1 / 19

v1.0 - 20050426

Telecommunications Industry Association TR41.3.12-07-05-005-L. v1.0 - 20050426. PESQ and Recording Devices Kevin J Cross Malden Electronics Ltd. PESQ – ITU-T Rec. P.862. Speech Quality Metric Compares a clean reference speech file with a degraded speech file

joshwa
Download Presentation

v1.0 - 20050426

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Telecommunications Industry Association TR41.3.12-07-05-005-L v1.0 - 20050426

  2. PESQ and Recording DevicesKevin J CrossMalden Electronics Ltd

  3. PESQ – ITU-T Rec. P.862 • Speech Quality Metric • Compares a clean reference speech file with a degraded speech file • Predicts a Mean Opinion Score for Listening Quality

  4. Associated Standards • P.862.1 PESQ-LQO • P.862.2 PESQ-WB • P.862.3 Use of PESQ

  5. How PESQ Works Summary of PESQ Process

  6. Benefits of PESQ • A Standard • Calibrated against 250000 test votes • Five years use around the world • Works across a wide range of codecs and networks

  7. Limitations of PESQ • Noise floor and file length • Signal timing • Voiced signal compression – low bit rate codecs

  8. Assessment of Recording Devices • Functionality – Answer, Replay Start & Stop, Interactive DTMF or Voice Activation • Performance under Load • Speech Quality of Recorded Messages

  9. Speech Quality Modifiers • Recording media FA1000f.rst • Codec • Line interface • Network • Line interface • Phone Amplifier and Equaliser • Speaker’s transducer • Speaker’s environment

  10. Test Interfaces • POTS • Handset port • Digital source – TDM or VoIP

  11. Test Stimuli • Language • Phonemic Content • Duration • Quality vvn from 7905 China2f12dbpoor.rst • Gender • Spectral Content • Narrowband and Wideband material • Intermediate Reference System Send Characteristic

  12. Acoustic Connection - Playback • Narrowband speech played back to loudspeaker • Narrowband measurement • Wideband speech played back to loudspeaker • Wideband measurement

  13. Acoustic Connection - Record • Wideband, flat, speech to Artificial Mouth • Use narrowband IRS or mIRS reference for PESQ on playback through narrowband network • Use wideband, flat, reference for PESQ on playback through wideband network

  14. Test Sequence • Laboratory • Measure speech levels • Measure speech quality vs speech levels • Measure speech quality vs background noise type and level • Measure speech quality vs jitter and packet loss • vvn from 7905 China2f12db 0ms 0pct.rst • vvn from 7905 China2f12db 30ms 0pct.rst • vvn from 7905 China2f12db 30ms 1pct.rst

  15. Test Sequence • Field • Measure speech levels • Measure speech quality – two male and two female • Assess jitter and packet loss

  16. Results • Speech quality • Speech levels • Noise • Jitter • Packet loss • Time offsets after jitter buffer

  17. Result Accuracy • Test Equipment vvn from 7905 Thai.rstvvn from 7905 China2.rst • Test Network Eric750if.rst • Speech Levels vvn from 7905 China2.rstvvn from 7905 China2f12db.rst • Codecs vvn from vn f alaw.rstvvn from vn f ulaw.rst • Volume Controls • Automatic Gain Controls

  18. Summary • Optimise Test Equipment and Test Network • Optimise Speech Levels • Choose most favourable Codecs • Keep Volume Controls under lock and key

  19. The Perfect Score

More Related