Encoding apparatus, encoding method, and computer product

摘要

An encoding apparatus (400) uses M/S encoding to compress a stereo signal using a sum signal (M(f)) and a difference signal (S(f)) of a left component signal (L(f) and a right component signal (R(f)) of the stereo signal. The encoding apparatus (400) includes a calculating unit (406) that calculates, for each of a plurality of frequency bands in the stereo signal, the complexity of the sum signal (M(f)) and complexity of the difference signal (S(f)); a setting unit (407) that sets, based on the complexity, an allocation rate of bits to be allocated in quantizing the sum signal (M(f)) and the difference signal (S(f)); and a quantizing unit (408, 409) that quantizes the sum signal (M(f)) and the difference signal (S(f)) based on the allocation rate. In this way, bits can be re-allocated from a frequency band having relatively low complexity in the difference signal or in the sum signal, to one or more frequency bands of relatively high complexity in the sum signal or in the difference signal respectively.