| 摘要 |
PROBLEM TO BE SOLVED: To perform efficient encoding with a small number of bits by encoding a multichannel audio signal by making use of APCM and the correlation among channels. SOLUTION: An audio signal in a given time area is mixed by a 1st mixer 160. An audio signal changed into a frequency area by a filter 100 is mixed by a 2nd mixer 110 to generate an audio signal of the frequency range corresponding to a stereophonic system. Then a signal which is inputted to a multichannel processor 130 and transmitted is discriminated from a signal which need not be transmitted. Then the masking levels of the respective channels calculated by a mental acoustic part 170, the process result of the multichannel processor 130, and the process result of an APCM preprocess part 120 are used by a bit allocator 140 to allocate bits to respective audio signals. A quantizer 150 performs APCM quantization for the output signal of the filter 100 by using the allocation result and transmits the result. |
