1、 ETSI TS 1Universal Mobile TelCodec for EnhJitter (3GPP TS 26.4TECHNICAL SPECIFICATION126 448 V13.0.0 (2016elecommunications System (LTE; n anced Voice Services (EVS)er buffer management .448 version 13.0.0 Release 1316-01) (UMTS); S); 13) ETSI ETSI TS 126 448 V13.0.0 (2016-01)13GPP TS 26.448 versio
2、n 13.0.0 Release 13Reference RTS/TSGS-0426448vd00 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
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8、registered for the benefit of its Members. 3GPPTM and LTE are Trade Marks of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. GSM and the GSM logo are Trade Marks registered and owned by the GSM Association. ETSI ETSI TS 126 448 V13.0.0 (2016-01)23GPP TS 26.448
9、 version 13.0.0 Release 13Intellectual Property Rights IPRs essential or potentially essential to the present document 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 in ETSI SR 000 3
10、14: “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (https:/ipr.etsi.org/). Pursuant to the ETSI IPR Policy, no investigat
11、ion, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This Technical Specificati
12、on (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP). The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables. T
13、he cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under http:/webapp.etsi.org/key/queryform.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
14、described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TS 126 448 V13.0.0 (2016-01)33GPP TS 26.448 version 13.0.0 Release 13Contents Intellectual Pro
15、perty Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Definitions, symbols and abbreviations . 5g33.1 Definitions 5g33.2 Symbols 5g33.3 Abbreviations . 6g33.4 Mathematical Expressions 6g34 General . 6g34.1 Introduction 6g34.2 Packet-based communications
16、7g34.3 EVS Receiver architecture overview 7g35 Jitter Buffer Management . 8g35.1 Overview 8g35.2 Depacketization of RTP packets (informative) 8g35.3 Network Jitter Analysis and Delay Estimation . 9g35.3.1 General 9g35.3.2 Long-term Jitter 10g35.3.3 Short-term jitter 10g35.3.4 Target Playout Delay 10
17、g35.3.5 Playout Delay Estimation . 11g35.4 Adaptation Control Logic . 12g35.4.1 Control Logic 12g35.4.2 Frame-based adaptation 12g35.4.2.1 General 12g35.4.2.2 Insertion of Concealed Frames 12g35.4.2.3 Frame Dropping 13g35.4.2.4 Comfort Noise Insertion in DTX 13g35.4.2.5 Comfort Noise Deletion in DTX
18、 . 13g35.4.3 Signal-based adaptation 13g35.4.3.1 General 13g35.4.3.2 Time-shrinking 14g35.4.3.3 Time-stretching . 15g35.4.3.4 Energy Estimation . 16g35.4.3.5 Similarity Measurement 16g35.4.3.6 Quality Control . 17g35.4.3.7 Overlap-add . 17g35.5 Receiver Output Buffer 18g35.6 De-Jitter Buffer 18g36 D
19、ecoder interaction 19g36.1 General . 19g36.2 Decoder Requirements . 19g36.3 Partial Redundancy. 19g36.3.1 Computation of the Partial Redundancy Offset 20g36.3.2 Computation of a frame erasure rate indicator to control the frequency of the Partial Redundancy transmission 21g3Annex A (informative): Ch
20、ange history . 22g3History 23 ETSI ETSI TS 126 448 V13.0.0 (2016-01)43GPP TS 26.448 version 13.0.0 Release 13Foreword This Technical Specification has been produced by the 3rdGeneration Partnership Project (3GPP). The contents of the present document are subject to continuing work within the TSG and
21、 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: Version x.y.z where: x the first digit: 1 presented to TSG for information
22、; 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 third digit is incremented when editorial only changes have been incorpo
23、rated in the document. ETSI ETSI TS 126 448 V13.0.0 (2016-01)53GPP TS 26.448 version 13.0.0 Release 131 Scope The present document defines the Jitter Buffer Management solution for the Codec for Enhanced Voice Services (EVS). 2 References The following documents contain provisions which, through ref
24、erence in this text, constitute provisions of the present document. - References are either specific (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 ve
25、rsion applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific 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
26、 Enhanced Voice Services (EVS); Detailed Algorithmic Description“. 3 3GPP TS 26.114: “IP Multimedia Subsystem (IMS); Multimedia telephony; Media handling and interaction“. 4 3GPP TS 26.071: “Mandatory speech CODEC speech processing functions; AMR speech Codec; General description“. 5 3GPP TS 26.171:
27、 “Speech codec speech processing functions; Adaptive Multi-Rate - Wideband (AMR-WB) speech codec; General description“. 6 3GPP TS 26.442: “Codec for Enhanced Voice Services (EVS); ANSI C code (fixed-point)“. 7 3GPP TS 26.443: “Codec for Enhanced Voice Services (EVS); ANSI C code (floating-point)“. 8
28、 3GPP TS 26.131: “Terminal acoustic characteristics for telephony; Requirements“. 9 IETF RFC 4867 (2007): “RTP Payload Format and File Storage Format for the Adaptive Multi-Rate (AMR) and Adaptive Multi-Rate Wideband (AMR-WB) Audio Codecs“, J. Sjoberg, M. Westerlund, A. Lakaniemi and Q. Xie. 3 Defin
29、itions, symbols and abbreviations 3.1 Definitions For the purposes of the present document, the terms and definitions given in TR 21.905 1 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 1. 3.2 Symbols For th
30、e purposes of the present document, the following symbols apply: Time signal and time index n in context x, e.g. x can be inp, out, HP, pre, etc. Frame length / size of module x Energy values in context of x ()nsxxLxEETSI ETSI TS 126 448 V13.0.0 (2016-01)63GPP TS 26.448 version 13.0.0 Release 13Corr
31、elation function in context x 3.3 Abbreviations For the purposes of the present document, the abbreviations given in TR 21.905 1 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905 1. AMR Adaptiv
