802 16 IP Telephony Lab Perceptual Evaluation of

802. 16 IP Telephony Lab Perceptual Evaluation of Speech Quality (PESQ) Speaker: Wen-Jen Lin Date: Dec. 3 2009 1 TAC 2000/2000. 7

802. 16 IP Telephony Lab Outline <Introduction <ITU-T P. 862 <P. 862. 3 <P. 862. 2 <P. 862. 1 <P. 862 - Overview of the basic philosophy used in PESQ <Conclusion <Experience <Demo PESQ program <Reference 2 TAC 2000/2000. 7

802. 16 IP Telephony Lab Introduction <Classic Quality Measurement l Noise Ratio l Frequency Response Functions etc. l Speech coding ( ETSI GSM EFR/AMR, ITU-T G. 728/729/723. 1 etc) <New types of distortions l Voice over IP (packet loss and variable delay) l Voice over ATM (cell loss) l Voice over mobile (GSM, UMTS, frame repeat, front end clipping, comfort noise generation) 3 TAC 2000/2000. 7

802. 16 IP Telephony Lab Introduction (cont. ) <PSQM (Perceptual Speech Qualify Measure) l P. 861 - The first international standard for the perceptual quality measurement of telephoneband (300 -3400 Hz) speech signals. l The scope of recommendation P. 861 was limited to the assessment of telephone-band speech codecs only. 4 TAC 2000/2000. 7

802. 16 IP Telephony Lab ITU-T P. 862 <P. 862 l Perceptual evaluation of speech quality (PESQ): An objective method for end-to-end speech quality assessment of narrow-band telephone networks and speech codecs l Amendment 2 <P. 862. 1 l Mapping function for transforming P. 862 raw result scores to MOS -LQO <P. 862. 2 l Wideband extension to Recommendation P. 862 for the assessment of wideband telephone networks and speech codecs <P. 862. 3 l Application guide for objective quality measurement based on Recommendations P. 862, P. 862. 1 and P. 862. 2 5 TAC 2000/2000. 7

802. 16 IP Telephony Lab Application <P. 862. 3 – Example of measurement set-up and terminology 6 TAC 2000/2000. 7

802. 16 IP Telephony Lab P. 862. 1 <MOS-LQO (P. 800. 1) <ITU-T Rec. P. 862 provides raw scores in the range – 0. 5 to 4. 5. <The mapping function: 7 TAC 2000/2000. 7

802. 16 IP Telephony Lab Figure of Mapping Function 8 TAC 2000/2000. 7

802. 16 IP Telephony Lab P. 862 - Overview of the basic philosophy used in PESQ 9 TAC 2000/2000. 7

802. 16 IP Telephony Lab P. 862 - Overview of the basic philosophy used in PESQ (cont. ) 10 TAC 2000/2000. 7

802. 16 IP Telephony Lab Addition of background noise 11 TAC 2000/2000. 7

802. 16 IP Telephony Lab Factors for which PESQ had demonstrated acceptable accuracy <Speech input levels to a codec <Errors in the transmission channel between an encoder and a decoder <Bit rates if a codec has more than one bit-rate mode <Transcodings <Environmental noise in the sending side 12 TAC 2000/2000. 7

802. 16 IP Telephony Lab PESQ is not intended to be used to assess <Effect of listening level <Conversational delay <Talker echo, where a subjects hears his own voice delayed <Talker sidetone, where a subjects may hear its own voice distorted <Non-intrusive measurements, where only output signals are available from the system music 13 TAC 2000/2000. 7

802. 16 IP Telephony Lab which PESQ has not currently been validated 14 TAC 2000/2000. 7

802. 16 IP Telephony Lab Conclusion <PESQ has been evaluated on a very wide range of speech codecs and telephone network tests. <It has been found to produce accurate predictions of quality in the presence of diverse end-to-end network behaviors. <PESQ represents a significant step forward in the accuracy and range of applicability of objective speech quality assessment methods. 15 TAC 2000/2000. 7

802. 16 IP Telephony Lab Head and Torso Simulator(HATS) 16 TAC 2000/2000. 7

802. 16 IP Telephony Lab Spirent Abacus 17 TAC 2000/2000. 7

802. 16 IP Telephony Lab Abacus Control GUI 18 TAC 2000/2000. 7

802. 16 IP Telephony Lab Testbed DSLAII Handset Interface Controller Malden 19 TAC 2000/2000. 7

802. 16 IP Telephony Lab RTP Flow 20 TAC 2000/2000. 7

802. 16 IP Telephony Lab Demo PESQ program 21 TAC 2000/2000. 7

802. 16 IP Telephony Lab Reference < HATS - http: //www. bksv. com/doc/bp 2240. pdf < ITU-T Rec. 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”, International Telecommunication Union, Geneva, Switzerland (2001 Feb. ) < Malden - http: //www. malden. co. uk/dsla. htm < Perceptual Evaluation of Speech Quality (PESQ), the new ITU standard for end-to-end speech quality assessment. Part II – Psychoacoustic model - http: //www. mp 3 tech. org/programmer/docs/2001 -P 03 b. pdf < Spirent - http: //www. spirent. com/ 22 TAC 2000/2000. 7