| 摘要 |
<p>PURPOSE:To prevent the generation of mismatch errors by setting a present step size so as to be different from a previous step size, using the set present step size and quantizing a present coefficient block. CONSTITUTION:A step size controller 51 calculates the step size for quantizing the present coefficient block, that is a discrete cosine transformation (DCT) coefficient block obtained from the present picture block of present pictures. Further, the step size controller 51 reads stored previous picture quantization scale code (QSC) parity information from a QSC parity memory 53 and judges whether or not a calculated QSC parity is the same as a previous picture QSC parity. When it is different, the step size controller 51 supplies the present QSC and QT to a quantizer 12. The quantizer 12 uses the step size expressed by the present QSC and QT supplied by the step size controller 51 and quantizes the present coefficient block.</p> |
