| CPC G10L 19/008 (2013.01) [G10L 19/032 (2013.01); G10L 25/21 (2013.01); G10L 25/69 (2013.01)] | 16 Claims |
|
1. A sound signal high-frequency compensation method for obtaining, for each frame, an n-th channel compensated decoded sound signal ˜X′n that is a signal obtained by compensating a high frequency of an n-th channel purified decoded sound signal ˜Xn obtained by performing signal processing in a time domain on an n-th channel decoded sound signal Xn (n is each integer of 1 or more and N or less) that is a decoded sound signal of each channel of stereo obtained by decoding a stereo code CS, the sound signal high-frequency compensation method comprising:
an n-th channel high-frequency compensation gain estimation step of obtaining, for the each frame with respect to the each channel, an n-th channel high-frequency compensation gain ρn that is a value for bringing high-frequency energy of the n-th channel compensated decoded sound signal ˜X′n close to high-frequency energy of the n-th channel decoded sound signal Xn; and
an n-th channel high-frequency compensation step of obtaining and outputting, for the each frame with respect to the each channel, a signal obtained by adding the n-th channel purified decoded sound signal ˜Xn and a signal obtained by multiplying a high-frequency component of the n-th channel decoded sound signal Xn by the n-th channel high-frequency compensation gain ρn, as the n-th channel compensated decoded sound signal ˜X′n, wherein
a signal obtained by passing the n-th channel decoded sound signal Xn through a high-pass filter is used as an n-th channel compensation signal X′n,
the n-th channel high-frequency compensation step
obtains, for each corresponding sample t, a sequence based on a value ˜x′n(t)=˜xn(t)+ρn× x′n(t) obtained by adding a sample value ˜xn(t) of the n-th channel purified decoded sound signal ˜X′n and a value ρn×x′n(t) obtained by multiplying the n-th channel high-frequency compensation gain ρn by a sample value x′n(t) of the n-th channel compensation signal X′n, as the n-th channel compensated decoded sound signal ˜X′n, and
the n-th channel high-frequency compensation gain estimation step
obtains, for each corresponding sample t, a sequence based on a value ˜x″n(t)=˜x′n(t)+ x′n(t) obtained by adding the sample value ˜xn(t) of the n-th channel purified decoded sound signal ˜Xn and the sample value ˜x′n(t) of the n-th channel compensation signal ˜X′n, as an n-th channel temporary addition signal ˜X″n, and
obtains the n-th channel high-frequency compensation gain ρn that is a value larger as high-frequency energy ˜EXn of the n-th channel purified decoded sound signal ˜Xn is smaller than high-frequency energy ˜EXn of the n-th channel decoded sound signal Xn, and is a value larger as a difference between the high-frequency energy of the n-th channel purified decoded sound signal ˜Xn and high-frequency energy of the n-th channel temporary addition signal ˜X″n is smaller than the high-frequency energy EXn of the n-th channel decoded sound signal Xn.
|