| 摘要 |
<p>PURPOSE:To attain coding with less generation of distortion by coding an HH signal so as to calculate a code length, deciding the code length assigned to an LL signal based on the result and applying coding to the LL signal so as not to exceed the assigned code length. CONSTITUTION:After an HH signal is quantized by a quantizer 107, the result is coded by a variable length coder 211, the code length is calculated by a code length calculation device 214 and a code length assignment device 215 decides the code length assigned to the LL signal based on the result of calculation. Since the sum of the code lengths of the LL, HH signals is set to a prescribed value in advance, the code length assigned to the LL signal is fluctuated proportional to the fluctuation of the code length of the HH signal. As to the LL signal whose code length is assigned, a DCT arithmetic unit 205 applies two-dimension DCT and selects the quantization method in the quantizer 206 so as not to exceed the assigned code length and a variable length coder 210 applies coding. The quantization method in the quantizers 208, 209 is selected to the LH, HL signals so that the predetermined code lengths are not exceeded and the variable length coders 212, 213 apply the coding.</p> |