32、e Multi Rate (codec) AMR-WB Adaptive Multi Rate Wideband (codec) CNG Comfort Noise Generator DTX Discontinuous Transmission EVS Enhanced Voice Services FB Fullband FIFO First In, First Out IP Internet ProtocolJBM Jitter Buffer Management MTSI Multimedia Telephony Service for IMS NB Narrowband PCM Pu
33、lse Code Modulation PLC Packet Loss Concealment RTP Real Time Transport Protocol SID Silence Insertion Descriptor SOLA Synchronized overlap-add SWB Super Wideband TSM Time Scale Modification VAD Voice Activity Detection WB Wideband 3.4 Mathematical Expressions For the purposes of the present documen
34、t, the following conventions apply to mathematical expressions: indicates the smallest integer greater than or equal to x: , and indicates the largest integer less than or equal to x: , and min(x0,xN1) indicates the minimum of x0, xN1, N being the number of components max(x0,xN1) indicates the maxim
35、um of x0, , xN1indicates summation 4 General 4.1 Introduction The present document defines the Jitter Buffer Management solution for the Codec for Enhanced Voice Services (EVS) 2. Jitter Buffers are required in packet-based communications, such as 3GPP MTSI 2, to smooth the inter-arrival jitter of i
36、ncoming media packets for uninterrupted playout. The solution is used in conjunction with the EVS decoder and can also be used for AMR 4 and AMR-WB 5. It is optimized for the Multimedia Telephony Service for IMS (MTSI) and fulfils the requirements for delay and jitter-induced concealment operations
37、set in 2. The present document is recommended for implementation in all network entities and UEs supporting the EVS codec. xCx 21.1 = 20.2 =11.1 =x 11.1 = 10.1 =21.1 =3GPP TS 26.448 version 13.0.0 Release 13In the case of discrepancy between the EVS JC code specification contained in 6, the procproc
38、edure described in the present document by 7 prevails. 4.2 Packet-based comIn packet-based communications, packets arrialso arrive out of order. Since the decoder expsamples in periodic blocks, a de-jitter buffer iof the de-jitter buffer, the better its ability to apackets are discarded. Voice commu
39、nicationsthe end to end delay as low as possible so thatThe defined adaptive Jitter Buffer Managemeattempting to minimize packet losses, the JBMas a result of the buffering. The JBM solutiontrade-off between delay and late losses. 4.3 EVS Receiver arcAn EVS receiver for MTSI-based communicaEVS Jitte
40、r Buffer Management solution the reto the Jitter Buffer Management (JBM). The Jplayout of the decoded EVS frames at the AcoFigure 1: Receiver architecFigure 1 illustrates the architecture and data fserves only as an example to outline the integmodule and its interfaces to the RTP DepackeModem and Ac
41、oustic Frontend are outside thDepacker is outlined in a basic form; more coReal-time implementations of this architecturRTP packets from the modem and for requesthandled by listening for packets received on tpushed into the RTP Depacker module whichpushed into the JBM where the statistics are uAcous
42、tic Frontend contains the audio interfacbuffers from the JBM. The JBM is therefore rdecoding EVS frames by the EVS decoder ordescribed for a multi-threaded architecture it dparticular implementation. Note that the JBM does not directly forward fbased adaptation to smooth the network jitter.ETSI ETSI
43、 TS 126 4487itter Buffer Management described in the present documrocedure defined by 6 prevails. In the case of discrepancand its ANSI-C code specification contained in 7, the ommunications rrive at the terminal with random jitters in their arrival timex ects to be fed a speech packet every 20 mill
44、iseconds tos required to absorb the jitter in the packet arrival time. o absorb the jitter in the arrival time and consequently fewns is also a delay critical system and therefore it becomeshat a two way conversation can be sustained. nt (JBM) solution reflects the above mentioned trade-ofalgorithm
45、in the receiver also keeps track of the delayion suitably adjusts the depth of the de-jitter buffer in orderchitecture overview ication is built on top of the EVS Jitter Buffer Managemene received EVS frames, contained in RTP packets, are depBM smoothes the inter-arrival jitter of incoming packetcou
46、stic Frontend of the terminal. te ture for the EVS Jitter Buffer Management Solua flow of the receiver side of an EVS terminal. Note that thration of the JBM in a terminal. This specification defincker, the EVS Decoder 2, and the Acoustic Frontend 8.the scope of the present document. The actual impl
47、ementacomplex depacketization scenarios depend on the usage otu e typically use independent processing threads for reactesting PCM data for the Acoustic Frontend. Arriving packthe network socket related to the RTP session. Incomingextracts the frames contained in an RTP packet. These pdated and the
48、frames are stored for later decoding andface which, concurrently to the push operation of EVS frame required to provide PCM buffers, which are normally geor by other means to allow uninterrupted playout. Althougit does not specify thread-safe data structures due to the dd frames from the RTP Depacke
49、r to the EVS decoder but ter In addition signal-based adaptation is executed on the dV13.0.0 (2016-01)cument and its ANSI-n y between the e procedure defined ti e. Packets may to output speech e. The larger the size er late arriving essential to keep offs. While la in packet delivery der to achieve the t solution. In the epacketized and fed ets for uninterrupted olution t the architecture fines the JBM The modules for ntation of the RTP f RTP. acting on arriving ckets are typically ng packets are s
