ETSI TS 126 444 V19.0.1 (2026-03)

Universal Mobile Telecommunications System (UMTS); LTE; 5G; Codec for Enhanced Voice Services (EVS); Test sequences (3GPP TS 26.444 version 19.0.1 Release 19)

RTS/TSGS-0426444vj01

General Information

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

Standards Content (Sample)

TECHNICAL SPECIFICATION
Universal Mobile Telecommunications System (UMTS);
LTE;
5G;
Codec for Enhanced Voice Services (EVS);
Test sequences
(3GPP TS 26.444 version 19.0.1 Release 19)


3GPP TS 26.444 version 19.0.1 Release 19 1 ETSI TS 126 444 V19.0.1 (2026-03)

Reference
RTS/TSGS-0426444vj01
Keywords
5G,LTE,UMTS
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ETSI
3GPP TS 26.444 version 19.0.1 Release 19 2 ETSI TS 126 444 V19.0.1 (2026-03)
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ETSI
3GPP TS 26.444 version 19.0.1 Release 19 3 ETSI TS 126 444 V19.0.1 (2026-03)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 4
1 Scope . 5
2 References . 5
3 Definitions and abbreviations . 6
3.1 Definitions . 6
3.2 Abbreviations . 6
4 General . 6
4.1 Introduction . 6
5 Test sequence format . 7
5.1 Introduction to test sequence format . 7
5.2 File format . 7
6 EVS codec test sequences including error concealment of lost packets . 7
6.1 Introduction to test sequences . 7
6.2 Codec configuration . 7
6.3 EVS codec test sequences . 7
6.3.1 EVS encoder test sequences. 7
6.3.2 EVS decoder test sequences. 7
6.3.3 Test sequences for AMR-WB interoperable function . 8
6.3.4 Test sequences for jitter buffer management . 8
7 Conformance Testing . 8
7.1 Bit-exact Conformance. 8
7.2 Non-Bit-exact Conformance . 8
7.2.1 Overview . 8
7.2.2 Running the Tests . 9
Annex A: Tools Description (normative) . 11
A.1 Decoder Test . 11
A.1.1 General Considerations . 11
A.1.2 Metrics . 11
A.1.2.1 RMS Error Threshold . 11
A.1.2.2 Signal to Noise Ratio (SNR) . 12
A.1.2.3 Spectral Distortion . 12
A.1.3 Analysis Flow and Reporting . 13
A.2 Encoder Test . 14
A.2.1 General Consideration . 14
A.2.2 Metrics . 15
A.3 MOS-LQO Test . 16
A.3.1 General consideration . 16
A.3.2 Test Files . 17
A.3.3 Test Conditions . 18
A.3.4 Thresholds and Criteria . 19
A.4 Reference Implementations . 20
Annex B (informative): Change history . 22
History . 23

