Rec. ITU-T P.863.1 (06/2019) - Application guide for Recommendation ITU-T P.863
Summary
History
FOREWORD
Table of Contents
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 fullband mode be used?
     7.4 Why no wideband (up to 7 kHz) mode?
     7.5 Are narrowband signals scored equally in narrowband and fullband modes?
     7.6 Can I map a narrowband score to a fullband 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 silence padding affect the ITU-T P.863 scores?
     10.5 Can I assess a narrowband recording in fullband 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
          11.4.1 Uniform time scaling without pitch preservation
          11.4.2 Uniform time scaling with pitch preservation
          11.4.3 Non-uniform time scaling without pitch preservation
          11.4.4 Non-uniform time scaling with pitch preservation
     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 transparency checks of reference files
Appendix II  Typical scores expected from ITU-T P.863 for a given codec
Appendix III  Applications for further investigation
Bibliography