Patent ID: 8352249
Filing Date: 2013-01-08
Classification: G10L

Abstract:
1. A coding apparatus comprising: a monaural signal generation processor that generates a time-domain monaural signal by combining a first channel signal and a second channel signal in an input stereo signal and generates a time-domain side signal, which is a difference between the first channel signal and the second channel signal; a first transformation processor that transforms the time-domain monaural signal to a frequency-domain monaural signal; a second transformation processor that transforms the time-domain side signal to a frequency-domain side signal; a first quantizer that quantizes the frequency-domain monaural signal, to acquire a first quantization value; a second quantizer that quantizes a low frequency part of the frequency-domain side signal, the low frequency part being equal to or lower than a predetermined frequency of the frequency-domain side signal, to acquire a second quantization value; a first scale factor calculator that calculates, in the frequency domain, a first energy ratio between a high frequency part of a frequency-domain first channel signal that is higher than a predetermined frequency of the frequency-domain first channel signal and a high frequency part of a frequency-domain monaural signal that is higher than a predetermined frequency of the frequency-domain monaural signal; a second scale factor calculator that calculates, in the frequency domain, a second energy ratio between a high frequency part of a frequency-domain second channel signal that is higher than a predetermined frequency of the frequency-domain second channel signal and a high frequency part of a frequency-domain monaural signal that is higher than a predetermined frequency of the frequency-domain monaural signal; a third quantizer that quantizes the first energy ratio to acquire a third quantization value; a fourth quantizer that quantizes the second energy ratio to acquire a fourth quantization value; and a transmitter that transmits the first quantization value, the second quantization value, the third quantization value and the fourth quantization value.