Transcoded speech contemporary objective quality measurements reliability

Speech transcoding (coder tandeming) is unavoidable source of transmission quality degradation for ad-hoc or permanently interoperating networks. Test methodology and results of voice transmission quality measurement for transcoded voice in coder tandem arrangement is described. The objective tests have been performed using ITU-T P.862 (PESQ) and P.563 (3SQM) algorithms. The subjective tests results based on ITU-T P.800 are also presented. The objective results confirm additional degradations caused by abovementioned transcodings, highlighting coder combinations causing extreme impairments. The subjective tests quantify objective measurement accuracy.