Speech and multimedia Transmission Quality (STQ) - Speech Quality performance in the presence of background noise - Part 3: Background noise transmission - Objective test methods

The present document aims to identify and define testing methodologies which can be used to objectively evaluate the
performance of narrowband and wideband terminals and systems for speech communication in the presence of
background noise.
Background noise is a problem in mostly all situations and conditions and need to be taken into account in both,
terminals and networks. The present document provides information about the testing methods applicable to objectively
evaluate the speech quality in the presence of background noise. The present document includes:
• The description of the experts post evaluation process chosen to select the subjective test data being within the
scope of the objective methods.
• The results of the performance evaluation of the currently existing methods described in Recommendations
ITU-T P.862 [i.16] and P.862.1 [i.17] and in TOSQA2001 [i.19] which is chosen for the evaluation of
terminals in the framework of ETSI VoIP speech quality test events [i.8], [i.9], [i.10] and [i.11].
• The method which is applicable to objectively determine the different parameters influencing the speech
quality in the presence of background noise taking into account:
- the speech quality;
- the background noise transmission quality;
- the overall quality.
• The present document is to be used in conjunction with:
- ETSI ES 202 396-1 [i.1] which describes a recording and reproduction setup for realistic simulation of
background noise scenarios in lab-type environments for the performance evaluation of terminals and
communication systems.
- ETSI EG 202 396-2 [i.2] which describes the simulation of network impairments and how to simulate
realistic transmission network scenarios and which contains the methodology and results of the
subjective scoring for the data forming the basis of the present document.
- French speech sentences as defined in Recommendation ITU-T P.501 [i.13] for wideband and English
speech sentences as defined in Recommendation ITU-T P.501 [i.13] for narrowband.

Kakovost prenosa govora in večpredstavnih vsebin (STQ) - Zmogljivost kakovosti govora v prisotnosti šuma ozadja - 3. del: Prenos šuma ozadja - Objektivne preskusne metode

Cilj tega dokumenta je opredelitev preskusnih metod za objektivno vrednotenje zmogljivosti ozko- in širokopasovnih terminalov in sistemov za govorno komunikacijo v prisotnosti šuma ozadja.
Šum ozadja je težava v skoraj vseh situacijah in pogojih, zato ga je treba upoštevati tako v terminalih kot omrežjih. V tem dokumentu so podane informacije o preskusnih metodah za objektivno vrednotenje kakovosti govora v prisotnosti šuma ozadja. Ta dokument vključuje naslednje:
• Opis izbranega postopka strokovnega naknadnega vrednotenja za izbiro subjektivnih preskusnih podatkov v obsegu objektivnih metod.
• Rezultati vrednotenja zmogljivosti trenutnih metod, opisanih v priporočilih ITU-T P.862 [i.16] in P.862.1 [i.17] ter v dokumentu TOSQA2001 [i.19], ki so izbrane za vrednotenje terminalov v okviru preskušanja kakovosti govora ETSI VoIP [i.8], [i.9], [i.10] in [i.11].
• Metoda za objektivno določanje različnih parametrov, ki vplivajo na kakovost govora v prisotnosti šuma ozadja, pri čemer se upošteva:
– kakovost govora;
– kakovost prenosa šuma ozadja;
– splošna kakovost.
• Ta dokument je namenjen za uporabo v povezavi s:
– standardom ETSI ES 202 396-1 [i.1], ki opisuje snemanje in reprodukcijo za realistično simulacijo
scenarijev s šumom ozadja v laboratorijskih okoljih za vrednotenje zmogljivosti terminalov in
komunikacijskih sistemov;
– standardom ETSI EG 202 396-2 [i.2], ki opisuje simulacijo motenj v omrežju in
realističnih scenarijev omrežja za prenos ter vključuje metode in rezultate subjektivnega točkovanja za podatke, ki predstavljajo osnovo tega dokumenta;
– stavki v francoskem jeziku, kot je opredeljeno v priporočilu ITU-T P.501 [i.13] za širokopasovno omrežje, in stavki
v angleškem jeziku, kot je opredeljeno v priporočilu ITU-T P.501 [i.13] za ozkopasovno omrežje.

General Information

Status
Published
Publication Date
06-Jan-2016
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
05-Nov-2015
Due Date
10-Jan-2016
Completion Date
07-Jan-2016

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ETSI EG 202 396-3 V1.5.1 (2015-10)
ETSI GUIDE
Speech and multimedia Transmission Quality (STQ);
Speech Quality performance
in the presence of background noise;
Part 3: Background noise transmission -
Objective test methods
---------------------- Page: 1 ----------------------
2 ETSI EG 202 396-3 V1.5.1 (2015-10)
Reference
REG/STQ-229
Keywords
noise, QoS, quality, speech
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 à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88
Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search

The present document may be made available in electronic versions and/or in print. The content of any electronic and/or

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print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat.

Users of the present document should be aware that the document may be subject to revision or change of status.

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Copyright Notification

No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying

and microfilm except as authorized by written permission of ETSI.

The content of the PDF version shall not be modified without the written authorization of ETSI.

The copyright and the foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 2015.
All rights reserved.
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DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.

3GPP 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
---------------------- Page: 2 ----------------------
3 ETSI EG 202 396-3 V1.5.1 (2015-10)
Contents

Intellectual Property Rights ................................................................................................................................ 5

Foreword ............................................................................................................................................................. 5

Modal verbs terminology .................................................................................................................................... 5

1 Scope ........................................................................................................................................................ 6

2 References ................................................................................................................................................ 6

2.1 Normative references ......................................................................................................................................... 6

2.2 Informative references ........................................................................................................................................ 7

3 Symbols and abbreviations ....................................................................................................................... 8

3.1 Symbols .............................................................................................................................................................. 8

3.2 Abbreviations ..................................................................................................................................................... 8

4 Speech signals to be used ......................................................................................................................... 9

5 Selection of the data within the scope of the wideband objective model: Experts evaluation ............... 10

5.1 Selection process .............................................................................................................................................. 10

5.2 Results .............................................................................................................................................................. 10

5.3 French database ................................................................................................................................................ 11

6 Description of the wideband objective test method ............................................................................... 11

6.1 Introduction ...................................................................................................................................................... 11

6.2 Speech sample preparation and nomenclature .................................................................................................. 12

6.2.1 Speech sample preparation ......................................................................................................................... 12

6.2.2 Nomenclature .............................................................................................................................................. 14

6.3 Additional Training data .................................................................................................................................. 15

6.4 Principles of Relative Approach and Δ Relative Approach .............................................................................. 15

6.5 Objective N-MOS............................................................................................................................................. 19

6.5.1 Introduction................................................................................................................................................. 19

6.5.2 Description of N-MOS algorithm ............................................................................................................... 19

6.5.3 Comparing subjective and objective N-MOS results .................................................................................. 22

6.6 Objective S-MOS ............................................................................................................................................. 23

6.6.1 Introduction................................................................................................................................................. 23

6.6.2 Description of S-MOS Algorithm ............................................................................................................... 24

6.6.3 Comparing Subjective and Objective S-MOS Results ................................................................................ 27

6.7 Objective G-MOS............................................................................................................................................. 28

6.7.1 Description of G-MOS Algorithm .............................................................................................................. 28

6.7.2 Comparing subjective and objective G-MOS results .................................................................................. 29

7 Validation of the Wideband Objective Test Method .............................................................................. 30

7.1 Introduction ...................................................................................................................................................... 30

7.2 ETSI EG 202 396-2 Database Results Analysis ............................................................................................... 32

7.2.1 Comparing subjective and objective N-MOS results .................................................................................. 32

7.2.2 Comparing subjective and objective S-MOS results .................................................................................. 32

7.2.3 Comparing Subjective and Objective G-MOS Results ............................................................................... 33

