ETSI TS 126 114 V19.3.0 (2026-04)

Universal Mobile Telecommunications System (UMTS); LTE; 5G; IP Multimedia Subsystem (IMS); Multimedia Telephony; Media handling and interaction (3GPP TS 26.114 version 19.3.0 Release 19)

RTS/TSGS-0426114vj30

General Information

• Status: Not Published
• Technical Committee: 3GPP SA 4 - Codec
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Completion Date: 02-Apr-2026

Standards Content (Sample)

TECHNICAL SPECIFICATION
Universal Mobile Telecommunications System (UMTS);
LTE;
5G;
IP Multimedia Subsystem (IMS);
Multimedia Telephony;
Media handling and interaction
(3GPP TS 26.114 version 19.3.0 Release 19)


3GPP TS 26.114 version 19.3.0 Release 19 1 ETSI TS 126 114 V19.3.0 (2026-04)

Reference
RTS/TSGS-0426114vj30
Keywords
5G,LTE,UMTS
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ETSI
3GPP TS 26.114 version 19.3.0 Release 19 2 ETSI TS 126 114 V19.3.0 (2026-04)
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ETSI
3GPP TS 26.114 version 19.3.0 Release 19 3 ETSI TS 126 114 V19.3.0 (2026-04)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 18
Introduction . 18
1 Scope . 19
2 References . 19
3 Definitions and abbreviations . 27
3.1 Definitions . 27
3.2 Abbreviations . 29
4 System description . 32
4.1 System . 32
4.2 Client . 32
4.3 MRFP and MGW . 34
5 Media codecs . 34
5.1 Media components . 34
5.2 Codecs for MTSI clients in terminals . 35
5.2.1 Speech . 35
5.2.1.1 General codec requirements . 35
5.2.1.2 Detailed codec requirements, AMR . 36
5.2.1.3 Detailed codec requirements, AMR-WB . 36
5.2.1.4 Detailed codec requirements, EVS . 36
5.2.1.5 Offering multiple audio bandwidths and multiple channels . 36
5.2.1.6 Codec preference order . 36
5.2.2 Video . 37
5.2.3 Real-time text . 39
5.2.4 Still Images . 39
6 Media configuration . 39
6.1 General . 39
6.2 Session setup procedures . 40
6.2.1 General . 40
6.2.1a RTP profile negotiation . 40
6.2.1a.1 General . 40
6.2.1a.2 Using SDPCapNeg in SDP offer . 41
6.2.1a.3 Answering to an SDP offer using SDPCapNeg . 41
6.2.2 Speech . 41
6.2.2.1 General . 41
6.2.2.2 Generating SDP offers . 43
6.2.2.3 Generating SDP answer . 47
6.2.3 Video . 56
6.2.3.1 Introduction . 56
6.2.3.2 Common Session Setup Procedures . 56
6.2.3.3 Coordination of Video Orientation (CVO) . 57
6.2.3.4 Video Region-of-Interest (ROI) . 58
6.2.3.5 RTP Retransmission . 60
6.2.3.6 Forward Error Correction (FEC) . 61
6.2.4 Text . 61
6.2.5 Bandwidth negotiation . 61
6.2.5.1 General . 61
6.2.5.2 Speech . 63
6.2.5.3 Video . 66
6.2.6 The Synchronization Info attribute "3gpp_sync_info" . 66
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6.2.7 Negotiated QoS parameters . 67
6.2.7.1 General . 67
6.2.7.2 Alignment of negotiated QoS parameters and b=AS bandwidth modifier . 68
6.2.7.3 Alignment of negotiated QoS parameters and a=bw-info attribute . 69
6.2.7.4 The a=3gpp-qos-hint SDP attribute. 69
6.2.7.4.1 General . 69
6.2.7.4.2 3gpp-qos-hint ABNF syntax and semantics . 69
6.2.7.4.3 Creating an SDP offer . 70
6.2.7.4.4 Creating an SDP answer . 70
6.2.7.4.5 Offerer receiving an SDP answer . 72
