MOVING COMPENSATION PREDICTION INTER-FRAME CODER

摘要

PURPOSE:To limit produce code quantity and to improve the picture quality by measuring a characteristic relating to the accuracy of an input television signal of a block subjected to in-frame coding and decreasing the size in consecutive block groups quantized in a same quantization step size. CONSTITUTION:A mean value variance calculation means 25 calculates a mean value mu and a variance sigma<2> of picture elements for each block of an input television signal 2. Then the accuracy for each block of the input television signal 2 is decided by the variance sigma<2> of the picture elements in the block. Then the orthogonal conversion coefficient is quantized in a 2nd quantization step size decreasing the step size 24 proportional to the accuracy of the block as to blocks whose mean value of picture elements is a prescribed value or over in consecutive blocks to be quantized in a 1st quantization step size 24 being a reference. Thus, while the generated code quantity is limited, the picture quality of the block having accurate picture is improved.