1、 ETSI TR 126 911 V14.0.0 (2017-04) Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); Codec(s) for Circuit-Switched (CS) multimedia telephony service; Terminal implementors guide (3GPP TR 26.911 version 14.0.0 Release 14) TECHNICAL REPORT
2、GLOBAL SYSTEM FOR MOBILE COMMUNICATIONSRETSI ETSI TR 126 911 V14.0.0 (2017-04)13GPP TR 26.911 version 14.0.0 Release 14Reference RTR/TSGS-0426911ve00 Keywords GSM,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 5
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9、Trade Marks registered and owned by the GSM Association. ETSI ETSI TR 126 911 V14.0.0 (2017-04)23GPP TR 26.911 version 14.0.0 Release 14Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these ess
10、ential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: “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 updat
11、es are available on the ETSI Web server (https:/ipr.etsi.org/). Pursuant to the ETSI IPR Policy, no investigation, 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 serve
12、r) which are, or may be, or may become, essential to the present document. Foreword This Technical Report (TR) 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 GS
13、M identities. These should be interpreted as being references to the corresponding ETSI deliverables. The 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 “should“, “should not“, “m
14、ay“, “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 “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TR 126 911 V1
15、4.0.0 (2017-04)33GPP TR 26.911 version 14.0.0 Release 14Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Definitions, symbols and abbreviations . 6g33.1 Definitions 6g33.2 Symbols 6g33.3 Abbreviations . 6g34 General . 7g35 M
16、ultiplex Protocol 7g35.1 H.223 Multiplex Transmission Bit Order . 7g36 Control Protocol . 8g36.1 Usage of DRAWING_ORDER-information for MPEG-4 video objects . 9g37 Video Codec . 9g37.1 General Recommendations . 9g37.2 H.263 9g37.3 Other Video Codecs . 10g38 Audio Codec . 11g38.1 AMR Codec 11g38.2 Ot
17、her Audio Codecs . 11g39 Data Protocols 11g310 Terminal Procedures. 11g311 Interoperation with Other Terminals 11g311.1 Audio Codecs . 11g312 DTE-DCE Interface 12g313 Optional Enhancements 12g314 Multipoint Considerations 12g315 Other Recommendations 12g3Annex A (informative): Change history . 13g3H
18、istory 14g3ETSI ETSI TR 126 911 V14.0.0 (2017-04)43GPP TR 26.911 version 14.0.0 Release 14Foreword This Technical Report has been produced by the 3rdGeneration Partnership Project (3GPP). The contents of the present document are subject to continuing work within the TSG and may change following form
19、al 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; 2 presented to TSG for a
20、pproval; 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 incorporated in the document. ETS
21、I ETSI TR 126 911 V14.0.0 (2017-04)53GPP TR 26.911 version 14.0.0 Release 141 Scope The present document provides non-mandatory recommendations for the use of the different codec implementation options for the circuit switched multimedia telephony service which is based on ITU-T Recommendation H.324
22、 7, and Annex C of ITU-T Recommendation H.324 7 in particular. These recommendations address issues specific to the 3G operating environment, including guaranteeing sufficient error resilience and interworking between terminals. The contents of the present document are provided for information to as
23、sist in high quality implementation of multimedia telephony terminals. All references to “terminals“ in this report are to terminals supporting the Circuit Switched Multimedia Telephony Service as described in 7-9. 2 References The following documents contain provisions which, through reference in t
24、his 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 version applies. In
25、 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 ITU-T Recommendation H.223 (1996): “Multiplexing protocol for low bit rate multimedia communication
26、“. 2 ITU-T Recommendation H.223 Annex A (1998): “Multiplexing protocol for low bit rate multimedia mobile communication over low error-prone channels“. 3 ITU-T Recommendation H.223 Annex B (1998): “Multiplexing protocol for low bit rate multimedia mobile communication over moderate error-prone chann
27、els“. 4 ITU-T Recommendation H.223 Annex C (1998): “Multiplexing protocol for low bit rate multimedia mobile communication over highly error-prone channels“. 5 ITU-T Recommendation H.245 (2000): “Control protocol for multimedia communication“ 6 ITU-T Recommendation H.261 (1993): “Video codec for aud
28、iovisual services at px64 kbit/s“ 7 ITU-T Recommendation H.324 (2006): “Terminal for low bitrate multimedia communication“ 8 ITU-T Recommendation G.723.1 (1996): “Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s“. 9 ITU-T Recommendation H.263 (1998): “Video cod
29、ing for low bit rate communication“ 10 3GPP TS 26.110: “Codec for Circuit Switched Multimedia Telephony Service: General Description“. 11 3GPP TS 26.111: “Codec for Circuit Switched Multimedia Telephony Service, Modifications to H.324“. 12 3GPP TS 26.112: “Codec for Circuit Switched Multimedia Telep
30、hony Service; General description“. 13 3GPP TR 26.912: “Codec for Circuit Switched Multimedia Telephony Service; Quantitative performance evaluation of H.324 Annex C over 3G“. 14 International Standard ISO/IEC 14496-2: “Information technology - Coding of audio-visual objects - Part 2: Visual“. ETSI
31、ETSI TR 126 911 V14.0.0 (2017-04)63GPP TR 26.911 version 14.0.0 Release 1415 ISO/IEC JTC1/SC29/WG11 MPEG 99/N2724: “MPEG-4 Applications“, March 1999. 16 ITU-T Recommendation V.80: “In-band DCE control and synchronous data modes for asynchronous DTE“. 17 3rdGeneration Partnership Project (3GPP), 3GPP