ETSI
3GPP TS 26.444 version 19.0.1 Release 19 4 ETSI TS 126 444 V19.0.1 (2026-03)
Foreword
rd
This Technical Specification has been produced by the 3 Generation 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 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 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 incorporated in the document.
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3GPP TS 26.444 version 19.0.1 Release 19 5 ETSI TS 126 444 V19.0.1 (2026-03)
1 Scope
The present document specifies the digital test sequences for the Enhanced Voice Services (EVS) Codec. These
sequences are used in conformance testing for implementations of the EVS Codec (3GPP TS 26.445), Voice Activity
Detection (VAD) (3GPP TS.26.451), Comfort Noise Generation (3GPP TS 26.449), Discontinuous Transmission
(DTX) (3GPP TS 26.450), Error Concealment of Lost Packets (3GPP TS 26.447), Jitter Buffer Management (JBM)
(3GPP TS 26.448), and AMR-WB Interoperable Function (3GPP TS 26.446). In addition, the present document
specifies procedures for conformance testing.
2 References
The following documents contain provisions which, through reference 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 version 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 Enhanced Voice Services (EVS); Detailed Algorithmic Description".
[3] 3GPP TS 26.451: "Codec for Enhanced Voice Services (EVS); Voice Activity Detection (VAD)".
[4] 3GPP TS 26.449: "Codec for Enhanced Voice Services (EVS); Comfort Noise Generation (CNG)
Aspects".
[5] 3GPP TS 26.450: "Codec for Enhanced Voice Services (EVS); Discontinuous Transmission
(DTX)".
[6] 3GPP TS 26.447: "Codec for Enhanced Voice Services (EVS); Error Concealment of Lost
Packets".
[7] 3GPP TS 26.442: " Codec for Enhanced Voice Services (EVS); ANSI C code (fixed-point)".
[8] 3GPP TS 26.443: "Codec for Enhanced Voice Services (EVS); ANSI C code (floating-point)".
[9] 3GPP TS 26.174: "Adaptive Multi-Rate - Wideband (AMR-WB) Speech Codec Test Sequences".
[10] 3GPP TS 26.446: "Codec for Enhanced Voice Services (EVS); AMR-WB Backward Compatible
Functions".
[11] 3GPP TS 26. 448: "Codec for Enhanced Voice Services (EVS); Jitter Buffer Management".
[12] 3GPP TS 26.452: "Codec for Enhanced Voice Services (EVS); ANSI C code; Alternative fixed-
point using updated basic operators".
[13] 3GPP TS 26.406: "General audio codec audio processing functions; Enhanced aacPlus general
audio codec; Conformance testing".
[14] 3GPP TS 26.274: "Audio codec processing functions; Extended Adaptive Multi-Rate - Wideband
(AMR-WB+) speech codec; Conformance testing".
[15] 3GPP TS 26.952: "Codec for Enhanced Voice Services (EVS); Performance Characterization".
[16] ITU-T Recommendation P.863 (03/2018): "Perceptual objective listening quality assessment".
[17] ITU-T Recommendation P.501 (03/2017): "Test signals for use in telephonometry".
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[18] ITU-R Recommendation BS.1387-1 (11/2001): "Method for objective measurements of perceived
audio quality".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in 3GPP TS 26.445 [2], 3GPP TS 26.451 [3],
3GPP TS 26.449 [4], 3GPP TS 26.450 [5], 3GPP TS 26.447 [6], 3GPP TS 26.448 [11], and 3GPP TS 26.446 [10]
apply.
3.2 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].
ACELP Algebraic Code-Excited Linear Prediction
AMR-WB Adaptive Multi Rate Wideband (codec)
CNG Comfort Noise Generator
DTX Discontinuous Transmission
EVS 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 Switched
PSTN Public Switched 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
4.1 Introduction
This specification provides digital test sequences which are necessary to test conformance for an implementation of the
EVS codec (TS 26.445 [2]), Voice Activity Detection (TS 26.451 [3]), Comfort Noise Generation (TS 26.449 [4]),
Discontinuous Transmission (TS 26.450 [5]), Concealment of Lost Packets (3GPP TS 26.447 [6]), Jitter Buffer
Management (JBM) (3GPP TS 26.448 [11]) and AMR-WB Interoperable Function (3GPP TS 26.446 [10]), and for the
testing of conformance for implementations of the ANSI C code in TS 26.442 [7], TS 26.443 [8] and TS 26.452 [12].
A standard compliant implementation of the above specifications shall pass conformance tests according to clause 7.
The necessary test sequences can be found in the corresponding ZIP files according to the attached Readme.txt file.
Clause 5 describes the format of the files, which contain the digital test sequences. Clause 6 describes the test sequences
for the EVS codec, including error concealment of lost packets, the AMR-WB interoperable function. the VAD,
comfort noise generation, discontinuous transmission, the AMR-WB interoperable function, the EVS jitter buffer
management, Clause 7 describes the conformance testing for implementations of the EVS codec.
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5 Test sequence format
5.1 Introduction to test sequence format
