ITU-T G 729 1-2006 G 729-based embedded variable bit-rate coder An 8-32 kbit s scalable wideband coder bitstream interoperable with G 729 (Study Group 16 Incorporated Amendment 1 1.pdf

1、I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o nITU-T G.729.1TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU(05/2006)SERIES G: TRANSMISSION SYSTEMS AND MEDIA,DIGITAL SYSTEMS AND NETWORKSDigital terminal equipments Coding of analogue signalsby methods other than PCMG.729-based embe

2、dded variable bit-rate coder:An 8-32 kbit/s scalable wideband coderbitstream interoperable with G.729ITU-T Recommendation G.729.1ITU-T G-SERIES RECOMMENDATIONSTRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKSINTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199GENERAL CHARACTERISTIC

3、S COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMSG.200G.299INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONESYSTEMS ON METALLIC LINESG.300G.399GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMSON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLICLINESG.4

4、00G.449COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499TRANSMISSION MEDIA CHARACTERISTICS G.600G.699DIGITAL TERMINAL EQUIPMENTS G.700G.799General G.700G.709Coding of analogue signals by pulse code modulation G.710G.719Coding of analogue signals by methods other than PCM G.720G.729Princip

5、al characteristics of primary multiplex equipment G.730G.739Principal characteristics of second order multiplex equipment G.740G.749Principal characteristics of higher order multiplex equipment G.750G.759Principal characteristics of transcoder and digital multiplication equipment G.760G.769Operation

6、s, administration and maintenance features of transmission equipment G.770G.779Principal characteristics of multiplexing equipment for the synchronous digital hierarchy G.780G.789Other terminal equipment G.790G.799DIGITAL NETWORKS G.800G.899DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999QUALITY

7、OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATEDASPECTSG.1000G.1999TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999PACKET OVER TRANSPORT ASPECTS G.8000G.8999ACCESS NETWORKS G.9000G.9999For further details, please refer to the list of ITU-T Recommenda

8、tions.ITU-T Rec. G.729.1 (05/2006) iITU-T Recommendation G.729.1G.729-based embedded variable bit-rate coder:An 8-32 kbit/s scalable wideband coder bitstream interoperable with G.729SummaryThis Recommendation describes an 8-32 kbit/s scalable wideband speech and audio codingalgorithm interoperable w

9、ith G.729, G.729A and G.729B.The output of the G.729EV coder has a bandwidth of 50-4000 Hz at 8 and 12 kbit/s and 50-7000 Hzfrom 14 to 32 kbit/s. At 8 kbit/s, G.729EV is fully interoperable with G.729, Annex A/G.729 andAnnex B/G.729. Hence, an efficient deployment in existing G.729-based VoIP infras

10、tructures isforeseen. The coder operates on 20 ms frames and has an algorithmic delay of 48.9375 ms. Bydefault, the encoder input and decoder output are sampled at 16 kHz.The encoder produces an embedded bitstream structured in 12 layers corresponding to 12 availablebit rates from 8 to 32 kbit/s. Th

11、e bitstream can be truncated at the decoder side or by any componentof the communication system to adjust “on the fly“ the bit rate to the desired value with no need foroutband signalling.The underlying algorithm is based on a three-stage coding structure: embedded Code-Excited LinearPrediction (CEL

12、P) coding of the lower band (50-4000 Hz), parametric coding of the higher band(4000-7000 Hz) by Time-Domain Bandwidth Extension (TDBWE), and enhancement of the fullband (50-7000 Hz) by a predictive transform coding technique referred to as Time-Domain AliasingCancellation (TDAC).Amendment 1 introduc

13、es the new Annex A containing the RTP payload format, capability identifiersand parameters for signalling of G.729.1 capabilities using H.245. Both format and capabilityparameters are fully compatible with the corresponding G.729.1 RTP definitions to allow seamlessinteroperability. Besides the new A

14、nnex, Amendment 1 to G.729.1 incorporates changes needed tocorrect defects in G.729.1 and provides new, more comprehensive test vectors.Amendment 2 introduces the new Annex B, which defines an alternative implementation of theG.729.1 algorithm using floating point arithmetic to be used for implement

15、ation on DSP hardwareoptimized for floating-point operations. The accompanying floating point C-code is fullyinteroperable with the fixed-point C-code.SourceITU-T Recommendation G.729.1 was approved on 29 May 2006 by ITU-T Study Group 16(2005-2008) under the ITU-T Recommendation A.8 procedure.This e

16、dition incorporates the modifications introduced by Amendment 1 approved on13 January 2007 and Amendment 2 approved on 13 February 2007.ii ITU-T Rec. G.729.1 (05/2006)FOREWORDThe International Telecommunication Union (ITU) is the United Nations specialized agency in the field oftelecommunications. T

