1、 International Telecommunication Union ITU-T G.729TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (06/2012) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital terminal equipments Coding of voice and audio signals Coding of speech at 8 kbit/s using conjugate-structure alge
2、braic-code-excited linear prediction (CS-ACELP) Recommendation ITU-T G.729 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTE
3、MS G.200G.299 INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND
4、LINE TELEPHONY G.450G.499 TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 General G.700G.709 Coding of voice and audio signals G.710G.729Principal characteristics of primary multiplex equipment G.730G.739 Principal characteristics of second or
5、der multiplex equipment G.740G.749 Principal characteristics of higher order multiplex equipment G.750G.759 Principal characteristics of transcoder and digital multiplication equipment G.760G.769 Operations, administration and maintenance features of transmission equipment G.770G.779 Principal chara
6、cteristics of multiplexing equipment for the synchronous digital hierarchy G.780G.789 Other terminal equipment G.790G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSM
7、ISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.729 (06/2012) i Recommendation ITU-T G.729 Coding of
8、 speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear prediction (CS-ACELP) Summary Recommendation ITU-T G.729 contains the description of an algorithm for the coding of speech signals using conjugate-structure algebraic-code-excited linear prediction (CS-ACELP). In its basic m
9、ode, the ITU-T G.729 coder consists of a mono-rate speech coder at 8 kbit/s using fixed-point arithmetic operations. Annexes A, B, and D to J extend its functionalities. Annex A provides a reduced-complexity version at the basic coding rate of 8 kbit/s. Annex B defines source-controlled rate operati
10、on for use with ITU-T G.729 or Annex A. Annexes D, E and H provide multi-rate operation and specify rate-switching mechanisms. Annex D also provides lower bit-rate extension at 6.4 kbit/s and Annex E also provides higher bit-rate extension at 11.8 kbit/s. Annex H provides bit-rate extensions at both
11、 6.4 kbit/s and 11.8 kbit/s. Therefore, Annexes D, E and H do not implement the discontinuous transmission mode of Annex B. For this functionality, further annexes were developed. Annexes F and G use the basic algorithms of Annex B to provide discontinuous transmission (DTX) functionality for Annexe
12、s D and E. Annex I provides DTX functionality for Annex H and describes the integration of the main body of this Recommendation with Annexes B, D and E. Annex J makes reference to the ITU-T G.729 extension for the 8-32 kbit/s scalable wideband speech and audio coding algorithm defined in ITU-T G.729
13、.1, which is interoperable with this Recommendation and its Annexes A and B. As in the main body of this Recommendation, Annexes A, B, and D to J use fixed-point arithmetic. Alternative implementations based on floating-point arithmetic operations are provided in Annex C for ITU-T G.729 and Annex A,
14、 as well as in Annex C+ for Annex I. This information is summarized in the Table below. Annexes Functionality Low complexity X X Fixed-point X X X X X X X X X X Floating-point X X 8 kbit/s X X X X X X X X X X X X 6.4 kbit/s X X X X X 11.8 kbit/s X X X X X DTX X X X X X Embedded variable bit rate, wi
15、deband X Appendix I deals with external synchronous reset capability in systems using external silence compression in conjunction with the speech coding algorithm in the main body of this Recommendation (fixed-point) or in its Annex A (low complexity, fixed-point) and Annex C (floating-point). Since
16、 the voice activity detection (VAD) algorithm in Annex B was optimized for transmission over connection-oriented circuits, Appendices II and III deal with optimization of the VAD in Annex B when it is used for packet circuits such as VoIP applications. Appendix IV, introduced in this revision of ITU
17、-T G.729 describes the use of ITU-T G.720.1 Annex A as a VAD for use with Annex B DTX/CNG. It provides better flexibility in terms of ii Rec. ITU-T G.729 (06/2012) compromise between bandwidth saving and audio quality. Bandwidth-saving mode provides the best performance in terms of silence compressi
18、on while maintaining the subjective quality at a level comparable to both Appendix II and III. Moreover, Appendix IV offers better robustness to a wide variety of background noise types, including music. The target for Appendix IV is new IP multimedia services, and IP telephony and videoconferencing