7.3 Orange Validation Database results Analysed ................................................................................................. 34

7.3.0 Introduction................................................................................................................................................. 34

7.3.1 Comparing subjective and objective N-MOS results .................................................................................. 34

7.3.2 Comparing subjective and objective S-MOS results .................................................................................. 35

7.3.3 Comparing Subjective and Objective G-MOS Results ............................................................................... 35

8 Objective Model for Narrowband Applications ..................................................................................... 36

8.0 Introduction ...................................................................................................................................................... 36

8.1 File pre-processing ........................................................................................................................................... 36

8.2 Adaptation of the Calculations ......................................................................................................................... 37

8.3 Prediction results .............................................................................................................................................. 38

Annex A: Detailed post evaluation of listening test results ................................................................ 40

Annex B: Results of PESQ and TOSQA2001 - Analysis of ETSI EG 202 396-2 database .............. 43

ETSI
---------------------- Page: 3 ----------------------
4 ETSI EG 202 396-3 V1.5.1 (2015-10)

Annex C: Comparison of objective MOS versus auditory MOS for the complete STF 294

database ................................................................................................................................. 50

Annex D: Comparison of objective MOS versus auditory MOS for rejected conditions ................ 52

Annex E: Void ........................................................................................................................................ 54

Annex F: Detailed STF 294 subjective and objective validation test results .................................... 55

Annex G: Void ........................................................................................................................................ 58

Annex H: Extension of the Speech Quality Test Method to Narrowband: Adaptation,

Training and Validation ....................................................................................................... 59

Annex I: Void ........................................................................................................................................ 61

Annex J: Summary of Czech samples not used for model training .................................................. 62

J.0 Introduction ...................................................................................................................................................... 62

J.1 Selection process - Czech database ........................................................................................................ 62

J.2 General differences between the databases ............................................................................................ 64

J.3 Comparison of the objective method results for Czech and French samples ......................................... 67

J.4 Czech conditions results analysis ........................................................................................................... 72

J.4.1 Comparing subjective and objective N-MOS results ....................................................................................... 72

J.4.2 Comparing subjective and objective S-MOS results ........................................................................................ 72

J.4.3 Comparing Subjective and Objective G-MOS Results..................................................................................... 73

J.5 Language Dependent Robustness of G-MOS......................................................................................... 74

J.6 Regression Coefficients for Czech data ................................................................................................. 75

J.7 Post selection .......................................................................................................................................... 76

Annex K: Relative Approach Non-Linear Transformation ............................................................... 80

Annex L: Bibliography .......................................................................................................................... 81

History .............................................................................................................................................................. 82

ETSI
---------------------- Page: 4 ----------------------
5 ETSI EG 202 396-3 V1.5.1 (2015-10)
Intellectual 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 000 314: "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 updates are available on the ETSI Web

server (http://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

server) which are, or may be, or may become, essential to the present document.
Foreword

This ETSI Guide (EG) has been produced by ETSI Technical Committee Speech and multimedia Transmission Quality

(STQ).

The present document is a deliverable of ETSI Specialized Task Force (STF) 294 entitled: "Improving the quality of

eEurope wideband speech applications by developing a performance testing and evaluation methodology for

background noise transmission".

The present document is part 3 of a multi-part deliverable covering Speech and multimedia Transmission Quality

(STQ); Speech Quality performance in the presence of background noise, as identified below:

Part 1: "Background noise simulation technique and background noise database";

Part 2: "Background noise transmission - Network simulation - Subjective test database and results";

Part 3: "Background noise transmission - Objective test methods".
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 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
---------------------- Page: 5 ----------------------
6 ETSI EG 202 396-3 V1.5.1 (2015-10)
1 Scope

The present document aims to identify and define testing methodologies which can be used to objectively evaluate the

performance of narrowband and wideband terminals and systems for speech communication in the presence of

background noise.

Background noise is a problem in mostly all situations and conditions and need to be taken into account in both,

terminals and networks. The present document provides information about the testing methods applicable to objectively

evaluate the speech quality in the presence of background noise. The present document includes:

• The description of the experts post evaluation process chosen to select the subjective test data being within the

scope of the objective methods.

• The results of the performance evaluation of the currently existing methods described in Recommendations

ITU-T P.862 [i.16] and P.862.1 [i.17] and in TOSQA2001 [i.19] which is chosen for the evaluation of

terminals in the framework of ETSI VoIP speech quality test events [i.8], [i.9], [i.10] and [i.11].

• The method which is applicable to objectively determine the different parameters influencing the speech

quality in the presence of background noise taking into account:
- the speech quality;
- the background noise transmission quality;
- the overall quality.
• The present document is to be used in conjunction with:

- ETSI ES 202 396-1 [i.1] which describes a recording and reproduction setup for realistic simulation of

background noise scenarios in lab-type environments for the performance evaluation of terminals and

communication systems.

- ETSI EG 202 396-2 [i.2] which describes the simulation of network impairments and how to simulate

realistic transmission network scenarios and which contains the methodology and results of the

subjective scoring for the data forming the basis of the present document.

- French speech sentences as defined in Recommendation ITU-T P.501 [i.13] for wideband and English

speech sentences as defined in Recommendation ITU-T P.501 [i.13] for narrowband.
2 References
2.1 Normative references

References are either specific (identified by date of publication and/or edition number or version number) or

non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the

reference document (including any amendments) applies.

Referenced documents which are not found to be publicly available in the expected location might be found at

http://docbox.etsi.org/Reference.

NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee

their long term validity.

The following referenced documents are necessary for the application of the present document.

Not applicable.
ETSI
---------------------- Page: 6 ----------------------
7 ETSI EG 202 396-3 V1.5.1 (2015-10)
2.2 Informative references

References are either specific (identified by date of publication and/or edition number or version number) or

non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the

reference document (including any amendments) applies.

NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee

their long term validity.

The following referenced documents are not necessary for the application of the present document but they assist the

user with regard to a particular subject area.

[i.1] ETSI ES 202 396-1: "Speech and multimedia Transmission Quality (STQ); Speech quality

performance in the presence of background noise; Part 1: Background noise simulation technique

and background noise database".

[i.2] ETSI EG 202 396-2: "Speech Processing, Transmission and Quality Aspects (STQ); Speech

Quality performance in the presence of background noise; Part 2: Background Noise Transmission

- Network Simulation - Subjective Test Database and Results".

[i.3] Recommendation ITU-T P.835: "Subjective test methodology for evaluating speech

communication systems that include noise suppression algorithm".

[i.4] Recommendation ITU-T P.800: "Methods for subjective determination of transmission quality".

[i.5] Recommendation ITU-T P.831: "Subjective performance evaluation of network echo cancellers".

[i.6] Genuit, K.: "Objective Evaluation of Acoustic Quality Based on a Relative Approach",

InterNoise '96, Liverpool, UK.

[i.7] Recommendation ITU-T SG 12 Contribution 34: "Evaluation of the quality of background noise

transmission using the "Relative Approach"".

[i.8] ETSI 2 Speech Quality Test Event: "Anonymized Test Report", ETSI Plugtests, HEAD

acoustics, T-Systems Nova.

NOTE: Available at: http://www.etsi.org/WebSite/OurServices/Plugtests/History.aspx. Also available as ETSI

TR 102 648-3.
[i.9] ETSI 3 Speech Quality Test Event: "Anonymized Test Report "IP Gateways".

NOTE: Available at: http://www.etsi.org/WebSite/OurServices/Plugtests/History.aspx.

[i.10] ETSI 3 Speech Quality Test Event: "Anonymized Test Report "IP Phones".

[i.11] ETSI 4 Speech Quality Test Event: "Anonymized Test Report "IP Gateways and IP Phones".

NOTE: Available at: http://www.etsi.org/WebSite/OurServices/Plugtests/History.aspx.

