| 摘要 |
PROBLEM TO BE SOLVED: To effectively prevent generation of pre-echoes and post-echoes and to enable effective coding that employs an auditory psychology model. SOLUTION: Gain control circuits 103a to 103d detect the attacking and releasing parts of waveform signals and perform gain control on the waveform signals before the attacking parts and at the releasing parts by using gain controlled variables that are obtained adaptively according to the characteristics of the waveform signals. From a window circuit 108 for an auditory model to an auditory model employing circuit 110, a masking level based on an auditory psychology model is calculated from frequency components converted from the waveform signals, and a quantization accuracy determining circuit 111 determines the accuracy of quantization using the masking level. Window circuits 102a to 102d and converter circuits 104a to 104d convert the waveform signals into a plurality of frequency components, and quantization circuits 106a to 106d quantize the plurality of frequency components using the quantization accuracy. |