19、 (both for enterprise corporate networks and for mass market); these are some of the most important services for which it has been optimized. Target devices include IP phones or other VoIP handsets, home gateways, IPBX, and media gateways. This Recommendation also corrects the defects identified in
20、the Implementors Guide for ITU-T G.729 (2009/11), namely a discrepancy that was found between equation 40 (in clause 3.7.1) and the C-code. Reference ANSI C source code and test vectors are provided as an integral part of this Recommendation and its annexes. Appendices II, III and IV are also associ
21、ated with C source code and test vectors. No source code is associated with Appendix I. The reference C source code and test vectors for the CS-ACELP algorithms described in the main body, and applicable annexes, and appendices are available as electronic attachments to this Recommendation. History
22、Edition Recommendation Approval Study Group 1.0 ITU-T G.729 1996-03-20 15 1.1 ITU-T G.729 Annex B 1996-10-18 15 1.2 ITU-T G.729 Annex A 1996-11-11 16 1.3 ITU-T G.729 Annex B (1996) Cor. 1 1998-02-06 16 1.4 ITU-T G.729 Annex C 1998-09-25 16 1.5 ITU-T G.729 Annex D 1998-09-25 16 1.6 ITU-T G.729 Annex
23、E 1998-09-25 16 1.7 ITU-T G.729 Annex B (1996) Cor. 2 2000-02-17 16 1.8 ITU-T G.729 Annex C+ 2000-02-17 16 1.9 ITU-T G.729 Annex D (1998) Cor. 1 2000-02-17 16 1.10 ITU-T G.729 Annex E (1998) Cor. 1 2000-02-17 16 1.11 ITU-T G.729 Annex F 2000-02-17 16 1.12 ITU-T G.729 Annex G 2000-02-17 16 1.13 ITU-T
24、 G.729 Annex H 2000-02-17 16 1.14 ITU-T G.729 Annex I 2000-02-17 16 1.15 ITU-T G.729 Annex B (1996) Cor. 3 2001-03-01 16 1.16 ITU-T G.729 Annex C+ (2000) Cor. 1 2001-03-01 16 1.17 ITU-T G.729 Annex F (2000) Cor. 1 2001-03-01 16 1.18 ITU-T G.729 Annex G (2000) Cor. 1 2001-03-01 16 1.19 ITU-T G.729 An
25、nex I (2000) Cor. 1 2001-03-01 16 1.20 ITU-T G.729 App. I 2001-06-08 16 1.21 ITU-T G.729 App. II 2005-08-05 16 1.22 ITU-T G.729 App. III 2005-08-05 16 1.23 ITU-T G.729 Annex J 2006-05-29 16 2.0 ITU-T G.729 2007-01-13 16 3.0 ITU-T G.729 2012-06-29 16 Rec. ITU-T G.729 (06/2012) iii FOREWORD The Intern
26、ational Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, ope
27、rating and tariff questions 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,
28、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 information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In
29、 this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g.
30、, interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not sug
31、gest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evi
32、dence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may
33、be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2013 All rights reserved. No part of this publication may be r
34、eproduced, by any means whatsoever, without the prior written permission of ITU. iv Rec. ITU-T G.729 (06/2012) Table of Contents Page 1 Scope 1 2 General description of the coder . 1 2.1 Encoder . 2 2.2 Decoder . 3 2.3 Delay . 4 2.4 Speech coder description 4 2.5 Notational conventions . 4 3 Functio
35、nal description of the encoder . 7 3.1 Preprocessing 7 3.2 Linear prediction analysis and quantization . 7 3.3 Perceptual weighting 15 3.4 Open-loop pitch analysis 16 3.5 Computation of the impulse response 17 3.6 Computation of the target signal 17 3.7 Adaptive-codebook search . 18 3.8 Fixed codebo
36、ok Structure and search 20 3.9 Quantization of the gains 23 3.10 Memory update . 24 4 Functional description of the decoder . 25 4.1 Parameter decoding procedure . 25 4.2 Post-processing . 28 4.3 Encoder and decoder initialization . 30 4.4 Concealment of frame erasures 31 5 Bit-exact description of
37、the CS-ACELP coder . 32 5.1 Use of the simulation software . 32 5.2 Organization of the simulation software 33 6 References. 36 Annex A Reduced complexity 8 kbit/s CS-ACELP speech codec . 37 A.1 Introduction 37 A.2 General description of the codec 37 A.3 Functional description of the encoder 38 A.4
38、Functional description of the decoder 42 A.5 Bit-exact description of the reduced complexity CS-ACELP codec 44 Annex B A silence compression scheme for ITU-T G.729 optimized for terminals conforming to ITU-T V.70 . 45 B.1 Introduction 45 B.2 General description of the VAD/DTX/CNG algorithms 46 B.3 D
39、etailed description of the VAD algorithm . 46 Rec. ITU-T G.729 (06/2012) v Page B.4 Detailed description of the DTX/CNG algorithms . 54 B.5 Bit-exact description of the silence compression scheme 60 Annex C Reference floating-point implementation for ITU-T G.729 CS-ACELP 8 kbit/s speech coding 61 C.
