To accurately estimate comprehensive quality in two-way communication service using a voice and a video medium.
As factors responsible for a deterioration in quality in the two-way communication service between terminals, the following are monitored: a video bit rate Br; a frame rate Fr; a video invalid packet rate Pv; a voice invalid packet rate Pa; and a delay time D. On the basis of the factors responsible for the deterioration in quality, estimation is made to a factor score S1 for an aesthetic feeling and a factor score S2 for an uplifting feeling as mental factors with respect to quality received by a user. An evaluation value MOS for the general quality is obtained by substituting the estimated factor score S1 for the aesthetic feeling and factor score S2 for the uplifting feeling for an expression using A, B, C as constants: MOS=A×S1+B×S2+C.
HAYASHI TAKANORI
Hiroro Kurokawa
Shigeki Yamakawa