1、 ETSI TR 126 911 V15.0.0 (2018-07) 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 15.0.0 Release 15) TECHNICAL REPORT
2、GLOBAL SYSTEM FOR MOBILE COMMUNICATIONSRETSI ETSI TR 126 911 V15.0.0 (2018-07)13GPP TR 26.911 version 15.0.0 Release 15Reference RTR/TSGS-0426911vf00 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、SM logo are trademarks registered and owned by the GSM Association. ETSI ETSI TR 126 911 V15.0.0 (2018-07)23GPP TR 26.911 version 15.0.0 Release 15Intellectual Property Rights Essential patents IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The info
10、rmation pertaining to these essential 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
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12、e updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Trademarks The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners. ETSI claims no ownership of these except for any which are indicate
13、d as being the property of ETSI, and conveys no right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks. Foreword This Technical Re
14、port (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 GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables.
15、 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“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ are to be interpreted as described in clause
16、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 V15.0.0 (2018-07)33GPP TR 26.911 version 15.0.0 Release 15Contents Intellectual Property Rights 2g3Fore
17、word . 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 Multiplex Protocol 7g35.1 H.223 Multiplex Transmission Bit Order . 7g36 Control Protocol . 8g36.1 Usag
18、e 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 Other Audio Codecs . 11g39 Data Protocols 11g310 Terminal Procedures. 11g311 Interoperation with Other
19、Terminals 11g311.1 Audio Codecs . 11g312 DTE-DCE Interface 11g313 Optional Enhancements 11g314 Multipoint Considerations 12g315 Other Recommendations 12g3Annex A (informative): Change history . 13g3History 14g3ETSI ETSI TR 126 911 V15.0.0 (2018-07)43GPP TR 26.911 version 15.0.0 Release 15Foreword Th
20、is 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 formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released b
21、y 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 approval; 3 or greater indicates TSG approved document under change control. y the second digit is inc
22、remented 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. ETSI ETSI TR 126 911 V15.0.0 (2018-07)53GPP TR 26.911 version 15.0.0 Release 151 Scope The present docum
23、ent 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 7, and Annex C of ITU-T Recommendation H.324 7 in particular. These recommendations address issues s
24、pecific 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 assist in high quality implementation of multimedia telephony terminals. All references to “terminals“
25、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 this text, constitute provisions of the present document. - References are either specific (identified
26、 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-specific referenc
27、e 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“. 2 ITU-T Recommendation H.223 Annex A (1998): “Multiplexing protocol for low bit rate multime
28、dia 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 channels“. 4 ITU-T Recommendation H.223 Annex C (1998): “Multiplexing protocol for low bit rate mult
29、imedia 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 audiovisual services at px64 kbit/s“ 7 ITU-T Recommendation H.324 (2006): “Terminal for low bitrat
30、e 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 coding for low bit rate communication“ 10 3GPP TS 26.110: “Codec for Circuit Switched Multimedia T
31、elephony 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 Telephony Service; General description“. 13 3GPP TR 26.912: “Codec for Circuit Switched Multimedia T
32、elephony 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“. 15 ISO/IEC JTC1/SC29/WG11 MPEG 99/N2724: “MPEG-4 Applications“, March 1999. ETSI ETSI TR 126 911 V15
33、.0.0 (2018-07)63GPP TR 26.911 version 15.0.0 Release 1516 ITU-T Recommendation V.80: “In-band DCE control and synchronous data modes for asynchronous DTE“. 17 3rdGeneration Partnership Project (3GPP), 3GPP TS 25.301, Radio Interface Protocol Architecture. 18 ITU-T Recommendation H.264 (2003): “Advan
34、ced 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): “Extended video procedures and control signals for H.300 series terminals“ 3 Definitions, symbols a
35、nd 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 targeted for use in 3G mobile networks 3G-324M codec: implementation of ITU-T Recommendation H.324
36、 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: decoder part of the 3G-324M codec 3.2 Symbols (void) 3.3 Abbreviations For the purposes of the pres
37、ent 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 (Audio Codec) CIF: Common Intermediate Format (a picture format for Video Codec) CRC: Cyclic Redunda
38、ncy 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 Telephone Network ISDN: Integrated Services Digital Network ITU-T: International Telecommunication U
39、nion 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 (synchronization field for Video Codec) QCIF: Quarter CIF (a picture format for Video Codec) R
40、VLC: Reversible Variable Length Code (see 11) SQCIF: Sub QCIF (a picture format for Video Codec) SRP: Simple Retransmission Protocol T401: Acknowledgement timer used by ITU-T Recommendation H.245 5 implementations VOP: Video Object Plane (see 11) WNSRP: Windowed Numbered Simple Retransmission Protoc
41、ol ETSI ETSI TR 126 911 V15.0.0 (2018-07)73GPP TR 26.911 version 15.0.0 Release 154 General The following clauses give implementation recommendations for different parts of the 3G-324M codec. The clause division loosely follows the structure of ITU-T Recommendation H.324 7. Most of the recommendatio
42、ns 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 relevant for interoperability between 3G-324M terminals and other terminals. The recommendations
43、 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 emphasizing encoder recommendations over decoder recommendations, although this division cannot be made i
44、n 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 even if all recommendations in the present document are followed. 5 Multiplex Protocol Multiplexin
45、g 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 H.223 1. MUX-PDU size should be limited to be smaller than in typical GSTN use. Specific values
46、 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 Recommendation H.245 5 maxMUXPDUSizeCapability (clause 7.2.2.4 of 2 Version 3) to indicate that they are abl
47、e 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 of the MUX-PDUs, sent by the encoder, to a maximum of the specified number of octets. ITU-T Re
48、commendation 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 that do not start with a PSC should start with a GOB header to improve error resilience. ITU-T
49、 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 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 recommen
