1
Scope
2
References
3
Definitions
3.1
Terms defined elsewhere
3.2
Terms defined in this Recommendation
4
Abbreviations and acronyms
5
Conventions
6
Introduction to ITU-T P.863
6.1
History of objective speech quality
6.2
Basics of a subjective test
6.3
Benefit of using Recommendation ITU-T P.863
6.4
Relationship with other Recommendations
6.5
Moving from ITU-T P.862 to ITU-T P.863
6.6
Challenges with ITU-T P.863
6.7
MOS misconceptions
7
Operational modes
7.1
Why two operational modes?
7.2
When should the narrowband mode be used?
7.3
When should the superwideband mode be used?
7.4
Why no wideband (up to 7 kHz) mode?
7.5
Are narrowband signals scored equally in narrowband and superwideband
modes?
7.6
Can I map a narrowband score to a superwideband score?
7.7
Is it recommended to mix bandwidths in subjective testing?
8
Influence of reference speech on scores
8.1
What characteristics should a reference signal contain?
8.2
Are there constraints on the recording environment?
8.3
Can we use artificial speech signals?
8.4
What filter specification should be used?
8.5
Does reference material influence scores?
8.6
How much reference material should I use?
8.7
What is the impact of silence padding?
8.8
How do I validate a reference signal?
8.9
How do I use a 10 minute reference file?
9
How to inject test signals
9.1
Over which interfaces can signals be injected into a network?
9.2
Should the test signal be filtered?
9.3
What level should be used?
10
Influence of recording process on scores
10.1
What influence does file speech level have on score?
10.2
Should we pre-align signal levels?
10.3
Should we apply a filter to the recording?
10.4
Does ITU-T P.863 handle silence padding?
10.5
Can I assess a narrowband recording in superwideband mode?
11
Behaviour of ITU-T P.863
11.1
Global level changes
11.2
Local level changes
11.3
Bandwidth limitations
11.4
Stretching and compressing speech
11.5
Step delay changes
11.6
Long-term gaps in speech
11.7
Short-term gaps in speech
11.8
Cellular handovers
12
Comparison of ITU-T P.862.1/ITU-T P.862.2 and ITU-T P.863
12.1
Scale differences
12.2
Degradation handling differences
12.3
Standard codecs
13
Procedure for comparing subjective test results to ITU-T P.863 results
14
Validation scope
14.1
Validated
14.2
Not yet validated
14.3
Outside scope
Appendix I – ITU-T P.863 Reference validation checks
Appendix II – Typical scores expected from ITU-T P.863 for a given
codec
Appendix III – Applications for further investigation
Bibliography