[i.12] F. Kettler, H.W. Gierlich, F. Rosenberger: "Application of the Relative Approach to Optimize

Packet Loss Concealment Implementations", DAGA, March 2003, Aachen, Germany.
[i.13] Recommendation ITU-T P.501: "Test Signals for Use in Telephonometry".

[i.14] R. Sottek, K. Genuit: "Models of Signal Processing in human hearing", International Journal of

Electronics and Communications (AEÜ) volume 59, 2005, p. 157-165.
NOTE: Available at: http://www.elsevier.de/aeue.

[i.15] SAE International - Document 2005-01-2513: "Tools and Methods for Product Sound Design of

Vehicles" R. Sottek, W. Krebber, G. Stanley.

[i.16] Recommendation ITU-T P.862: "Perceptual evaluation of speech quality (PESQ): An objective

method for end-to-end speech quality assessment of narrowband telephone networks and speech

codecs".
ETSI
---------------------- Page: 7 ----------------------
8 ETSI EG 202 396-3 V1.5.1 (2015-10)

[i.17] Recommendation ITU-T P.862.1: "Mapping function for transforming P.862 raw result scores to

MOS-LQO".

[i.18] Recommendation ITU-T P.862.2: "Wideband extension to Recommendation P.862 for the

assessment of wideband telephone networks and speech codecs".

[i.19] Recommendation ITU-T SG 12 Contribution 19: "Results of objective speech quality assessment

of wideband speech using the Advanced TOSQA2001".
[i.20] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".

[i.21] Recommendation ITU-T G.722.2: "Wideband coding of speech at around 16 kbit/s using Adaptive

Multi-Rate Wideband (AMR-WB)".

[i.22] Recommendation ITU-T P.56: "Objective measurement of active speech level".

[i.23] Recommendation ITU-T P.57: "Artificial ears".
[i.24] M. Spiegel: "Theory and problems of statistics", McGraw Hill, 1998.
[i.25] Void.

[i.26] M. Kendall: "Rank correlation methods", Charles Griffin & Company Limited, 1948.

[i.27] Sottek, R.: "Modelle zur Signalverarbeitung im menschlichen Gehör", PHD thesis RWTH Aachen,

1993.

[i.28] Recommendation ITU-T P.830: "Subjective performance assessment of telephone-band and

wideband digital codecs".
[i.29] Void.

[i.30] ANSI S1.1-1986 (ASA 65-1986): "Specifications for Octave-Band and Fractional-Octave-Band

Analog and Digital Filters", 1993.

[i.31] Recommendation ITU-T G.160 Appendix II, Amendment 2: "Voice enhancement devices:

Revised Appendix II - Objective measures for the characterization of the basic functioning of

noise reduction algorithms".

[i.32] ETSI TS 103 106: "Speech and multimedia Transmission Quality (STQ); Speech quality

performance in the presence of background noise: Background noise transmission for mobile

terminals-objective test methods".

[i.33] Hastie, T.; Tibshirani, R.; Friedman, J.: "The Elements of Statistical Learning: Data Mining,

Inference, and Prediction", New York: Springer-Verlag, 2001.
3 Symbols and abbreviations
3.1 Symbols
For the purposes of the present document, the following symbols apply:
σ Variance
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AMR Adaptive MultiRate
ASL Active Speech Level
NOTE: According to Recommendation ITU-T P.56 [i.22].
ETSI
---------------------- Page: 8 ----------------------
9 ETSI EG 202 396-3 V1.5.1 (2015-10)
BGN BackGround Noise
CDF Cumulative Density Function
dB SPL Sound Pressure Level re 20 µPa in dB
DB Data Base
DUT Device Under Test
EFR Enhance Full Rate
FR Full Rate
G-MOS Global MOS
NOTE: MOS related to the overall sample.
GSM Global System for Mobile Communication
HATS Head And Torso Simulator
IP Internet Protocol
IRS Intermediate Reference System
ITU International Telecommunication Union
ITU-T Telecom Standardization Body of ITU
MMSE Minimum Mean Square Error
MOS Mean Opinion Score
MOS-LQSN Mean Opinion Score - Listening Quality Subjective Noise
MRP Mouth Reference Point
NB NarrowBand
NI Network I conditions
NII Network II conditions
NIII Network III conditions
N-MOS Noise MOS
NOTE: MOS related to the noise transmission only.
NR Noise Reduction
NR (filter) Noise Reduction (filter)
NSA Noise Suppression Algorithm
PESQ Perceptual Evaluation of Speech Quality
PLC Packet Loss Concealment
RCV ReCeiVe
RMS Root Mean Square
RMSE Random Mean Square Error
S-MOS Speech MOS
NOTE: MOS related to the speech signal only.
SND Sending Direction
SNR Signal to Noise Ratio
SQTE Speech Quality Test Event
SPL Sound Pressure Level
STD STandard Deviation
STF Specialized Task Force
TMOS TOSQA Mean Opinion Score
TOR Terms Of Reference
VAD Voice Activity Detection
VoIP Voice over IP
WB WideBand
4 Speech signals to be used

As with any objective model, the prediction of speech quality depends on the conditions under which the model was

tested and validated (see clauses 6.1 and 8). This dependency also applies to the speech material used in conjunction

with the objective model.

The wideband version of the model uses French speech sentences. The near end speech signal (clean speech signal)

consists of 8 sentences of speech (2 male and 2 female talkers, 2 sentences each). Appropriate speech samples can be

taken from Recommendation ITU-T P.501 [i.13].
ETSI
---------------------- Page: 9 ----------------------
10 ETSI EG 202 396-3 V1.5.1 (2015-10)

The narrowband version of the model uses English speech sentences. The near end speech signal (clean speech signal)

consists of 8 sentences of speech (2 male and 2 female talkers, 2 sentences each). Appropriate speech samples can be

taken from Recommendation ITU-T P.501 [i.13].
5 Selection of the data within the scope of the
wideband objective model: Experts evaluation
5.1 Selection process

The aim of the selection process was to identify those data in the databases described in ETSI EG 202 396-2 [i.2] which

are consistent with the scope of the objective models to be studied within the present document.

The experts were selected on the based on the definition found in e.g. Recommendation ITU-T P.831 [i.5]: experts are

experienced in subjective testing. Experts are able to describe an auditory event in detail and are able to separate

different events based on specific impairments. They are able to describe their subjective impressions in detail. They

have a background in technical implementations of noise reduction systems and transmission impairments and do have

detailed knowledge of the influence of particular implementations on subjective quality.

Their task was to select the relevant conditions within the scope of the model to be developed. Therefore they had to

verify the consistency of the data with respect to the following selection criteria:

1) Artefacts others than the ones which should have been produced by the signal processing described in ETSI

EG 202 396-2 [i.2] e.g. due to the additional amplification required in order to provide a listening level of

79 dB SPL.

2) Inconsistencies within one condition due to the selection of the individual speech samples from the database

for subjective evaluation.

3) Inconsistencies within one condition due to statistical variation of the signal processing described in ETSI

EG 202 396-2 [i.2] leading to non consistent judgements within this condition.

4) Inconsistencies due to Recommendation ITU-T P.56 [i.22] level adjustment process chosen for the complete

files including the background noise.

As a result of the experts listening test a set of data was selected which is used for the development of the objective

model.

In the selection process five expert listeners (non-native French speakers) were involved. Their task was not to produce

new judgements, but to check all the samples in the database with respect to the possible artefacts described above.

A playback system with calibrated headphones was used for the test. The headphones used were Sennheiser HD 600

connected to the HEAD acoustics playback system PEQ V. The equalization provided by the headphone manufacturer

was used since this was the one used in the auditory French test setup.

