1、 ETSI TS 126 441 V15.0.0 (2018-07) Universal Mobile Telecommunications System (UMTS); LTE; Codec for Enhanced Voice Services (EVS); General overview (3GPP TS 26.441 version 15.0.0 Release 15) TECHNICAL SPECIFICATION ETSI ETSI TS 126 441 V15.0.0 (2018-07)13GPP TS 26.441 version 15.0.0 Release 15Refer
2、ence RTS/TSGS-0426441vf00 Keywords LTE,UMTS ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice The
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9、rsion 15.0.0 Release 15Intellectual Property Rights Essential patents IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
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15、rm.asp. Modal verbs terminology In the present document “shall“, “shall not“, “should“, “should not“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions). “must“ and “mus
16、t not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TS 126 441 V15.0.0 (2018-07)33GPP TS 26.441 version 15.0.0 Release 15Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Abbreviations .
17、 5g34 General . 6g35 Transcoding functions 8g36 ANSI C-code 9g37 Test vectors 9g38 Discontinuous transmission (DTX) 10g39 Voice activity detection 10g310 Comfort noise insertion 10g311 Error concealment of lost frames . 11g312 Frame structure . 11g313 RTP Payload Format 11g314 Jitter Buffer Manageme
18、nt . 11g315 Performance characterization . 11g3Annex A (informative): Change history . 12g3History 13g3ETSI ETSI TS 126 441 V15.0.0 (2018-07)43GPP TS 26.441 version 15.0.0 Release 15Foreword This Technical Specification has been produced by the 3rdGeneration Partnership Project (3GPP). The contents
19、of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: V
20、ersion x.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the
21、 third digit is incremented when editorial only changes have been incorporated in the document. ETSI ETSI TS 126 441 V15.0.0 (2018-07)53GPP TS 26.441 version 15.0.0 Release 151 Scope The present document is an introduction to the audio processing parts of the Enhanced Voice Services coder. A general
22、 overview of the audio processing functions is given, with reference to the documents where each function is specified in detail. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. - References are either spec
23、ific (identified by date of publication, edition number, version number, etc.) or non-specific. - For a specific reference, subsequent revisions do not apply. - For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-s
24、pecific reference implicitly refers to the latest version of that document in the same Release as the present document. 1 3GPP TR 21.905: “Vocabulary for 3GPP Specifications“. 2 3GPP TS 26.445: “Codec for Enhanced Voice Services (EVS); Detailed Algorithmic Description“. 3 3GPP TS 26.442: “Codec for
25、Enhanced Voice Services (EVS); ANSI C code (fixed-point)“. 4 3GPP TS 26.443: “Codec for Enhanced Voice Services (EVS); ANSI C code (floating point)“. 5 3GPP TS 26.444: “Codec for Enhanced Voice Services (EVS); Test Sequences“. 6 3GPP TS 26.446: “Codec for Enhanced Voice Services (EVS); AMR-WB Backwa
26、rd Compatible Functions“. 7 3GPP TS 26.447: “Codec for Enhanced Voice Services (EVS); Error Concealment of Lost Packets“. 8 3GPP TS 26.448: “Codec for Enhanced Voice Services (EVS); Jitter Buffer Management“. 9 3GPP TS 26.449: “Codec for Enhanced Voice Services (EVS); Comfort Noise Generation (CNG)
27、Aspects“. 10 3GPP TS 26.450: “Codec for Enhanced Voice Services (EVS); Discontinuous Transmission (DTX)“. 11 3GPP TS 26.451: “Codec for Enhanced Voice Services (EVS); Voice Activity Detection (VAD)“. 12 3GPP TS 26.114: “IP Multimedia Subsystem (IMS); Multimedia telephony; Media handling and interact
28、ion“. 13 3GPP TS 26.131: “Terminal acoustic characteristics for telephony; Requirements“. 14 3GPP TR 26.952: “Codec for Enhanced Voice Services (EVS); Performance Characterization“. 3 Abbreviations For the purposes of the present document, the abbreviations given in TR 21.905 1 and the following app
29、ly. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905 1. ACELP Algebraic Code-Excited Linear Prediction AMR-WB Adaptive Multi Rate Wideband (codec) CNG Comfort Noise Generator DTX Discontinuous Transmission ETSI ETSI T
