| 摘要 |
<p>PROBLEM TO BE SOLVED: To attain good coding with a quantization characteristic having a small dynamic range, without increasing a device scale and without deterioration in overload noise. SOLUTION: In the case that a transformation coefficient obtained by applying orthogonal transformation to a prediction error signal with a same dynamic range as that of an input signal for each block is quantized and coded, an adaptive quantization device 3 obtains a tentative local decoding signal from a quantized prediction error signal that is obtained by applying inverse orthogonal transformation to a tentative quantization output and compares the tentative local decoding signal with the input signal. In the case that the tentative local decoding signal exceeds a dynamic range, control is conducted by using a conversion signal applying orthogonal transformation to the signal exceeding the dynamic range, and the conversion signal is adaptively quantized and is outputted so that the tentative local decoding signal does not exceed the dynamic range of the input signal.</p> |
