1. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 1 8th and 9th June 2004 - Mainz, Germany Jens Berger SwissQual AG, Switzerland jens.berger@swissqual.com Future work on objective speech quality measurements in ITU-T

2. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 2  History in ITU-T / CCITT  Current Work – Listening Quality  New Aspects in the Coming Study Period of ITU-T Structure

3. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 3 History in ITU-T / CCITT 1981-1984Models for predicting transmission quality from objective measurementsQ7/XII Non-linear distortion of telephone apparatusQ13/XII 1985-1988Models for predicting transmission quality from objective measurementsQ7/XII Non-linear distortion of telephone apparatusQ13/XII 1988-1992Models for predicting transmission quality from objective measurementsQ7/XII Methods for the evaluation of non-linear distortionQ13/XII 1993-1996Methods for measuring and modeling the effects of non-linear processes on the speech quality of transmission systems Q13/XII 1996-2000Objective measurement of speech quality under conditions of non-linear processing Q13/12 1996-2004Objective measurement of speech quality under conditions of non-linear and time varying processing Q9/12 2005-2008Perceptual-based objective methods for voice, audio and visual quality measurements in telecommunication services

4. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 4 Before 1990:  ‘classical’ measurements of transmission / terminal characteristics  early spectral- / cepstral-based measures 1996: P.861 ‘PSQM’  1st psychoacoustic based measure for predicting listening Quality Only ‚Core-Model‘ (no gain-/time-alignment) 2001: P.862 ‘PESQ’  Replaced P.861 Complete method incl. time-/gain-alignement 2004: P.563  1st single ended model for LQ assessments Still Open  Listening Quality for Wideband speech  Listening Quality at Acoustical Interfaces History in ITU-T / CCITT

5. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 5 Main progression within the last few years: Acceptance of psycho-acoustic based measures modelling results of auditory tests on subjective scales but a)Restriction to Listening Quality b)Only applicable on narrow-band voice telephony services c)Serving only ‘electrical’ interfaces Current Focus – Listening Quality

6. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 6 Ongoing activities of former question 9/12  Wide-band speech (listening) quality  Listening quality at acoustical interfaces and extensions to  Audio- and noise-signals over telephone channels  Audio-visual aspects  Talking quality and relations to conversational quality but  Restriction to perceptual based models only Work program starting 2005

7. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 7 Principle concept: Objective measures model specific subjective (auditory) test scenarios and predict their results on a similar scale. Consequence: A subjective test scenario has to be defined and established before the corresponding objective model can be developed. Experience: The better the auditory tests are defined and the stronger their requirements are the more accurate the predicted results will be. Work program starting 2005

8. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 8 Current status:  Proposal from BT and KPN to extend P.862 (COM-12/D180, Feb. 2001)  Several studies from NTT in 2004 analyze pro’s and con’s of this proposal  Awaiting advanced solutions for initial meeting in 2005 Open points:  Corresponding auditory tests (pure wide-band, mixed with narrow band, which ratio?, which terminal(s)?)  What about ‘half-wideband’ (e.g. 200-5000Hz)?  Wider influence on terminal characteristics. Is wide-band speech analysis useful without acoustical interfaces? Wide-band speech scenarios

9. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 9 Current status:  Work item P.AAM currently stopped because disagreement on test scenarios to be served by the approach.  Awaiting precise definitions about the scope and the expected applications of the model Open points:  Corresponding auditory tests for noise at listener side  Handling of handsfree in auditory tests (pure handsfree or mixed with handset)  Handling of different terminals (mix of monotic and diotic, influence of loss of acoustical coupling to real environment?) Acoustical interfaces

10. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 10 Current status:  Proposal from KPN for an perceptual based model (COM-12/10, Nov. 2000; COM-12/D089, Jan. 2003) Open points:  The subjective test procedure is neither defined nor established  Current proposal does not consider real terminals  Extension to the acoustical interface is needed Talking Quality

11. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 11 Current status:  New action points First steps: Music over telephone channels:  Applicability of ITU-R Recommendations?  Modifications on speech quality approaches sufficient? First steps: Noise handling / Noise reduction  Starting point: P.835 describes the subjective test  Impact on clean speech could be handled by P.862 / P.AAM  Improvement / degradation of noisy speech could be handled by framing of listening quality models  Quality of residual noise is an open point, an ‘Annoyance model’ is needed Audio- and noise-signals

12. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 12 Current status:  New action point  Audio-visual quality aspects in telecommunication scenarios (lower bitrate, small image sizes) are interesting for SG12  Initiating contribution (COM-12/D180, Feb. 2001)  Cooperation with SG9 and VQEG  Joint Rapporteur’s Group on Multi-Media Quality Assessment is already established  Drafting of testplans Audio-visual quality assessment

13. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 13 To be discussed in ITU-T:  Is a Recommendation / Appendix for wideband speech assessment at electrical interfaces a migration step to a more complete solution only?  How should the Recommendation(s) for measurements at the acoustical interfaces be structured?  Inclusion of wide-band?  Separation of handsfree (separate model or only ‘switch’)?  Handling of binaural signals compared to classical handset?  Two / four separate models corresponding to the combinations of interfaces ?  electrical – electrical  acoustical – electrical  electrical – acoustical  acoustical – acoustical Structuring of work

14. SwissQual AG – Your QoS Partner Workshop on Wideband Speech Quality in Terminals and Networks: Assessment and Prediction 14 Thank you for your attention!