| 摘要 |
Disclosed are a quantizer, encoder, and the methods thereof, wherein the computational load is reduced when the values related to the transform coefficients of the principal component analysis transform are quantized when a principal component analysis transform is applied to code stereo. A quantizer (110) is comprised of a power correlation calculation unit (111) which calculates the power (C11) of the left channel signal, the power (C22) of the right channel signal, and the correlation (C12) between the left channel signal and the right channel signal; an intermediate value calculation unit (112) which calculates the intermediate value (C1122) which is the difference between the power (C11) and the power (C22); a codebook (113) which holds a plurality of sets of the coefficients ?1,n,?2,n related to the transform coefficients of the principal component analysis transform and the code; and a quantizer (114) which calculates the sum of the first multiplication result obtained by multiplying the coefficient ?1,n by the correlation value C12 and the second multiplication result obtained by multiplying the coefficient ?1,n by the intermediate value C1122 as the cost function E, selects the coefficients ?1,n,?2,n where the cost function E becomes the maximum, and fetches the code related to the selected coefficients ?1,n,?2,n as the quantized code. |