6.2.8 Delay Budget Information (DBI) Signaling . 73
6.2.9 ANBR Support attribute "anbr" . 73
6.2.10 Data channel . 74
6.2.10.1 General . 74
6.2.10.2 Generating SDP offer . 78
6.2.10.3 Generating SDP answer . 78
6.2.10.4 Receiving SDP answer . 79
6.2.11 Still Images . 80
6.2.12 The a=3gpp-bdc-used-by SDP attribute . 80
6.2.12.1 General . 80
6.2.12.2 3gpp-bdc-used-by ABNF syntax and semantics . 80
6.2.13 The a=3gpp-req-app SDP attribute . 81
6.2.13.1 General . 81
6.2.13.2 3gpp-req-app ABNF syntax and semantics . 81
6.3 Session control procedures . 82
7 Data transport . 83
7.1 General . 83
7.2 RTP profiles . 83
7.3 RTCP usage . 83
7.3.1 General . 83
7.3.2 Speech . 84
7.3.3 Video . 85
7.3.4 Real-time text . 86
7.3.5 Void . 86
7.3.6 Reduced-Size RTCP . 86
7.3.7 Video Region-of-Interest (ROI) Signaling . 87
7.3.8 Delay Budget Information (DBI) Signaling . 89
7.4 RTP payload formats for MTSI clients . 92
7.4.1 General . 92
7.4.2 Speech . 92
7.4.3 Video . 93
7.4.4 Real-time text . 93
7.4.5 Coordination of Video Orientation . 94
7.4.6 RTP Retransmission . 96
7.4.7 Forward Error Correction (FEC) . 96
7.4.8 Still Images . 96
7.5 Media flow . 96
7.5.1 General . 96
7.5.2 Media specific . 96
7.5.2.1 Speech . 96
7.5.2.1.1 General . 96
7.5.2.1.2 Default operation . 97
7.5.2.1.3 HSPA . 98
7.5.2.1.4 EGPRS. 98
7.5.2.1.5 GIP . 98
7.5.2.1.6 Initial codec mode for AMR and AMR-WB . 98
7.5.2.1.7 E-UTRAN and NR . 99
7.5.2.1.8 Initial codec mode for EVS . 99
7.5.2.1.9 Dual-mono . 99
7.5.2.1.10 Initial codec mode for IVAS . 99
7.5.2.2 Video . 99
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7.5.2.3 Text . 100
7.5.3 Media synchronization . 100
7.5.3.1 General . 100
7.5.3.2 Text . 100
7.5.4 ECN usage in RTP sessions . 100
7.5.5 Handling of bit-rate variations . 100
7.5.5.1 General . 100
7.5.5.2 Video . 101
7.5.5.3 Speech . 101
8 Jitter buffer management in MTSI clients in terminals . 102
8.1 General . 102
8.2 Speech . 102
8.2.1 Terminology . 102
8.2.2 Functional requirements for jitter-buffer management . 103
8.2.3 Minimum performance requirements for jitter-buffer management . 103
8.2.3.1 General . 103
8.2.3.2 Objective performance requirements . 104
8.2.3.2.1 General . 104
8.2.3.2.2 Jitter buffer delay criteria . 104
8.2.3.2.3 Jitter induced concealment operations . 105
8.2.3.3 Delay and error profiles . 106
8.2.3.4 Speech material for JBM minimum performance evaluation . 106
8.3 Video . 106
8.4 Text . 106
9 Packet-loss handling . 107
9.1 General . 107
9.2 Speech . 107
9.2.1 General . 107
9.2.2 Transmitting redundant frames . 107
9.2.3 Receiving redundant frames . 110
9.3 Video . 111
9.3.1 General . 111
9.3.2 Receiver behaviour . 111
9.3.3 Sender behaviour . 111
9.3.4 Recommendations for packet loss recovery mechanisms usage . 112
9.4 Text . 113
10 Adaptation . 113
10.1 General . 113
10.2 Speech . 113
10.2.0 General . 113
10.2.1 RTCP-APP with codec control requests . 115
10.2.1.1 General . 115
10.2.1.2 General Format of RTCP-APP packet with codec control requests . 115
10.2.1.2a Padding . 116
10.2.1.3 Redundancy Request . 117
10.2.1.4 Frame Aggregation Request . 117