All samples could be heard by the experts as often as required in order to get final agreement about the applicability of

the data within the terms of reference of the model. There was no limitation in comparing samples to the ones

previously heard.
5.2 Results

In general it could be observed that the 4 seconds sample size chosen in the experiment according to Recommendation

ITU-T P.835 [i.3] lead to a more difficult task even for expert listeners, especially in the case of non-stationary

background noises. It is more difficult to identify the nature of the no
...

Final draft ETSI EG 202 396-3 V1.5.1 (2015-08)
ETSI GUIDE
Speech and multimedia Transmission Quality (STQ);
Speech Quality performance
in the presence of background noise;
Part 3: Background noise transmission -
Objective test methods
---------------------- Page: 1 ----------------------
2 Final draft ETSI EG 202 396-3 V1.5.1 (2015-08)
Reference
REG/STQ-229
Keywords
noise, QoS, quality, speech
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 à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88
Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search

The present document may be made available in electronic versions and/or in print. The content of any electronic and/or

print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any

existing or perceived difference in contents between such versions and/or in print, the only prevailing document is the

print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat.

Users of the present document should be aware that the document may be subject to revision or change of status.

Information on the current status of this and other ETSI documents is available at

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If you find errors in the present document, please send your comment to one of the following services:

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Copyright Notification

No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying

and microfilm except as authorized by written permission of ETSI.

The content of the PDF version shall not be modified without the written authorization of ETSI.

The copyright and the foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 2015.
All rights reserved.
TM TM TM

DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.

3GPP 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
---------------------- Page: 2 ----------------------
3 Final draft ETSI EG 202 396-3 V1.5.1 (2015-08)
Contents

Intellectual Property Rights ................................................................................................................................ 5

Foreword ............................................................................................................................................................. 5

Modal verbs terminology .................................................................................................................................... 5

1 Scope ........................................................................................................................................................ 6

2 References ................................................................................................................................................ 6

2.1 Normative references ......................................................................................................................................... 6

2.2 Informative references ........................................................................................................................................ 7

3 Symbols and abbreviations ....................................................................................................................... 8

3.1 Symbols .............................................................................................................................................................. 8

3.2 Abbreviations ..................................................................................................................................................... 8

4 Speech signals to be used ......................................................................................................................... 9

5 Selection of the data within the scope of the wideband objective model: Experts evaluation ............... 10

5.1 Selection process .............................................................................................................................................. 10

5.2 Results .............................................................................................................................................................. 10

5.3 French database ................................................................................................................................................ 11

6 Description of the wideband objective test method ............................................................................... 11

6.1 Introduction ...................................................................................................................................................... 11

6.2 Speech sample preparation and nomenclature .................................................................................................. 12

6.2.1 Speech sample preparation ......................................................................................................................... 12

6.2.2 Nomenclature .............................................................................................................................................. 14

6.3 Additional Training data .................................................................................................................................. 15

6.4 Principles of Relative Approach and Δ Relative Approach .............................................................................. 15

6.5 Objective N-MOS............................................................................................................................................. 19

6.5.1 Introduction................................................................................................................................................. 19

6.5.2 Description of N-MOS algorithm ............................................................................................................... 19

6.5.3 Comparing subjective and objective N-MOS results .................................................................................. 22

6.6 Objective S-MOS ............................................................................................................................................. 23

6.6.1 Introduction................................................................................................................................................. 23

6.6.2 Description of S-MOS Algorithm ............................................................................................................... 24

6.6.3 Comparing Subjective and Objective S-MOS Results ................................................................................ 27

6.7 Objective G-MOS............................................................................................................................................. 28

6.7.1 Description of G-MOS Algorithm .............................................................................................................. 28

6.7.2 Comparing subjective and objective G-MOS results .................................................................................. 29

7 Validation of the Wideband Objective Test Method .............................................................................. 30

7.1 Introduction ...................................................................................................................................................... 30

7.2 ETSI EG 202 396-2 Database Results Analysis ............................................................................................... 32

7.2.1 Comparing subjective and objective N-MOS results .................................................................................. 32

7.2.2 Comparing subjective and objective S-MOS results .................................................................................. 32

7.2.3 Comparing Subjective and Objective G-MOS Results ............................................................................... 33

7.3 Orange Validation Database results Analysed ................................................................................................. 34

7.3.0 Introduction................................................................................................................................................. 34

7.3.1 Comparing subjective and objective N-MOS results .................................................................................. 34

7.3.2 Comparing subjective and objective S-MOS results .................................................................................. 35

7.3.3 Comparing Subjective and Objective G-MOS Results ............................................................................... 35

8 Objective Model for Narrowband Applications ..................................................................................... 36

8.0 Introduction ...................................................................................................................................................... 36

8.1 File pre-processing ........................................................................................................................................... 36

8.2 Adaptation of the Calculations ......................................................................................................................... 37

8.3 Prediction results .............................................................................................................................................. 39

Annex A: Detailed post evaluation of listening test results ................................................................ 41

Annex B: Results of PESQ and TOSQA2001 - Analysis of ETSI EG 202 396-2 database .............. 44

ETSI
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4 Final draft ETSI EG 202 396-3 V1.5.1 (2015-08)

Annex C: Comparison of objective MOS versus auditory MOS for the complete STF 294

database ................................................................................................................................. 51

Annex D: Comparison of objective MOS versus auditory MOS for rejected conditions ................ 53

Annex E: Void ........................................................................................................................................ 55

Annex F: Detailed STF 294 subjective and objective validation test results .................................... 56

Annex G: Void ........................................................................................................................................ 59

Annex H: Extension of the Speech Quality Test Method to Narrowband: Adaptation,

Training and Validation ....................................................................................................... 60

Annex I: Void ........................................................................................................................................ 62

Annex J: Summary of Czech samples not used for model training .................................................. 63

J.0 Introduction ...................................................................................................................................................... 63

J.1 Selection process - Czech database ........................................................................................................ 63

J.2 General differences between the databases ............................................................................................ 65

J.3 Comparison of the objective method results for Czech and French samples ......................................... 68

J.4 Czech conditions results analysis ........................................................................................................... 73

J.4.1 Comparing subjective and objective N-MOS results ....................................................................................... 73

J.4.2 Comparing subjective and objective S-MOS results ........................................................................................ 73

J.4.3 Comparing Subjective and Objective G-MOS Results..................................................................................... 74

J.5 Language Dependent Robustness of G-MOS......................................................................................... 75

J.6 Regression Coefficients for Czech data ................................................................................................. 76

J.7 Post selection .......................................................................................................................................... 77

Annex K: Relative Approach Non-Linear Transformation ............................................................... 81

Annex L: Bibliography .......................................................................................................................... 82

History .............................................................................................................................................................. 83

ETSI
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5 Final draft ETSI EG 202 396-3 V1.5.1 (2015-08)
Intellectual 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 000 314: "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 updates are available on the ETSI Web

server (http://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

server) which are, or may be, or may become, essential to the present document.
Foreword

This final draft ETSI Guide (EG) has been produced by ETSI Technical Committee Speech and multimedia

Transmission Quality (STQ), and is now submitted for the ETSI standards Membership Approval Procedure.

The present document is a deliverable of ETSI Specialized Task Force (STF) 294 entitled: "Improving the quality of

eEurope wideband speech applications by developing a performance testing and evaluation methodology for

background noise transmission".

The present document is part 3 of a multi-part deliverable covering Speech and multimedia Transmission Quality

(STQ); Speech Quality performance in the presence of background noise, as identified below:

Part 1: "Background noise simulation technique and background noise database";

Part 2: "Background noise transmission - Network simulation - Subjective test database and results";

Part 3: "Background noise transmission - Objective test methods".
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 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
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6 Final draft ETSI EG 202 396-3 V1.5.1 (2015-08)
1 Scope

The present document aims to identify and define testing methodologies which can be used to objectively evaluate the

performance of narrowband and wideband terminals and systems for speech communication in the presence of

background noise.

