METHOD AND DEVICE FOR ENCODING AUDIO SIGNAL, ENCODING AND DECODING SYSTEM, PROGRAM FOR EXECUTING ENCODING, AND RECORDING MEDIUM WITH THE PROGRAM RECORDED THEREON

摘要

PROBLEM TO BE SOLVED: To minimize artifacts caused at the time of switching of a state mode of MS stereo encoding. SOLUTION: A joint stereo encoder 14-1 encodes a digitized audio signal which includes a pair of stereo channels of a left channel and a right channel and has each frame divided into consecutive frames consisting of a plurality of time samples, to one of a plurality of state modes of MS stereo encoding. In this encoding, the joint stereo encoder 14-1 calculates respective energies of the left channel and the right channel of a current frame of the audio signal and determines a state mode of MS stereo encoding of the current frame on the basis of the value of a ratio of the energy of the right channel to that of the left channel and the state mode of MS stereo encoding of at least one just preceding frame. COPYRIGHT: (C)2004,JPO