40、1 Scope 61 C.2 Normative references 61 C.3 Overview 61 C.4 Algorithmic description 61 C.5 ANSI C code . 61 Annex C+ Reference floating-point implementation for integrating ITU-T G.729 CS-ACELP speech coding main body with Annexes B, D and E 64 C+.1 Scope 64 C+.2 Normative references 64 C+.3 Overview
41、 64 C+.4 New functionality . 64 C+.5 Algorithm description . 65 C+.6 Description of C source code . 70 Annex D +CS-ACELP speech coding algorithm at 6.4 kbit/s 73 D.1 Scope 73 D.2 Normative references 73 D.3 General coder description for the 6.4 kbit/s extension . 73 D.4 Bit allocation 74 D.5 Functio
42、nal description of the encoder 74 D.6 Functional description of decoder 75 D.7 ANSI C code . 75 Annex E CS-ACELP speech coding algorithm at 11.8 kbit/s. 78 E.1 Introduction 78 E.2 General description of the speech codec 78 E.3 Functional description of the encoder 80 E.4 Functional description of th
43、e decoder 89 E.5 Bit-exact description of the CS-ACELP coder . 96 Annex F Reference implementation of ITU-T G.729 Annex B DTX functionality for Annex D 99 F.1 Scope 99 F.2 Normative references 99 F.3 Overview 99 F.4 New functionality . 99 F.5 Algorithm description . 100 F.6 Description of C source c
44、ode . 100 vi Rec. ITU-T G.729 (06/2012) Page Annex G Reference implementation of Annex B DTX functionality for Annex E 103 G.1 Scope 103 G.2 Normative references 103 G.3 Overview 103 G.4 New functionality . 103 G.5 Algorithm description . 104 G.6 Description of C source code . 108 Annex H Reference
45、implementation of switching procedure between Annexes D and E . 112 H.1 Scope 112 H.2 Normative references 112 H.3 Overview 112 H.4 Algorithm description . 112 H.5 Description of C source code . 113 Annex I Reference fixed-point implementation for integrating ITU-T G.729 CS-ACELP speech coding main
46、body with Annexes B, D and E 116 I.1 Scope 116 I.2 Normative references 116 I.3 Overview 116 I.4 New functionality . 116 I.5 Algorithm description . 117 I.6 Description of C source code . 121 Annex J An embedded variable bit-rate extension to ITU-T G.729: An interoperable 8-32 kbit/s scalable wideba
47、nd extension to ITU-T G.729 125 Appendix I External synchronous reset performance for ITU-T G.729 codecs in systems using external VAD/DTX/CNG 126 I.1 Introduction 126 I.2 Experimental design . 126 I.3 Performance observations 127 I.4 Conclusion 127 Appendix II ITU-T G.729 Annex B enhancements in vo
48、ice-over-IP applications Option 1 128 II.1 Scope 128 II.2 Abbreviations and acronyms 128 II.3 Introduction 128 II.4 Identified problems of ITU-T G.729B in VoIP applications . 128 II.5 Experimental design . 129 II.6 Electronic attachments 133 Rec. ITU-T G.729 (06/2012) vii Page Appendix III Annex B e
49、nhancements in voice-over-IP applications Option 2 . 134 III.1 Scope 134 III.2 Solutions for the reported issues with Annex B . 134 III.3 Examples for the solutions of reported issues with Annex B . 134 III.4 Electronic attachments 137 Appendix IV Enhanced Voice Activity Detector . 138 IV.1 Scope 138 IV.2 References 138 IV.3 Definitions 138 IV.4 Abbreviations and acronyms 139 IV.5 General description of enhanced VAD algorithm 139 IV.6 De