Background noise is a problem in mostly all situations and conditions and need to be taken into account in both,

terminals and networks. The present document provides information about the testing methods applicable to objectively

evaluate the speech quality in the presence of background noise. The present document includes:

• The description of the experts post evaluation process chosen to select the subjective test data being within the

scope of the objective methods.

• The results of the performance evaluation of the currently existing methods described in Recommendations

ITU-T P.862 [i.16], Recommendation ITU-T P.862.1 [i.17] and in TOSQA2001 [i.19] which is chosen for the

evaluation of terminals in the framework of ETSI VoIP speech quality test events [i.8], [i.9], [i.10] and [i.11].

• The method which is applicable to objectively determine the different parameters influencing the speech

quality in the presence of background noise taking into account:
- the speech quality;
- the background noise transmission quality;
- the overall quality.
• The present document is to be used in conjunction with:

- ETSI ES 202 396-1 [i.1] which describes a recording and reproduction setup for realistic simulation of

background noise scenarios in lab-type environments for the performance evaluation of terminals and

communication systems.

- ETSI EG 202 396-2 [i.2] which describes the simulation of network impairments and how to simulate

realistic transmission network scenarios and which contains the methodology and results of the

subjective scoring for the data forming the basis of the present document.

- French speech sentences as defined in Recommendation ITU-T P.501 [i.13] for wideband and English

speech sentences as defined in Recommendation ITU-T P.501 [i.13] for narrowband.
2 References
2.1 Normative references

References are either specific (identified by date of publication and/or edition number or version number) or

non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the

reference document (including any amendments) applies.

Referenced documents which are not found to be publicly available in the expected location might be found at

http://docbox.etsi.org/Reference.

NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee

their long term validity.

The following referenced documents are necessary for the application of the present document.

Not applicable.
ETSI
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7 Final draft ETSI EG 202 396-3 V1.5.1 (2015-08)
2.2 Informative references

References are either specific (identified by date of publication and/or edition number or version number) or

non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the

reference document (including any amendments) applies.

NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee

their long term validity.

The following referenced documents are not necessary for the application of the present document but they assist the

user with regard to a particular subject area.

[i.1] ETSI ES 202 396-1: "Speech and multimedia Transmission Quality (STQ); Speech quality

performance in the presence of background noise; Part 1: Background noise simulation technique

and background noise database".

[i.2] ETSI EG 202 396-2: "Speech Processing, Transmission and Quality Aspects (STQ); Speech

Quality performance in the presence of background noise; Part 2: Background Noise Transmission

- Network Simulation - Subjective Test Database and Results".

[i.3] Recommendation ITU-T P.835: "Subjective test methodology for evaluating speech

communication systems that include noise suppression algorithm".

[i.4] Recommendation ITU-T P.800: "Methods for subjective determination of transmission quality".

[i.5] Recommendation ITU-T P.831: "Subjective performance evaluation of network echo cancellers".

[i.6] Genuit, K.: "Objective Evaluation of Acoustic Quality Based on a Relative Approach",

InterNoise '96, Liverpool, UK.

[i.7] Recommendation ITU-T SG 12 Contribution 34: "Evaluation of the quality of background noise

transmission using the "Relative Approach"".

[i.8] ETSI 2 Speech Quality Test Event: "Anonymized Test Report", ETSI Plugtests, HEAD

acoustics, T-Systems Nova.

NOTE: Available at: http://www.etsi.org/WebSite/OurServices/Plugtests/History.aspx. Also available as ETSI

TR 102 648-3.
[i.9] ETSI 3 Speech Quality Test Event: "Anonymized Test Report "IP Gateways".

NOTE: Available at: http://www.etsi.org/WebSite/OurServices/Plugtests/History.aspx.

[i.10] ETSI 3 Speech Quality Test Event: "Anonymized Test Report "IP Phones".

[i.11] ETSI 4 Speech Quality Test Event: "Anonymized Test Report "IP Gateways and IP Phones".

NOTE: Available at: http://www.etsi.org/WebSite/OurServices/Plugtests/History.aspx.

[i.12] F. Kettler, H.W. Gierlich, F. Rosenberger: "Application of the Relative Approach to Optimize

Packet Loss Concealment Implementations", DAGA, March 2003, Aachen, Germany.
[i.13] Recommendation ITU-T P.501: "Test Signals for Use in Telephonometry".

[i.14] R. Sottek, K. Genuit: "Models of Signal Processing in human hearing", International Journal of

Electronics and Communications (AEÜ) volume 59, 2005, p. 157-165.
NOTE: Available at: http://www.elsevier.de/aeue.

[i.15] SAE International - Document 2005-01-2513: "Tools and Methods for Product Sound Design of

Vehicles" R. Sottek, W. Krebber, G. Stanley.

[i.16] Recommendation ITU-T P.862: "Perceptual evaluation of speech quality (PESQ): An objective

method for end-to-end speech quality assessment of narrowband telephone networks and speech

codecs".
ETSI
---------------------- Page: 7 ----------------------
8 Final draft ETSI EG 202 396-3 V1.5.1 (2015-08)

[i.17] Recommendation ITU-T P.862.1: "Mapping function for transforming P.862 raw result scores to

MOS-LQO".

[i.18] Recommendation ITU-T P.862.2: "Wideband extension to Recommendation P.862 for the

assessment of wideband telephone networks and speech codecs".

[i.19] Recommendation ITU-T SG 12 Contribution 19: "Results of objective speech quality assessment

of wideband speech using the Advanced TOSQA2001".
[i.20] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".

[i.21] Recommendation ITU-T G.722.2: "Wideband coding of speech at around 16 kbit/s using Adaptive

Multi-Rate Wideband (AMR-WB)".

[i.22] Recommendation ITU-T P.56: "Objective measurement of active speech level".

[i.23] Recommendation ITU-T P.57: "Artificial ears".
[i.24] M. Spiegel: "Theory and problems of statistics", McGraw Hill, 1998.
[i.25] Void.

[i.26] M. Kendall: "Rank correlation methods", Charles Griffin & Company Limited, 1948.

[i.27] Sottek, R.: "Modelle zur Signalverarbeitung im menschlichen Gehör", PHD thesis RWTH Aachen,

1993.

[i.28] Recommendation ITU-T P.830: "Subjective performance assessment of telephone-band and

wideband digital codecs".
[i.29] Void.

[i.30] ANSI S1.1-1986 (ASA 65-1986): "Specifications for Octave-Band and Fractional-Octave-Band

Analog and Digital Filters", 1993.

[i.31] Recommendation ITU-T G.160 Appendix II, Amendment 2: "Voice enhancement devices:

Revised Appendix II - Objective measures for the characterization of the basic functioning of

noise reduction algorithms".

[i.32] ETSI TS 103 106: "Speech and multimedia Transmission Quality (STQ); Speech quality

performance in the presence of background noise: Background noise transmission for mobile

terminals-objective test methods".