17、he ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ ofITU. ITU-T is responsible for studying technical, operating and tariff questions and issuingRecommendations on them with a view to standardizing telecommunications on a worldwide basis.The World Telecommunication Standard

18、ization Assembly (WTSA), which meets every four years,establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations onthese topics.The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.In some areas of information techno

19、logy which fall within ITU-Ts purview, the necessary standards areprepared on a collaborative basis with ISO and IEC.NOTEIn this Recommendation, the expression “Administration“ is used for conciseness to indicate both atelecommunication administration and a recognized operating agency.Compliance wit

20、h this Recommendation is voluntary. However, the Recommendation may contain certainmandatory provisions (to ensure e.g., interoperability or applicability) and compliance with theRecommendation is achieved when all of these mandatory provisions are met. The words “shall“ or someother obligatory lang

21、uage such as “must“ and the negative equivalents are used to express requirements. Theuse of such words does not suggest that compliance with the Recommendation is required of any party.INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this Rec

22、ommendation mayinvolve 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 othersoutside of the Recommendation development process.As of the date of appro

23、val of this Recommendation, ITU had not received notice of intellectual property,protected by patents, which may be required to implement this Recommendation. However, implementorsare cautioned that this may not represent the latest information and are therefore strongly urged to consult theTSB pate

24、nt database.ITU 2007All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without theprior written permission of ITU.ITU-T Rec. G.729.1 (05/2006) iiiCONTENTSPage1 Scope. 12 References. 13 Abbreviations 24 Notations and conventions 35 General description of the

25、coder . 55.1 Encoder. 65.2 Decoder. 75.3 Frame erasure concealment (FEC) . 85.4 Coder modes. 95.5 Bit allocation to coder parameters and bitstream layer format. 105.6 Algorithmic delay. 115.7 Computational complexity and storage requirement 125.8 Coder description 126 Functional description of the e

26、ncoder. 126.1 QMF analysis filterbank, signal downscaling and spectral folding of thehigher band . 126.2 Pre-processing of lower band . 146.3 Narrowband embedded CELP encoder (Layers 1 and 2). 146.4 Pre-processing of the higher band 256.5 TDBWE encoder (Layer 3) 256.6 TDAC encoder (Layers 4 to 12) .

27、 307 Functional description of the decoder. 407.1 Narrowband embedded CELP decoder (Layers 1 and 2). 407.2 TDBWE decoder (Layer 3) 417.3 TDAC decoder (Layers 4 to 12). 497.4 Post-filtering of the lower band 577.5 Spectral folding of higher band, signal upscaling and QMF synthesisfilterbank. 597.6 Fr

28、ame erasure concealment 607.7 Bit-rate switching . 738 Description of the transmitted parameter indices . 759 Bit-exact description of the G.729EV coder. 789.1 Use of the simulation software . 789.2 Organization of the simulation software 79Annex A Packet format, capability identifiers and capabilit

29、y parameters 86A.1 References 86A.2 Packet structure for G.729.1 frames . 86A.3 Capability identifiers and parameters for use with ITU-T Rec. H.245 86iv ITU-T Rec. G.729.1 (05/2006)PageA.4 Interoperability with ITU-T Rec. G.729. 88Annex B Reference floating-point implementation for G.729.1 88B.1 Sco

30、pe 88B.2 References 88B.3 Overview 88B.4 Algorithmic description 88B.5 ANSI C Code 89ITU-T Rec. G.729.1 (05/2006) 1ITU-T Recommendation G.729.1G.729-based embedded variable bit-rate coder:An 8-32 kbit/s scalable wideband coder bitstream interoperable with G.7291 ScopeThis Recommendation contains the

31、 description of an algorithm extending ITU-T Rec. G.729 for thescalable coding of narrowband and wideband speech and audio signals at 8-32 kbit/s.This Recommendation is organized as follows. The references, abbreviations and notations usedthroughout this Recommendation are defined in clauses 2, 3 an

32、d 4, respectively. Clause 5 gives ageneral outline of the G.729EV algorithm. The G.729EV encoder and decoder principles arediscussed in clauses 6 and 7, respectively. The transmitted parameters are presented in clause 8.Clause 9 describes the software that defines this coder in 16-32 bits fixed-poin

33、t arithmetic.2 ReferencesThe following ITU-T Recommendations and other references contain provisions which, throughreference in this text, constitute provisions of this Recommendation. At the time of publication, theeditions indicated were valid. All Recommendations and other references are subject

34、to revision;users of this Recommendation are therefore encouraged to investigate the possibility of applying themost recent edition of the Recommendations and other references listed below. A list of thecurrently valid ITU-T Recommendations is regularly published. The reference to a document withint

35、his Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T Recommendation G.191 (2005), Software tools for speech and audio codingstandardization. ITU-T Recommendation G.192 (1996), A common digital parallel interface for speechstandardization activities. I

