A system, method and computer readable medium for quantizing class information and pitch information of audio is disclosed. The method on an information processing system includes receiving audio and capturing a frame of the audio. The method further includes determining a pitch of the frame and calculating a codeword representing the pitch of the frame, wherein a first codeword value indicates an indefinite pitch. The method further includes determining a class of the frame, wherein the class is any one of at least two classes indicating an indefinite pitch and at least one class indicating a definite pitch. The method further includes calculating a codeword representing the class of the frame, wherein the codeword length is the maximum of the minimum number of bits required to represent the at least two classes and the minimum number of bits required to represent the at least one class.