[i.33] Hastie, T.; Tibshirani, R.; Friedman, J.: "The Elements of Statistical Learning: Data Mining,

Inference, and Prediction", New York: Springer-Verlag, 2001.
3 Symbols and abbreviations
3.1 Symbols
For the purposes of the present document, the following symbols apply:
σ Variance
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AMR Adaptive MultiRate
ASL Active Speech Level
NOTE: According to Recommendation ITU-T P.56 [i.22].
ETSI
---------------------- Page: 8 ----------------------
9 Final draft ETSI EG 202 396-3 V1.5.1 (2015-08)
BGN BackGround Noise
CDF Cumulative Density Function
dB SPL Sound Pressure Level re 20 µPa in dB
DB Data Base
DUT Device Under Test
EFR Enhance Full Rate
FR Full Rate
G-MOS Global MOS
NOTE: MOS related to the overall sample.
GSM Global System for Mobile Communication
HATS Head And Torso Simulator
IP Internet Protocol
IRS Intermediate Reference System
ITU International Telecommunication Union
ITU-T Telecom Standardization Body of ITU
MMSE Minimum Mean Square Error
MOS Mean Opinion Score
MOS-LQSN Mean Opinion Score - Listening Quality Subjective Noise
MRP Mouth Reference Point
NB NarrowBand
NI Network I conditions
NII Network II conditions
NIII Network III conditions
N-MOS Noise MOS
NOTE: MOS related to the noise transmission only.
NR Noise Reduction
NR (filter) Noise Reduction (filter)
NSA Noise Suppression Algorithm
PESQ Perceptual Evaluation of Speech Quality
PLC Packet Loss Concealment
RCV ReCeiVe
RMS Root Mean Square
RMSE Random Mean Square Error
S-MOS Speech MOS
NOTE: MOS related to the speech signal only.
SND Sending Direction
SNR Signal to Noise Ratio
SQTE Speech Quality Test Event
SPL Sound Pressure Level
STD STandard Deviation
STF Specialized Task Force
TMOS TOSQA Mean Opinion Score
TOR Terms Of Reference
VAD Voice Activity Detection
VoIP Voice over IP
WB WideBand
4 Speech signals to be used

As with any objective model, the prediction of speech quality depends on the conditions under which the model was

tested and validated (see clauses 6.1 and 8). This dependency also applies to the speech material used in conjunction

with the objective model.

The wideband version of the model uses French speech sentences. The near end speech signal (clean speech signal)

consists of 8 sentences of speech (2 male and 2 female talkers, 2 sentences each). Appropriate speech samples can be

taken from Recommendation ITU-T P.501 [i.13].
ETSI
---------------------- Page: 9 ----------------------
10 Final draft ETSI EG 202 396-3 V1.5.1 (2015-08)

The narrowband version of the model uses English speech sentences. The near end speech signal (clean speech signal)

consists of 8 sentences of speech (2 male and 2 female talkers, 2 sentences each). Appropriate speech samples can be

taken from Recommendation ITU-T P.501 [i.13].
5 Selection of the data within the scope of the
wideband objective model: Experts evaluation
5.1 Selection process

The aim of the selection process was to identify those data in the databases described in ETSI EG 202 396-2 [i.2] which

are consistent with the scope of the objective models to be studied within the present document.

The experts were selected on the based on the definition found in e.g. Recommendation ITU-T P.831 [i.5]: experts are

experienced in subjective testing. Experts are able to describe an auditory event in detail and are able to separate

different events based on specific impairments. They are able to describe their subjective impressions in detail. They

have a background in technical implementations of noise reduction systems and transmission impairments and do have

detailed knowledge of the influence of particular implementations on subjective quality.

Their task was to select the relevant conditions within the scope of the model to be developed. Therefore they had to

verify the consistency of the data with respect to the following selection criteria:

1) Artefacts others than the ones which should have been produced by the signal processing described in ETSI

EG 202 396-2 [i.2] e.g. due to the additional amplification required in order to provide a listening level of

79 dB SPL.

2) Inconsistencies within one condition due to the selection of the individual speech samples from the database

for subjective evaluation.

3) Inconsistencies within one condition due to statistical variation of the signal processing described in ETSI

EG 202 396-2 [i.2] leading to non consistent judgements within this condition.

4) Inconsistencies due to Recommendation ITU-T P.56 [i.22] level adjustment process chosen for the complete

files including the background noise.

As a result of the experts listening test a set of data was selected which is used for the development of the objective

model.

In the selection process five expert listeners (non-native French speakers) were involved. Their task was not to produce

new judgements, but to check all the samples in the database with respect to the possible artefacts described above.

A playback system with calibrated headphones was used for the test. The headphones used were Sennheiser HD 600

connected to the HEAD acoustics playback system PEQ V. The equalization provided by the headphone manufacturer

was used since this was the one used in the auditory French test setup.

All samples could be heard by the experts as often as required in order to get final agreement about the applicability of

the data within the terms of reference of the model. There was no limitation in comparing samples to the ones

previously heard.
5.2 Results
In general it could be observed that the 4 seconds sample size chosen in the exp
...

SLOVENSKI STANDARD
SIST-V ETSI/EG 202 396-3 V1.5.1:2016
01-februar-2016
.DNRYRVWSUHQRVDJRYRUDLQYHþSUHGVWDYQLKYVHELQ 674 =PRJOMLYRVWNDNRYRVWL
JRYRUDYSULVRWQRVWLãXPDR]DGMDGHO3UHQRVãXPDR]DGMD2EMHNWLYQH
SUHVNXVQHPHWRGH

Speech and multimedia Transmission Quality (STQ) - Speech Quality performance in the

presence of background noise - Part 3: Background noise transmission - Objective test

methods
Ta slovenski standard je istoveten z: EG 202 396-3 V1.5.1
ICS:
33.040.35 Telefonska omrežja Telephone networks
SIST-V ETSI/EG 202 396-3 V1.5.1:2016 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST-V ETSI/EG 202 396-3 V1.5.1:2016
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SIST-V ETSI/EG 202 396-3 V1.5.1:2016
ETSI EG 202 396-3 V1.5.1 (2015-10)
ETSI GUIDE
Speech and multimedia Transmission Quality (STQ);
Speech Quality performance
in the presence of background noise;
Part 3: Background noise transmission -
Objective test methods
---------------------- Page: 3 ----------------------
SIST-V ETSI/EG 202 396-3 V1.5.1:2016
2 ETSI EG 202 396-3 V1.5.1 (2015-10)
Reference
REG/STQ-229
Keywords
noise, QoS, quality, speech
ETSI
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Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search

The present document may be made available in electronic versions and/or in print. The content of any electronic and/or

print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any

existing or perceived difference in contents between such versions and/or in print, the only prevailing document is the

print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat.

Users of the present document should be aware that the document may be subject to revision or change of status.

Information on the current status of this and other ETSI documents is available at

http://portal.etsi.org/tb/status/status.asp

If you find errors in the present document, please send your comment to one of the following services:

https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Copyright Notification

No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying

and microfilm except as authorized by written permission of ETSI.

The content of the PDF version shall not be modified without the written authorization of ETSI.

The copyright and the foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 2015.
All rights reserved.
TM TM TM

DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.

3GPP 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
---------------------- Page: 4 ----------------------
SIST-V ETSI/EG 202 396-3 V1.5.1:2016
3 ETSI EG 202 396-3 V1.5.1 (2015-10)
Contents

Intellectual Property Rights ................................................................................................................................ 5

Foreword ............................................................................................................................................................. 5

Modal verbs terminology .................................................................................................................................... 5

1 Scope ........................................................................................................................................................ 6

2 References ................................................................................................................................................ 6

2.1 Normative references ......................................................................................................................................... 6

2.2 Informative references ........................................................................................................................................ 7

3 Symbols and abbreviations ....................................................................................................................... 8

3.1 Symbols .............................................................................................................................................................. 8

3.2 Abbreviations ..................................................................................................................................................... 8

4 Speech signals to be used ......................................................................................................................... 9

5 Selection of the data within the scope of the wideband objective model: Experts evaluation ............... 10

5.1 Selection process .............................................................................................................................................. 10

5.2 Results .............................................................................................................................................................. 10

5.3 French database ................................................................................................................................................ 11

6 Description of the wideband objective test method ............................................................................... 11

6.1 Introduction ...................................................................................................................................................... 11

6.2 Speech sample preparation and nomenclature .................................................................................................. 12

6.2.1 Speech sample preparation ......................................................................................................................... 12

6.2.2 Nomenclature .............................................................................................................................................. 14

6.3 Additional Training data .................................................................................................................................. 15

