| 摘要 |
PROBLEM TO BE SOLVED: To reduce folding distortion, even at a low rate and to reduce visual interference by stepwise switching the resolution of signals, matching quantization distortion and a code amount computed for a quantizer selected stepwise for each channel with a target value and selecting the quantizer for maximizing the resolution of the signals. SOLUTION: In this bit allocation method in multi-channel encoding, input image signals are divided into plural channels of different frequencies. First the resolution of the signals is switched stepwise, and the quantizer is selected stepwise for each channel. Then, the quantization distortion and the code amount are computed or estimated for the selected quantizer, and the quantization distortion and the code amount are compared with prescribed target distortion and target code amount. Further, after satisfying the conditions of turning both of the quantization distortion and the code amount to the target value, the quantizer in the respective channels is selected, so as to maximize the resolution of the signals the signals of the respective channels are quantized, and the quantization index is transmitted. |
