| 摘要 |
PURPOSE:To attain detailed control of quantity of generated information with a requantization step width by coding a coefficient data in a same sub block with a bit number in response to a level of a maximum value among coefficient data requantized in each sub block. CONSTITUTION:Conversion coding is applied to a block comprising (nXn) picture elements and a DC component is sent in a prescribed bit number among coefficient information obtained, and (n<2>-1) sets of AC components are divided into m-set of sub blocks and the coefficient data in each sub block is requantized (5) and sent. Then a maximum value in the requantized coefficient data is detected (11, 14), the coefficient data in one and same sub block is coded in a bit number in response to the level of the maximum value. Thus, the quantity of generated information corresponding to the requantization step width is calculated and then the requantization step width is set optimum to control the quantity of the generated information desirably. |