36、TU-T Recommendation G.729 (1996), Coding of speech at 8 kbit/s usingconjugate-structure algebraic-code-excited linear prediction (CS-ACELP). ITU-T Recommendation G.729 Annex A (1996), Reduced complexity 8 kbit/s CS-ACELPspeech codec. ITU-T Recommendation G.729 Annex B (1996), A silence compression s

37、cheme forG.729 optimized for terminals conforming to Recommendation V.70.2 ITU-T Rec. G.729.1 (05/2006)3 AbbreviationsThe acronyms used in this Recommendation are summarized in Table 1.Table 1/G.729.1 Glossary of acronymsAcronym DescriptionACELP Algebraic CELPBWE BandWidth ExtensionCELP Code-Excited

38、 Linear PredictionCNG Comfort Noise GeneratorDEMUX DEMUltipleXerDTX Discontinuous TransmissionFEC Frame Erasure ConcealmentFIR Finite Impulse ResponseFFT Fast Fourier TransformG.729EV G.729 Embedded Variable bit rateHB Higher BandHPF High Pass FilterIIR Infinite Impulse ResponseIP Internet ProtocolL

39、B Lower-BandLP Linear PredictionLPF Low Pass FilterLSB Least Significant BitLSF Line Spectrum FrequencyLSP Line Spectrum PairLTP Long-Term PredictionMDCT Modified Discrete Cosine TransformMSB Most Significant BitMUX MUltipleXerPCM Pulse Code ModulationQMF Quadrature Mirror FilterbankSID Silence Inse

40、rtion DescriptorTDAC Time-Domain Aliasing CancellationTDBWE Time-Domain BandWidth ExtensionVoIP Voice over IPVQ Vector QuantizationWB WidebandWMOPS Weighted Million Operations Per SecondITU-T Rec. G.729.1 (05/2006) 34 Notations and conventionsTo be consistent with the text of ITU-T Rec. G.729, the 2

41、0 ms frames used by G.729EV will bereferred to as superframes, whereas the 10 ms frames and the 5 ms subframes involved in the CELPprocessing will be respectively called frames and subframes.Throughout this Recommendation, the G.729 notations are reused. The notational conventions aredetailed below:

42、 Codebooks are denoted by calligraphic characters (e.g., ). Time-domain signals are denoted by their symbol and a sample index between parenthesis,e.g., s(n). The variable n is used as sample index. Frequency-domain transforms are denoted by converting the related time-domain signal tocapital letter

43、s, e.g., S(k) is the transform of s(n). The variable k is used as coefficient index. Superscript indices between parentheses (e.g., g(m) are used to indicate time-dependency ofvariables. The variable m refers, depending on the context, to either a frame or subframeindex, and the variable n to a samp

44、le index. Recursion indices are identified by a superscript between square brackets (e.g., Ek). Subscripts indices identify a particular element in a coefficient array. The symbol identifies a quantized version of a parameter (e.g., cg). Parameter ranges are given between square brackets, and includ

45、e the boundaries(e.g., 0.6, 0.9). The function int() denotes truncation to its integer value. The function ()even returns 1 if the argument is an even integer number and 0 otherwise. The function ()round denotes the rounding to the nearest integer. The floating-point numbers used are rounded version

46、s of the values used in the 16-bitfixed-point ANSI C implementation.4 ITU-T Rec. G.729.1 (05/2006)Table 2 lists the most relevant symbols used throughout this Recommendation.Table 2/G.729.1 Glossary of most relevant symbolsType Name DescriptionFilters 1/(z) Quantized LP synthesis filterHh1(z) Lower-

47、band high-pass filterHp(z) Long-term postfilterHf(z) Short-term postfilterHt(z) Tilt-compensation filterHh2(z) Higher-band low-pass filterH1(z) QMF low pass analysis filterH2(z) QMF high pass analysis filterG1(z) QMF low pass synthesis filterG2(z) QMF high pass synthesis filterP(z) Pre-filter for fi

48、xed codebook in G.729W(z) Weighting filter in embedded CELP encoderWLB(z) Lower-band difference weighting filterSignals c(n) 12 kbit/s layer fixed-codebook codevector)(nsWB Wideband input signal)(nsqmfLB QMF low pass analysis filter output signal after decimation)()( nsnsLBPre-processed lower band s

49、ignal)(ndLB Lower-band difference signal between )(ns and )(nsenh)(nd wLB Lower-band difference weighting filter output signal)(ns foldHB QMF analysis filter output signal after decimation andspectral folding)(nsHB Pre-processed higher band signal)(ns 8 kbit/s CELP decoded signal)(nsenh 12 kbit/s CELP decoded signal)(nsLB Lower-band decoded signal before postfiltering)(ns postLB Postfiltered lower-band decoder signal)(nshpfLB High-pass filtered postfiltered lower band reconstructedsignal)(nsqmfLB Decoded lower-ban