10.2.1.5 Codec Mode Request . 118
10.2.1.6 Generation of RTP payloads for multiple codec control requests . 118
10.2.1.7 EVS Primary Rate Request . 119
10.2.1.8 EVS Bandwidth Request . 120
10.2.1.9 EVS Channel Aware Request . 121
10.2.1.10 EVS Primary mode to EVS AMR-WB IO mode Switching Request . 121
10.2.1.11 EVS AMR-WB IO mode to EVS Primary mode Switching Request . 123
10.2.1.12 IVAS Coded Format Request . 123
10.2.1.13 IVAS Immersive Bit Rate Request . 124
10.2.2 Example use cases . 125
10.2.3 SDP negotiation for RTCP-APP . 127
10.3 Video . 128
10.3.1 General . 128
10.3.2 Signaling mechanisms . 128
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10.3.3 Adaptation triggers . 130
10.3.4 Sender behavior, downswitching . 130
10.3.4.1 Downswitching divided into phases . 130
10.3.4.2 Rate reduction phase . 131
10.3.4.3 Delay recovery phase . 131
10.3.5 Sender behaviour, up-switching. 131
10.3.6 Receiver behaviour, down-switching . 132
10.3.7 Receiver behaviour, up-switch. 132
10.3.8 ECN triggered adaptation . 132
10.4 Text . 133
10.5 Explicit Congestion Notification . 134
10.6 Using the a=bw-info attribute for adaptation . 134
10.7 Access network bitrate recommendation . 134
10.7.1 General . 134
10.7.2 Relation to session signaling bitrate information . 135
10.7.3 Use with dynamic bitrate adaptation . 136
10.7.3.1 General . 136
10.7.3.2 Adaptation of sent media . 136
10.7.3.3 Adaptation of received media . 139
10.7.4 Message mapping for LTE access . 139
10.7.5 Message mapping for NR access . 139
11 Front-end handling . 140
11.1 General . 140
12 Inter-working . 141
12.1 General . 141
12.2 3G-324M . 141
12.2.1 General . 141
12.2.2 Codec usage . 141
12.2.2.1 General . 141
12.2.2.2 Text . 141
12.2.3 Payload format . 141
12.2.4 MTSI media gateway trans-packetization . 141
12.2.4.1 General . 141
12.2.4.2 Speech de-jitter buffer . 142
12.2.4.3 Video bitrate equalization . 142
12.2.4.4 Data loss detection . 142
12.2.4.5 Data integrity indication . 142
12.2.4.6 Packet size considerations . 143
12.2.4.6.0 General . 143
12.2.4.6.1 The Maximum Receive SDU Size attribute "3gpp_MaxRecvSDUSize" . 143
12.2.4.7 Setting RTP timestamps . 143
12.2.4.8 Protocol termination . 143
12.2.4.9 Media synchronization . 144
12.2.5 Session control . 144
12.3 GERAN/UTRAN CS inter-working . 144
12.3.0 3G-324M . 144
12.3.1 Codecs for MTSI media gateways . 144
12.3.1.1 Speech interworking between 3GPP PS access and CS GERAN/UTRAN. 144
12.3.1.1a Speech inter-working between fixed access and CS GERAN/UTRAN . 145
12.3.1.2 Text . 146
12.3.2 RTP payload formats for MTSI media gateways . 146
12.3.2.1 Speech . 146
12.3.2.2 Text . 147
12.3.3 Explicit Congestion Notification . 148
12.3.4 Codec switching procedures with SRVCC . 148
12.4 PSTN . 149
12.4.1 3G-324M . 149
12.4.2 Text . 149
12.5 GIP inter-working. 149
12.5.1 Text . 149
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12.5.2 Speech . 149
12.6 Void . 149
12.6.1 Void . 149
12.6.2 Void . 149
12.7 Inter-working with other IMS and non-IMS IP networks . 149
12.7.1 General .
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