Objective speech quality evaluation of mediumband and narrowband real-time speech coders

We consider in this paper the problem of developing and testing a procedure for objective evaluation of the speech quality of real-time speech coders. We validate this evaluation procedure by computing the objective quality scores over a test bed of five mediumband and narrowband real-time speech coders and correlating the scores with subjective judgments generated by the Diagnostic Acceptability Measure test. We report on the performance of several published objective measures. Also, we describe and suggest solution approaches to two related problems: synchronize in time a real-time coder´s output with its input, and design a database of input-speech sentences to be used in objective speech quality evaluation. We present various experimental results of this ongoing work.