A Comparative Study of VoIP Quality Measurement from G.711 and G.729 Using PESQ and Thai Speech

Abstract

This paper presents the study of VoIP quality measurements from two popular codecs, G.711 and G.729, using the methods of Perceptual Evaluation of Speech Quality (PESQ) and Thai speech. In this study, from four lists of Thai speech, it has been found that G.711 provides better voice quality than G.729 in every condition of packet loss. Also, it has been found that Objective Listening Quality - Mean Opinion Score (MOS-LQO) of male speech is slightly higher than MOS-LQO of female speech, whereas MOS of child speech is the lowest. Then, MOS-LQO values from four Thai speech lists have been compared. Next, MOS-LQO from PESQ of male and female speech at the best condition have been compared with the Subjective Listening Quality Mean Opinion Score (MOS-LQS) from ACR listening tests in another laboratory. Lastly, referring to packet loss effects, objective MOS from PESQ have been compared with subjective MOS from conversation tests. It has been found that there is no significant difference among MOS-LQO from the four Thai speech lists, but it has been found that there is a significant difference between subjective MOS and objective MOS from each codec in each condition. Therefore, one can say that this is evidence that PESQ requires intensive study with Thai speech to modify PESQ for VoIP quality measurement in Thai environments confidently.