Patent ID: 7986634

Claim:
An apparatus for measuring quality of sound encoded with a variable band multi-codec, comprising: a recording file receiving/generating unit receiving a first recording file in which a natural sound is recorded, and a second recording file obtained by converting the natural sound into digital data using the variable band multi-codec, receiving information obtained by encoding the natural sound using the variable band multi-codec, in the format of a Real Time Protocol (RTP) packet, unpacking the RTP packet, decoding the RTP packet using the variable band multi-codec, and generating a third recording file; a Mean Opinion Score (MOS) value calculating unit repeatedly selecting a file from among the first recording file, the second recording file, and the third recording file, or selecting two files from among the first recording file, the second recording file, and the third recording file, and calculating a MOS value by obtaining a difference between the selected results wherein the MOS value calculating unit calculates a first MOS value on the basis of the first recording file and the second recording file, calculates a second MOS value on the basis of the first recording file and the third recording file, calculates a third MOS value on the basis of the second recording file and the third recording file, and calculates a fourth MOS value on the basis of only the first recording file; and a MOS value comparison unit comparing a plurality of MOS values generated by the MOS value calculating unit, with each other, and detecting a cause of sound quality deterioration wherein the MOS value comparing unit determines that the cause of sound quality distortion is the variable band multi-codec if the first MOS value is smaller than the fourth MOS value, and determines that the cause of the sound quality distortion is the network or a system's status if the second MOS value is smaller than the third MOS value.