Audio pitch coding method, apparatus, and program storage device calculating voicing and pitch of subframes of a frame

摘要

A pitch coding method is provided for calculating and coding the pitch of each sub frame of a speech input that is divided into a plurality of frames which are separated into a plurality of sub frames. The method calculates the pitch of each of the sub frames included in one or more of the frames, and determines whether or not the speech input is a voiced sound accompanying the vibration of a vocal chord. If it is determined that a head sub frame of a first speech input is the voiced sound, the pitch of the head sub frame is coded. Otherwise, if a subsequent sub frame is determined to be the voiced sound, a standard pitch value is selected and coded for the head sub frame. The method also determines whether a frame preceding the subsequent sub frame is judged to be the voiced sound, and if so the difference between the pitch of the preceding frame and the pitch of the subsequent frames is calculated and coded. If the preceding frame is not the voiced sound, the difference between the selected standard pitch and the subsequent frame's pitch is calculated and coded.