6.4 Principles of Relative Approach and Δ Relative Approach .............................................................................. 15

6.5 Objective N-MOS............................................................................................................................................. 19

6.5.1 Introduction................................................................................................................................................. 19

6.5.2 Description of N-MOS algorithm ............................................................................................................... 19

6.5.3 Comparing subjective and objective N-MOS results .................................................................................. 22

6.6 Objective S-MOS ............................................................................................................................................. 23

6.6.1 Introduction................................................................................................................................................. 23

6.6.2 Description of S-MOS Algorithm ............................................................................................................... 24

6.6.3 Comparing Subjective and Objective S-MOS Results ................................................................................ 27

6.7 Objective G-MOS............................................................................................................................................. 28

6.7.1 Description of G-MOS Algorithm .............................................................................................................. 28

6.7.2 Comparing subjective and objective G-MOS results .................................................................................. 29

7 Validation of the Wideband Objective Test Method .............................................................................. 30

7.1 Introduction ...................................................................................................................................................... 30

7.2 ETSI EG 202 396-2 Database Results Analysis ............................................................................................... 32

7.2.1 Comparing subjective and objective N-MOS results .................................................................................. 32

7.2.2 Comparing subjective and objective S-MOS results .................................................................................. 32

7.2.3 Comparing Subjective and Objective G-MOS Results ............................................................................... 33

7.3 Orange Validation Database results Analysed ................................................................................................. 34

7.3.0 Introduction................................................................................................................................................. 34

7.3.1 Comparing subjective and objective N-MOS results .................................................................................. 34

7.3.2 Comparing subjective and objective S-MOS results .................................................................................. 35

7.3.3 Comparing Subjective and Objective G-MOS Results ............................................................................... 35

8 Objective Model for Narrowband Applications ..................................................................................... 36

8.0 Introduction ...................................................................................................................................................... 36

8.1 File pre-processing ........................................................................................................................................... 36

8.2 Adaptation of the Calculations ......................................................................................................................... 37

8.3 Prediction results .............................................................................................................................................. 38

Annex A: Detailed post evaluation of listening test results ................................................................ 40

Annex B: Results of PESQ and TOSQA2001 - Analysis of ETSI EG 202 396-2 database .............. 43

ETSI
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SIST-V ETSI/EG 202 396-3 V1.5.1:2016
4 ETSI EG 202 396-3 V1.5.1 (2015-10)

Annex C: Comparison of objective MOS versus auditory MOS for the complete STF 294

database ................................................................................................................................. 50

Annex D: Comparison of objective MOS versus auditory MOS for rejected conditions ................ 52

Annex E: Void ........................................................................................................................................ 54

Annex F: Detailed STF 294 subjective and objective validation test results .................................... 55

Annex G: Void ........................................................................................................................................ 58

Annex H: Extension of the Speech Quality Test Method to Narrowband: Adaptation,

Training and Validation ....................................................................................................... 59

Annex I: Void ........................................................................................................................................ 61

Annex J: Summary of Czech samples not used for model training .................................................. 62

J.0 Introduction ...................................................................................................................................................... 62

J.1 Selection process - Czech database ........................................................................................................ 62

J.2 General differences between the databases ............................................................................................ 64

J.3 Comparison of the objective method results for Czech and French samples ......................................... 67

J.4 Czech conditions results analysis ........................................................................................................... 72

J.4.1 Comparing subjective and objective N-MOS results ....................................................................................... 72

J.4.2 Comparing subjective and objective S-MOS results ........................................................................................ 72

J.4.3 Comparing Subjective and Objective G-MOS Results..................................................................................... 73

J.5 Language Dependent Robustness of G-MOS......................................................................................... 74

J.6 Regression Coefficients for Czech data ................................................................................................. 75

J.7 Post selection .......................................................................................................................................... 76

Annex K: Relative Approach Non-Linear Transformation ............................................................... 80

Annex L: Bibliography .......................................................................................................................... 81

History .............................................................................................................................................................. 82

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Intellectual 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 000 314: "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 updates are available on the ETSI Web

server (http://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

server) which are, or may be, or may become, essential to the present document.
Foreword

This ETSI Guide (EG) has been produced by ETSI Technical Committee Speech and multimedia Transmission Quality

(STQ).

The present document is a deliverable of ETSI Specialized Task Force (STF) 294 entitled: "Improving the quality of

eEurope wideband speech applications by developing a performance testing and evaluation methodology for

background noise transmission".

The present document is part 3 of a multi-part deliverable covering Speech and multimedia Transmission Quality

(STQ); Speech Quality performance in the presence of background noise, as identified below:

Part 1: "Background noise simulation technique and background noise database";

Part 2: "Background noise transmission - Network simulation - Subjective test database and results";

Part 3: "Background noise transmission - Objective test methods".
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 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.

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1 Scope

The present document aims to identify and define testing methodologies which can be used to objectively evaluate the

performance of narrowband and wideband terminals and systems for speech communication in the presence of

background noise.

Background noise is a problem in mostly all situations and conditions and need to be taken into account in both,

terminals and networks. The present document provides information about the testing methods applicable to objectively

evaluate the speech quality in the presence of background noise. The present document includes:

• The description of the experts post evaluation process chosen to select the subjective test data being within the

scope of the objective methods.

• The results of the performance evaluation of the currently existing methods described in Recommendations

ITU-T P.862 [i.16] and P.862.1 [i.17] and in TOSQA2001 [i.19] which is chosen for the evaluation of

terminals in the framework of ETSI VoIP speech quality test events [i.8], [i.9], [i.10] and [i.11].

• The method which is applicable to objectively determine the different parameters influencing the speech

quality in the presence of background noise taking into account:
- the speech quality;
- the background noise transmission quality;
- the overall quality.
• The present document is to be used in conjunction with:

- ETSI ES 202 396-1 [i.1] which describes a recording and reproduction setup for realistic simulation of

background noise scenarios in lab-type environments for the performance evaluation of terminals and

communication systems.

- ETSI EG 202 396-2 [i.2] which describes the simulation of network impairments and how to simulate

realistic transmission network scenarios and which contains the methodology and results of the

subjective scoring for the data forming the basis of the present document.

- French speech sentences as defined in Recommendation ITU-T P.501 [i.13] for wideband and English

speech sentences as defined in Recommendation ITU-T P.501 [i.13] for narrowband.
2 References
2.1 Normative references

References are either specific (identified by date of publication and/or edition number or version number) or

non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the

reference document (including any amendments) applies.

Referenced documents which are not found to be publicly available in the expected location might be found at

http://docbox.etsi.org/Reference.

NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee

their long term validity.

The following referenced documents are necessary for the application of the present document.

Not applicable.
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2.2 Informative references

References are either specific (identified by date of publication and/or edition number or version number) or

non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the

reference document (including any amendments) applies.

NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee

their long term validity.

The following referenced documents are not necessary for the application of the present document but they assist the

user with regard to a particular subject area.

[i.1] ETSI ES 202 396-1: "Speech and multimedia Transmission Quality (STQ); Speech quality

performance in the presence of background noise; Part 1: Background noise simulation technique

and background noise database".

[i.2] ETSI EG 202 396-2: "Speech Processing, Transmission and Quality Aspects (STQ); Speech

Quality performance in the presence of background noise; Part 2: Background Noise Transmission

- Network Simulation - Subjective Test Database and Results".

[i.3] Recommendation ITU-T P.835: "Subjective test methodology for evaluating speech

communication systems that include noise suppression algorithm".

[i.4] Recommendation ITU-T P.800: "Methods for subjective determination of transmission quality".

[i.5] Recommendation ITU-T P.831: "Subjective performance evaluation of network echo cancellers".

[i.6] Genuit, K.: "Objective Evaluation of Acoustic Quality Based on a Relative Approach",

InterNoise '96, Liverpool, UK.

