METHOD AND APPARATUS FOR SELECTING A SPEECH ENCODING RATE IN A VARIABLE RATE VOCODER

摘要

PPROBLEM TO BE SOLVED: To provide a method for detecting whether an input sound is in a non-sound state, when an encoding rate of a variable rate vocoder is determined. PSOLUTION: In order to detect whether a frame of the input signal has an audio signal or silence (non-sound), an index of a signal to noise ratio (SNR) of the input signal is determined. A first scaling factor and a second scaling factor are selected or calculated by using the index of the SNR, and a threshold in a low frequency band and the threshold in a high frequency band are calculated by using the first and second scaling factors. PCOPYRIGHT: (C)2008,JPO&INPIT