| 摘要 |
<p>PURPOSE:To generate a code quantity in matching with a line rate by predicting a relation between a generated code quantity of a block to be coded next and a quantization step width so as to select a quantization width generating a code quantity in matching with the line rate. CONSTITUTION:A quantization control circuit 110 introduces a relation equation between a generated code quantity and a quantity step width around a block to be coded depending on the generated code quantity and the quantity step width outputted from a coding circuit 105, decides the quantity step width from the generated code quantity in matching with the line rate and outputs it to a quantization circuit 104. A conversion coefficient quantized by the quantization circuit 104 is also inputted to an inverse quantization circuit 112, in which the quantized conversion coefficient is restored into the conversion coefficient, it is inputted to an inverse orthogonal transformation circuit 108, where the coefficient is restored into a prediction error. The prediction error outputted from the inverse orthogonal transformation circuit 108 is added to a predicted value from a frame memory 113 at an adder 109 to obtain a reproduction picture element. Thus, the quantity step width is controlled with high accuracy.</p> |