[i.7] Recommendation ITU-T SG 12 Contribution 34: "Evaluation of the quality of background noise

transmission using the "Relative Approach"".

[i.8] ETSI 2 Speech Quality Test Event: "Anonymized Test Report", ETSI Plugtests, HEAD

acoustics, T-Systems Nova.

NOTE: Available at: http://www.etsi.org/WebSite/OurServices/Plugtests/History.aspx. Also available as ETSI

TR 102 648-3.
[i.9] ETSI 3 Speech Quality Test Event: "Anonymized Test Report "IP Gateways".

NOTE: Available at: http://www.etsi.org/WebSite/OurServices/Plugtests/History.aspx.

[i.10] ETSI 3 Speech Quality Test Event: "Anonymized Test Report "IP Phones".

[i.11] ETSI 4 Speech Quality Test Event: "Anonymized Test Report "IP Gateways and IP Phones".

NOTE: Available at: http://www.etsi.org/WebSite/OurServices/Plugtests/History.aspx.

[i.12] F. Kettler, H.W. Gierlich, F. Rosenberger: "Application of the Relative Approach to Optimize

Packet Loss Concealment Implementations", DAGA, March 2003, Aachen, Germany.
[i.13] Recommendation ITU-T P.501: "Test Signals for Use in Telephonometry".

[i.14] R. Sottek, K. Genuit: "Models of Signal Processing in human hearing", International Journal of

Electronics and Communications (AEÜ) volume 59, 2005, p. 157-165.
NOTE: Available at: http://www.elsevier.de/aeue.

[i.15] SAE International - Document 2005-01-2513: "Tools and Methods for Product Sound Design of

Vehicles" R. Sottek, W. Krebber, G. Stanley.

[i.16] Recommendation ITU-T P.862: "Perceptual evaluation of speech quality (PESQ): An objective

method for end-to-end speech quality assessment of narrowband telephone networks and speech

codecs".
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[i.17] Recommendation ITU-T P.862.1: "Mapping function for transforming P.862 raw result scores to

MOS-LQO".

[i.18] Recommendation ITU-T P.862.2: "Wideband extension to Recommendation P.862 for the

assessment of wideband telephone networks and speech codecs".

[i.19] Recommendation ITU-T SG 12 Contribution 19: "Results of objective speech quality assessment

of wideband speech using the Advanced TOSQA2001".
[i.20] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".

[i.21] Recommendation ITU-T G.722.2: "Wideband coding of speech at around 16 kbit/s using Adaptive

Multi-Rate Wideband (AMR-WB)".

[i.22] Recommendation ITU-T P.56: "Objective measurement of active speech level".

[i.23] Recommendation ITU-T P.57: "Artificial ears".
[i.24] M. Spiegel: "Theory and problems of statistics", McGraw Hill, 1998.
[i.25] Void.

[i.26] M. Kendall: "Rank correlation methods", Charles Griffin & Company Limited, 1948.

[i.27] Sottek, R.: "Modelle zur Signalverarbeitung im menschlichen Gehör", PHD thesis RWTH Aachen,

1993.

[i.28] Recommendation ITU-T P.830: "Subjective performance assessment of telephone-band and

wideband digital codecs".
[i.29] Void.

[i.30] ANSI S1.1-1986 (ASA 65-1986): "Specifications for Octave-Band and Fractional-Octave-Band

Analog and Digital Filters", 1993.

[i.31] Recommendation ITU-T G.160 Appendix II, Amendment 2: "Voice enhancement devices:

Revised Appendix II - Objective measures for the characterization of the basic functioning of

noise reduction algorithms".

[i.32] ETSI TS 103 106: "Speech and multimedia Transmission Quality (STQ); Speech quality

performance in the presence of background noise: Background noise transmission for mobile

terminals-objective test methods".

[i.33] Hastie, T.; Tibshirani, R.; Friedman, J.: "The Elements of Statistical Learning: Data Mining,

Inference, and Prediction", New York: Springer-Verlag, 2001.
3 Symbols and abbreviations
3.1 Symbols
For the purposes of the present document, the following symbols apply:
σ Variance
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AMR Adaptive MultiRate
ASL Active Speech Level
NOTE: According to Recommendation ITU-T P.56 [i.22].
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BGN BackGround Noise
CDF Cumulative Density Function
dB SPL Sound Pressure Level re 20 µPa in dB
DB Data Base
DUT Device Under Test
EFR Enhance Full Rate
FR Full Rate
G-MOS Global MOS
NOTE: MOS related to the overall sample.
GSM Global System for Mobile Communication
HATS Head And Torso Simulator
IP Internet Protocol
IRS Intermediate Reference System
ITU International Telecommunication Union
ITU-T Telecom Standardization Body of ITU
MMSE Minimum Mean Square Error
MOS Mean Opinion Score
MOS-LQSN Mean Opinion Score - Listening Quality Subjective Noise
MRP Mouth Reference Point
NB NarrowBand
NI Network I conditions
NII Network II conditions
NIII Network III conditions
N-MOS Noise MOS
NOTE: MOS related to the noise transmission only.
NR Noise Reduction
NR (filter) Noise Reduction (filter)
NSA Noise Suppression Algorithm
PESQ Perceptual Evaluation of Speech Quality
PLC Packet Loss Concealment
RCV ReCeiVe
RMS Root Mean Square
RMSE Random Mean Square Error
S-MOS Speech MOS
NOTE: MOS related to the speech signal only.
SND Sending Direction
SNR Signal to Noise Ratio
SQTE Speech Quality Test Event
SPL Sound Pressure Level
STD STandard Deviation
STF Specialized Task Force
TMOS TOSQA Mean Opinion Score
TOR Terms Of Reference
VAD Voice Activity Detection
VoIP Voice over IP
WB WideBand
4 Speech signals to be used

As with any objective model, the prediction of speech quality depends on the conditions under which the model was

tested and validated (see clauses 6.1 and 8). This dependency also applies to the speech material used in conjunction

with the objective model.

The wideband version of the model uses French speech sentences. The near end speech signal (clean speech signal)

consists of 8 sentences of speech (2 male and 2 female talkers, 2 sentences each). Appropriate speech samples can be

taken from Recommendation ITU-T P.501 [i.13].
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The narrowband version of the model uses English speech sentences. The near end speech signal (clean speech signal)

consists of 8 sentences of speech (2 male and 2 female talkers, 2 sentences each). Appropriate speech samples can be

taken from Recommendation ITU-T P.501 [i.13].
5 Selection of the data within the scope of the
wideband objective model: Experts evaluation
5.1 Selection process

The aim of the selection process was to identify those data in the databases described in ETSI EG 202 396-2 [i.2] which

are consistent with the scope of the objective models to be studied within the present document.

The experts were selected on the based on the definition found in e.g. Recommendation ITU-T P.831 [i.5]: experts are

experienced in subjective testing. Experts are able to describe an auditory event in detail and are able to separate

different events based on specific impairments. They are able to describe their subjective impressions in detail. They

have a background in technical implementations of noise reduction systems and transmission impairments and do have

detailed knowledge of the influence of particular implementations on subjective quality.

Their task was to select the relevant conditions within the scope of the model to be developed. Therefore they had to

verify the consistency of the data with respect to the following selection criteria:

1) Artefacts others than the ones which should have been produced by the signal processing described in ETSI

EG 202 396-2 [i.2] e.g. due to the additional amplification required in order to provide a listening level of

79 dB SPL.

2) Inconsistencies within one condition due to the selection of the individual speech samples from the database

for subjective evaluation.

3) Inconsistencies within one condition due to statistical variation of the signal processing described in ETSI

EG 202 396-2 [i.2] leading to non consistent judgements within this condition.

4) Inconsistencies due to Recommendation ITU-T P.56 [i.22] level adjustment process chosen for the complete

files including the bac
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