Assessment of CELP codecs quality in multi-lingual environment

Abstract

This paper investigates the performance of CELP speech codecs over different languages. The English language has had a dominating influence in the advance of telecommunications. With many of the major developments coming from primarily English speaking areas there is the risk that these advances may not be linguistically robust. It is noted that quality of a speech produced by voice codecs mainly is assessed using samples of English language. Some investigation show that language influence to codecs performance could be noticed. In order to judge the performance of the most popular CELP voice codecs (Speex and AMR), we encoded and decoded the speech samples from three different languages: English, Arabic and Lithuanian. The quality of transformed speech signals was estimated using two quality estimation algorithms 3SQM (ITU recommendations P.563) and PESQ (ITU recommendations P.862). The experiments results showed quality bias toward the English language—the scores were higher and the performance was more stable.