32、 TS 25.301, Radio Interface Protocol Architecture. 18 ITU-T Recommendation H.264 (2003): “Advanced video coding for generic audiovisual services“ | ISO/IEC 14496-10:2003: “Information technology Coding of audio-visual objects Part 10: Advanced Video Coding“ 19 ITU-T Recommendation H.241 (2003): “Ext
33、ended video procedures and control signals for H.300 series terminals“ 3 Definitions, symbols and abbreviations 3.1 Definitions For the purposes of the present document, the following terms and definitions apply: 3G-324M terminal: multimedia telephony terminal conforming to 3GPP TS 26.110 10 and tar
34、geted for use in 3G mobile networks 3G-324M codec: implementation of ITU-T Recommendation H.324 7 and all its elements adapted to the 3G environment (known as 3G-324M) is seen as a “codec“ consisting of an encoder and a decoder 3G-324M encoder: encoder part of the 3G-324M codec 3G-324M decoder: deco
35、der part of the 3G-324M codec 3.2 Symbols (void) 3.3 Abbreviations For the purposes of the present document, the following abbreviations apply: AL1,2,3: ITU-T Recommendation H.223 2 Adaptation layers 1, 2 and 3 (see 1) AL-SDU: Adaptation Layer Service Data Unit (see 1) AMR: Adaptive Multi-Rate (Audi
36、o Codec) CIF: Common Intermediate Format (a picture format for Video Codec) CRC: Cyclic Redundancy Check DCE: Data Circuit-terminating Equipment DTE: Data Terminal Equipment GOB: Group of blocks (a sub-part of a video picture) GSM: Global System for Mobile communications GSTN: General Switched Telep
37、hone Network ISDN: Integrated Services Digital Network ITU-T: International Telecommunication Union Telecommunication Standardization Sector MONA: Media Oriented Negotiation Acceleration MUX-PDU: Multiplex Packet Data Unit (see 1) NSRP: Numbered Simple Retransmission Protocol PSC: Picture start code
38、 (synchronization field for Video Codec) QCIF: Quarter CIF (a picture format for Video Codec) RVLC: Reversible Variable Length Code (see 11) SQCIF: Sub QCIF (a picture format for Video Codec) SRP: Simple Retransmission Protocol ETSI ETSI TR 126 911 V14.0.0 (2017-04)73GPP TR 26.911 version 14.0.0 Rel
39、ease 14T401: Acknowledgement timer used by ITU-T Recommendation H.245 5 implementations VOP: Video Object Plane (see 11) WNSRP: Windowed Numbered Simple Retransmission Protocol 4 General The following clauses give implementation recommendations for different parts of the 3G-324M codec. The clause di
40、vision loosely follows the structure of ITU-T Recommendation H.324 7. Most of the recommendations in the present document assume that both transmitting and receiving terminals operate within the 3G system and conform to 3G-324M specifications in 7-9. Clause 11 additionally includes recommendations r
41、elevant for interoperability between 3G-324M terminals and other terminals. The recommendations are primarily targeted for such aspects of the codec implementation which have a significant effect on the quality perceived by the user at the other end of the connection which usually implies emphasizin
42、g encoder recommendations over decoder recommendations, although this division cannot be made in all cases. It should be recognized that the ITU-T Recommendation H.324 7 specification leaves substantial amount of freedom for terminal implementations and no definite quality guarantee can be given eve
43、n if all recommendations in the present document are followed. 5 Multiplex Protocol Multiplexing of video, audio, data, and control information is based on the ITU-T Recommendation H.223 1. The following general guidelines are recommended to be followed in the implementation of ITU-T Recommendation
44、H.223 1. MUX-PDU size should be limited to be smaller than in typical GSTN use. Specific values depend on the bit-rate and channel characteristics, but suitable upper limits for MUX-PDU size are often in the range of 100-200 octets. Encoders are recommended to support the boolean ITU-T Recommendatio
45、n H.245 5 maxMUXPDUSizeCapability (clause 7.2.2.4 of 2 Version 3) to indicate that they are able to restrict the size of the MUX-PDUs that they transmit. Decoders are recommended to utilize the maxH223MUXPDUsize ITU-T Recommendation H.245 5 command (clause 7.11.5 of 2 Version 3) to restrict the size
46、 of the MUX-PDUs, sent by the encoder, to a maximum of the specified number of octets. ITU-T Recommendation H.324 7 mandates that ITU-T Recommendation H.263 9 encoders shall align picture start codes (PSC) with the start of an AL-SDU (see 4, clause 6.6.1). It is here further recommended that AL-SDUs
47、 that do not start with a PSC should start with a GOB header to improve error resilience. ITU-T Recommendation H.241 19 mandates that ITU-T Recommendation H.264 18 encoders shall align Annex B/H.264 start code prefix for the first NAL unit of each access unit with the start of an AL-SDU. Use of the
48、NAL Alignment Mode defined in TS 26.111 11 is here further recommended. No more than 1-3 audio frames should be included in one MUX-PDU to avoid excessive delay. Use of the optional retransmission procedure for video when using Adaptation Layer Type 3 (AL3) is not recommended due to delay considerat
49、ions. This recommendation implies that receiving terminals should not send retransmission requests. It is recommended that terminals support video also using Adaptation Layer Type 2 (AL2) where retransmission is not possible and overhead is slightly smaller. The ITU-T Recommendation H.223 1 abort procedures should not be used (see ITU-T Recommendation H.223 1 clauses 6.4.3, 7.2.3, 7.3.4, and 7.4.4). 5.1 H.223 Multiplex Transmission Bit Order H.223 multiplex trans
