| 摘要 |
PURPOSE:To decrease the distortion of a part with a high brightness by increasing bit number assigned to the part with a high brightness in comparison with a bit number assigned to the part with a low brightness in the case of compressing a digital video signal. CONSTITUTION:A maximum value MAX for each block is detected from a picture element data PD of a digital video signal SDV supplied to a maximum value detection circuit 3. A minimum value MIN is detected from a picture element data PD of the digital video signal SDV supplied to a minimum value detection circuit 4 for each block. The minimum value MIN is subtracted from the maximum value MAX at a subtractor circuit 7 to form a dynamic range DR. The bit number assigned to a block is increased as the maximum value MAX in the block in a bit assignment table TB is increased and quantization is applied in an interval of a finner quantization step. On the other hand, as the maximum value MAX in the block is smaller, the assigned bit number to the block is reduced and quantization is applied in a coarse quantization step interval. |
