| 摘要 |
PURPOSE:To prevent deterioration in picture quality at the time of dubbing by reducing fluctuation of quantization distortion due to an infinitesimal fluctuation of a dynamic range between upper and lower threshold levels. CONSTITUTION:A dynamic range detection circuit 3 obtains a dynamic range DR specified by a maximum value MAX and a minimum value MIN of plural picture element data included in a block and picture element data in a block are coded in an allocation bit number suitable for the dynamic range DR obtained in the unit of blocks in the high efficiency coder, and an area of a certain range is provided to an upper and a lower threshold level of the dynamic range DR representing a boundary where the allocation bit number is changed and a bit length decision circuit 6 is provided to allocate a different bit number from an allocation bit number decided corresponding to the upper and lower threshold level in an area of a certain range. |
