1、 International Telecommunication Union ITU-T G.722.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Corrigendum 1(06/2008) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital terminal equipments Coding of analogue signals by methods other than PCM Low-complexity coding at
2、24 and 32 kbit/s for hands-free operation in systems with low frame lossCorrigendum 1: Correction of Annex B source code ITU-T Recommendation G.722.1 (2005) Corrigendum 1 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS A
3、ND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS 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 SATELL
4、ITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND 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
5、characteristics of primary multiplex equipment G.730G.739 Principal characteristics of second order 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 Operatio
6、ns, administration and maintenance features of transmission equipment G.770G.779 Principal characteristics 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 MU
7、LTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION 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
8、list of ITU-T Recommendations. ITU-T Rec. G.722.1 (2005)/Cor.1 (06/2008) i ITU-T Recommendation G.722.1 Low-complexity coding at 24 and 32 kbit/s for hands-free operation in systems with low frame loss Corrigendum 1 Correction of Annex B source code Summary This corrigendum corrects changes necessar
9、y to the existing C code (Release 2.0) that is supplied with Annex B of ITU-T Recommendation G.722.1. No changes are made to the textual part of the Recommendation. For convenience of users, this corrigendum has been integrated into the base text of the Recommendation, changing for consistency the d
10、esignation of the C code to Release 2.1. For access to the code in compilable form, please see http:/www.itu.int/rec/T-REC-G.722.1-200505-I. History Edition Recommendation Approval Study Group 1.0 ITU-T G.722.1 1999-09-30 16 1.1 ITU-T G.722.1 Annex A 2000-02-17 16 1.2 ITU-T G.722.1 (1999) Cor. 1 200
11、0-11-17 16 1.3 ITU-T G.722.1 Annex B 2000-11-17 16 2.0 ITU-T G.722.1 2005-05-14 16 2.1 ITU-T G.722.1 (2005) Cor. 1 2008-06-13 16 ii ITU-T Rec. G.722.1 (2005)/Cor.1 (06/2008) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunic
12、ations, 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, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunicat
13、ions 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 Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure
14、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 this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommun
15、ication administration and a recognized operating agency. 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 ma
16、ndatory 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 suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draw
17、s 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 evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or
18、 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 be required to implement this Recommendation. However, implementers are cautioned that this may not represen
19、t the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2010 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. G.722.1 (2005)/C
20、or.1 (06/2008) 1 ITU-T Recommendation G.722.1 Low-complexity coding at 24 and 32 kbit/s for hands-free operation in systems with low frame loss Corrigendum 1 Correction of Annex B source code 1 Correction to floating-point C source code of G.722.1 Annex B In the floating-point C source code of G.722
21、.1 Annex B, one file is changed: decoder.c These changes correct two problems: a) The noise fill energy was 26.8 dB too weak on the floating-point decoder, compared to the fixed-point source code. This has been corrected by defining a constant NOISE_SCALE_FACTOR, with the value of 22.0, and using th
22、is to scale the background noise. b) There was potential for an array overflow in certain circumstances. This has been corrected by bounding the index array. 1.1 Changes to decoder.c The changes to decoder.c are shown below. Comparing files decoder.c.old and DECODER.C * decoder.c.old 54: 55: #define
23、 GET_NEXT_BIT * DECODER.C 54: 55: #define NOISE_SCALE_FACTOR 22.0F 56: 57: #define GET_NEXT_BIT * * decoder.c.old 541: n+; 542: if (fabs(*decoder_mlt_ptr) 2.0*standard_deviation) 543: n += 3; * DECODER.C 543: n+; 544: if (fabs(*decoder_mlt_ptr) 44.0F*standard_deviation) 545: n += 3; * * decoder.c.ol
24、d 547: 548: temp1 = noise_fill_factor_cat5n; * DECODER.C 549: 550: if(n19)n=19; 551: temp1 = noise_fill_factor_cat5n; * * decoder.c.old 2 ITU-T Rec. G.722.1 (2005)/Cor.1 (06/2008) 562: if (random_word 563: *decoder_mlt_ptr = temp1; 564: random_word = 1; * DECODER.C 565: if (random_word 566: *decoder
25、_mlt_ptr = temp1*NOISE_SCALE_FACTOR; 567: random_word = 1; * * decoder.c.old 572: if (random_word 573: *decoder_mlt_ptr = temp1; 574: random_word = 1; * DECODER.C 575: if (random_word 576: *decoder_mlt_ptr = temp1*NOISE_SCALE_FACTOR; 577: random_word = 1; * * decoder.c.old 604: if (random_word 605:
26、*decoder_mlt_ptr = temp1; 606: random_word = 1; * DECODER.C 607: if (random_word 608: *decoder_mlt_ptr = temp1*NOISE_SCALE_FACTOR; 609: random_word = 1; * * decoder.c.old 614: if (random_word 615: *decoder_mlt_ptr = temp1; 616: random_word = 1; * DECODER.C 617: if (random_word 618: *decoder_mlt_ptr
27、= temp1*NOISE_SCALE_FACTOR ; 619: random_word = 1; * * decoder.c.old 634: if (random_word 635: *decoder_mlt_ptr+ = temp1; 636: random_word = 1; * DECODER.C 637: if (random_word 638: *decoder_mlt_ptr+ = temp1*NOISE_SCALE_FACTOR; 639: random_word = 1; * * decoder.c.old 641: if (random_word 642: *decod
28、er_mlt_ptr+ = temp1; 643: random_word = 1; * DECODER.C 644: if (random_word 645: *decoder_mlt_ptr+ = temp1*NOISE_SCALE_FACTOR; 646: random_word = 1; * Printed in Switzerland Geneva, 2010 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series B Available Series C Available
29、Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I I
30、ntegrated services digital network Series J Cable networks and transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M Telecommunication
31、 management, including TMN and network maintenance Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Telephone transmission quality, telephone installations, local line networks Series Q Switching and sign
32、alling Series R Telegraph transmission Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series W Available Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