This clause provides information on the format of the digital test sequences for the EVS codec (TS 26.445 [2]), Voice
Activity Detection (TS 26.451 [3]), Comfort Noise Generation (TS 26.449 [4]), Discontinuous Transmission
(TS 26.449 [5]), and Error Concealment of Lost Packets (TS 26.447 [6]), Jitter Buffer Management (JBM) (3GPP TS
26.448 [11]), and AMR-WB Interoperable Function (3GPP TS 26.446 [10]).
5.2 File format
The test sequence files in PC (little-endian) byte order are provided in archive files (ZIP format, see the pointer file
Readme.txt which accompanies the present document).
Following decompression, three types of file are provided:
- Files for input to the speech encoder: *.INP
- Files for comparison with the encoder output and for input to the speech decoder: *.COD
- Files for comparison with the decoder output: *.OUT
- Files for input to the speech decoder with JBM *.RTP
- One mode control file for the mode switching test *.MOD
- Instructions how to operate the test sequences *TXT
6 EVS codec test sequences including error
concealment of lost packets
6.1 Introduction to test sequences
This clause provides information on the test sequences designed to exercise the EVS codec (TS 26.445 [2]).
6.2 Codec configuration
The speech encoder shall be configured as instructed in the readme file attached.
6.3 EVS codec test sequences
6.3.1 EVS encoder test sequences
The test sequences are provided and described in the ZIP archive.
The test sequences for encoder testing and instructions to operate the encoder are summarized in Readme_EVS_enc.txt.
6.3.2 EVS decoder test sequences
The test sequences for decoder testing and instructions to operate the decoder are summarized in Readme_EVS_dec.txt.
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6.3.3 Test sequences for AMR-WB interoperable function
The test sequences for the AMR-WB interoperable function include the test sequences defined in TS 26.174 [9], but
*.COD and *.OUT files are not identical to those provided by TS 26.174.
Readme_AMRWB_IO_enc.txt and Readme_AMRWB_IO_dec.txt summarized the input test sequences, output test
sequences, and instructions to execute the AMR-WB interoperable function test.
6.3.4 Test sequences for jitter buffer management
The input test sequences, the output sequences, and instructions to run the jitter buffer management test are summarized
in the Readme_JBM_dec.txt.
7 Conformance Testing
7.1 Bit-exact Conformance
For an implementation to be declared conformant according to the bit-exact conformance method, the encoder and
decoder output sequences of the implementation shall match bit-exactly the test sequences provided in the
corresponding ZIP files according to the attached Readme.txt file and in accordance with clause 6. This applies for all
implementations based on TS 26.442 [7], TS 26.443 [8] or TS 26.452 [12]. For fixed-point implementations based on
TS 26.442 [7] and TS 26.452 [12] this is the only conformance method.
7.2 Non-Bit-exact Conformance
7.2.1 Overview
If an implementation under test is based on the reference floating–point code (TS 26.443 [8]) and the output sequences
are not bit-exact to the test sequences according to clause 6, the non bit-exact conformance testing process defined here
shall be used to test the conformance.
A conformant floating-point implementation of the EVS codec shall be compliant to the reference specification in TS
26.443 [8] by implementing all the algorithmic steps of the EVS codec, further specified in 3GPP TS 26.445 (Detailed
Algorithmic Description) [2], 3GPP TS 26.451 (Voice Activity Detection (VAD)) [3], 3GPP TS 26.449 (Comfort Noise
Generation (CNG)) [4], 3GPP TS 26.450 (Discontinuous Transmission (DTX)) [5], 3GPP TS 26.447 (Packet Loss
Concealment (PLC) of Lost Packets) [6], and 3GPP TS 26.446 (AMR-WB Interoperable Function) [10].
If a floating-point implementation uses the Jitter Buffer Management (JBM) according to TS 26.448 [11], the
implementation shall be compliant to the reference specification in TS 26.443 [8] by implementing all the algorithmic
steps of 3GPP TS 26.448 (Jitter Buffer Management (JBM)).
An implementation shall be tested for non-bit-exact conformance using three specific tests:
- Decoder test comparing the implementation decoder with TS 26.443 [8] decoder.
- Encoder test comparing the implementation encoder with TS 26.443 [8] encoder.
- MOS-LQO verification comparing the implementation with TS 26.442 [7] implementation.
All three tests shall pass for the implementation to be declared conformant. The tests are described in more details in
Annex A.
Figure 7.1 shows the flow chart of the non bit-exact conformance process.
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3GPP TS 26.444 version 19.0.1 Release 19 9 ETSI TS 126 444 V19.0.1 (2026-03)

Figure 7.1: Non bit-exact conformance process
7.2.2 Running the Tests
The executables and scripts illustrating how to run the tests are included i
...