ENCODER, DECODER, AND THE METHODS THEREFOR

摘要

Provided is an encoder which can decode a high-quality stereo signal while keeping the amount of information in the bit allocation information to a minimum when a scalable coding technique is used for a stereo signal. In the encoder, a principal component analysis (PCA) converter (101) PCA converts the left signal and the right signal of the stereo signal and generates the main signal of the first layer and the sub-signal of the first layer. In the first layer to the M-th layer (where M is a natural number, 2 or greater), an adaptive residual encoder (102-m) (where m is a natural number from 1 to M) compares the importance of the main signal of the m-th layer and the importance of the sub-signal of the m-th layer, selects the signal having the higher importance, encodes the selected signal, and generates the encoded data of the m-th layer. From the first layer to the M-1-st layer, the adaptive residual encoder (102-m) generates the signal obtained by subtracting the decoded signal of the encoded data of the m-th layer from the selected signal as the main signal of the m+1-st layer, and generates the unselected signal as the sub-signal of the m+1-st layer.