP conversion ISP to LP c
33、onversion Quantization of the ISP coefficients . Interpolation of the ISPs . Perceptual weighting Open-loop pitch analysis 6.60 kbit/s mode . 8.85, 12.65, 14.25, 15.85, 18.25, 19.85,23.05 and23.85 kbith modes . Impulse response computation . Target signal computation Adaptive codebook . Algebraic co
34、debook Codebook structure Pulse indexing Codebook search Quantization of the adaptive and fmed codebook gains High-band gain generation . Memory update Page 1 2 2 2 3 7 7 7 8 8 13 15 15 15 15 16 16 17 18 19 20 20 21 21 22 23 23 23 26 26 29 33 37 38 38 ITU-T Rec . G.722.2 (07/2003) - Prepublished ver
35、sion 5 6 7 8 9 10 Functional description of the decoder High-pass filtering. up-scaling and interpolation . Generation of high-band excitation LP filter for the high frequency band . 6.3.3 High band synthesis . 6.1 Decoding and speech synthesis 6.2 6.3 High frequency band 6.3.1 6.3.2 Detailed bit al
36、location of the adaptive multi-rate wideband codec Homing sequences 8.1 Functional description 8.3 Encoder homing . 8.4 Decoder homing . 8.2 Definitions Voice Activity Detector (VAD) . 9.1 VAD Symbols 9.1.1 VAD Variables . 9.1.2 VAD Constants 9.1.3 Functions 9.2 Functional description Filter bank an
37、d computation of sub-band levels 9.2.1 9.2.2 Tone detection 9.2.3 VAD decision . Bibliography . Page 39 39 42 42 42 43 43 44 52 52 53 53 53 54 54 54 54 55 56 56 59 59 63 ITU-T Rec . G.722.2 (07/2003) - Prepublished version 6 ITU-T Recommendation G.722.2 Wideband coding of speech at around 16 kbits u
38、sing Adaptive Multi-rate Wideband (AMR-WB) 1 Scope This Recommendation describes the detailed mapping fi-om input blocks of 320 speech samples in 16-bit uniform PCM format to encoded blocks of 132, 177, 253, 285, 317, 365, 397, 461 and 477 bits and fi-om encoded blocks of 132, 177,253,285, 317,365,3
39、97,461 and 477 bits to output blocks of 320 reconstructed speech samples. The sampling rate is 16 O00 samplesh leading to a bit rate for the encoded bit stream of 6.60, 8.85, 12.65, 14.25, 15.85, 18.25, 19.85, 23.05 or 23.85 kbith. The coding scheme for the multi-rate coding modes is the so-called A
40、lgebraic Code Excited Linear Prediction Coder, hereafter referred to as ACELP. The multi-rate wideband ACELP coder is referred to as AMR-WB. The codec described in this Recommendation also utilizes an integrated Voice Activity Detector (VAD). The foreseen applications for this Recommendation are the
41、 following: Voice over IP (VoIP) and Internet applications, Mobile Communications, PSTN applications, ISDN wideband telephony, ISDN videotelephony and video-conferencing. In addition to the algorithm specified in the main body of Recommendation G.722.2, Annexes A and B and Appendix I provide supplem
42、ental functionalities allowing interoperability with GSM and 3GPP wireless systems. These functionalities have originally been developed for these systems, but their use is not limited to mobile applications. Two other Annexes D and E describe test vectors and fi-ame structure respectively. These an
43、nexes may be implemented independently of this main body specification according to the different requirements of systems deploying the AMR-WB algorithm: controlled rate operation. The implementation of this annex is essential for interoperability with GSM and 3GPP wireless systems. implementation o
44、f this annex is essential for interoperability with GSM and 3GPP wireless systems. indication of success in implementing the AMR-WB codec. Annex E describes the recommended fi-ame structure for use with the different modes of operation for the AMR-WB algorithm. AMR-WB frames. Annex A describes comfo
45、rt noise aspects for use of the AMR-WB algorithm in source Annex B describes the source controlled rate operation for the AMR-WB algorithm. The Annex D describes the digital test sequences, which are a verification tool providing an Appendix I describes an example solution for error concealment of e
46、rroneous or lost For better usability, the ANSI-C code with the low-level description of all these functionalities have been grouped into a single Annex, Annex C. Should there be any discrepancy between the descriptions in any of the different parts of this Recommendation and the implementation of s
47、uch descriptions in Annex C, the descriptions in Annex C shall prevail. In clause 8 a specific reset procedure, called codec homing, is described. This is a useful feature for bringing the codec into a known initial state (e.g. for testing purposes). Clause 9 specifies the Voice Activity Detector (V
48、AD) used in this codec as well as in the source controlled rate operation (DTX) mpyyp$.p, y users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid
49、 ITU-T Recommendations is regularly published. 3 Definitions, symbols and abbreviations 3.1 Definitions This Recommendation defines the following terms: 3.1.1 adaptive codebook: The adaptive codebook contains excitation vectors that are adapted for every subfi-ame. The adaptive codebook is derived fi-om the long-term filter state. The lag value can be viewed as an index into the adaptive codebook. 3.1.2 algebraic codebook: A fixed codebook where algebraic code is used to populate the excitation vectors (innovation vectors). The excitation contains a small number of nonzero pulses wit
