|Coding method for using multi channel audio signals
|Sept. 28, 1999/ Oct. 2, 1996
|Ueno; Masatoshi, Miyamori; Shinji
|ATRAC2/3 Gain Control.
|There is provided a coding method which can effectively prevent a pre-echo and a post-echo from being generated and can perform effective coding to which an psycho-acoustic model is applied. A coding apparatus according to the coding method of the present invention detects the attack and release portions of a waveform signal, and performs gain control to a waveform signal before the attack portion and the waveform signal of the release portion by using a gain control amount adaptively calculated according to the characteristics of the waveform signal. An psycho acoustic model window circuit to an aural model application circuit calculate a masking level based on the psycho-acoustic model from a frequency component obtained by transforming the waveform signal, and a quantization precision determination circuit determines a quantization precision by using the masking level. An window circuit and a transform circuit transform the waveform signal into a plurality of frequency components. The quantization circuit quantizes the plurality of frequency components by using the quantization precision.