30、S 126 441 V15.0.0 (2018-07)63GPP TS 26.441 version 15.0.0 Release 15EVS Enhanced Voice Services FB Fullband FEC Frame Erasure Concealment IP Internet Protocol JBM Jitter Buffer Management MSB Most Significant Bit MTSI Multimedia Telephony Service for IMS NB Narrowband PS Packet SwitchedPSTN Public S
31、witched Telephone Network SAD Sound Activity Detection SC-VBR Source Controlled - Variable Bit Rate SID Silence Insertion Descriptor SWB Super Wideband VAD Voice Activity Detection WB Wideband WMOPS Weighted Millions of Operations Per Second 4 General The Enhanced Voice Services coder consists of th
32、e multi-rate audio coder optimized for operation with voice and music/mixed content signals, a source controlled rate scheme including a voice/sound activity detector and a comfort noise generation system, and an error concealment mechanism to combat the effects of transmission errors and lost packe
33、ts. Jitter buffer management is also provided. The EVS coder also provides enhanced interoperation with AMR-WB over all nine source bit rates from 6,6 kbit/s to 23,85 kbit/s. The EVS speech coder is capable of switching its bit-rate every 20 ms speech frame upon command. A reference configuration wh
34、ere the various speech processing functions are identified is given in Figure 1. In this figure, the relevant specifications for each function are also indicated. In Figures 1 - evaluation of the background acoustic noise on the TX side, in order to transmit characteristic parameters to the RX side;
35、 - generation of comfort noise on the RX side during periods when no normal speech frames are received. The transmission of comfort noise information to the RX side is achieved by means of a Silence Descriptor (SID) frame, which is sent at regular intervals. - a Source-Controlled Variable Bit Rate o
36、perational mode (SC-VBR) operating at 5,9 kbit/s is also provided to reduce the operational bit rate still further for NB and WB speech services. 9 Voice activity detection The Enhanced Voice Services codec VAD function is described in 2 - the noise parameter encoding (SID frames) and decoding, and
37、- the generation of comfort noise in the receiver. The comfort noise processes and the algorithm for updating the noise parameters during speech pauses are defined in detail in 2, and the corresponding C-code is defined in 3 & 4. ETSI ETSI TS 126 441 V15.0.0 (2018-07)113GPP TS 26.441 version 15.0.0
38、Release 1511 Error concealment of lost frames The EVS coder error concealment of erroneous or lost frames is described in 2 & 7. Frames may be erroneous due to transmission errors or frames may be lost or delayed due to packet loss in a transport network. The methods described in 2 & 7 may be used a
39、s a basis for error concealment. In order to mask the effect of isolated erroneous/lost frames, the decoder shall be informed about erroneous/lost frames and the error concealment actions shall be initiated, whereby a set of predicted parameters are used in the speech synthesis. Insertion of speech
40、signal independent silence frames is not allowed. 12 Frame structure The EVS coder frame structure is described in 2. 13 RTP Payload Format The EVS coder RTP Payload Format for media handling and interaction is described in 2. 14 Jitter Buffer Management The EVS coder Jitter Buffer Management is des
41、cribed in 8. 15 Performance characterization The EVS coder performance characterization is described in 14. ETSI ETSI TS 126 441 V15.0.0 (2018-07)123GPP TS 26.441 version 15.0.0 Release 15Annex A (informative): Change history Change history Date TSG # TSG Doc. CR Rev Subject/Comment Old New 06-2014
42、64 SP-140208 Presented to TSG SA#64 for information 1.0.0 09-2014 65 SP-140457 Presented to TSG SA#65 for approval 1.0.0 2.0.0 09-2014 65 Approved a TSG SA#65 2.0.0 12.0.0 12-2014 66 SP-140723 0001 Typographical correction 12.0.0 12.1.0 12-2015 70 Version for Release 13 12.1.0 13.0.0 Change history Date Meeting TDoc CR Rev Cat Subject/Comment New version 2017-03 75 Version for Release 14 14.0.0 2018-06 80 Version for Release 15 15.0.0 ETSI ETSI TS 126 441 V15.0.0 (2018-07)133GPP TS 26.441 version 15.0.0 Release 15History Document history V15.0.0 July 2018 Publication
