Validation of ITU-T P.863 for low bit-rate coded speech quality measurements

The paper presents new results of speech transmission quality measurements obtained by a recently developed algorithm POLQA - ITU-T P.863. Even though the algorithm is declared by its authors as not intended for coding technologies under 4kbit/s, our research shows acceptable accuracy for databases containing significant portion of low bit-rate coded samples, namely by MELPe 2.4 kbit/s. The POLQA results are compared with subjective test results based on ITU-T P.800. The subjective tests quantify objective measurement accuracy.