MOVEMENT COMPENSATION PREDICTION INTER-FRAME CODER

摘要

PURPOSE:To improve the picture quality by quantizing a prediction error in a 2nd quantization step size whose precision is decreased more than that of each block and calculated from a 1st quantization step size as to a block having a precision picture. CONSTITUTION:A 2nd quantization step size calculation section 18 compares a variance signal 17 with predetermined 3 threshold levels th1-th3, classifies each block into 4 quantization classes and calculates a 2nd quantization step size 20 from a 1st quantization step size 19 based on the quantization class. Then a smaller 2nd quantization step size 20 is applied to a block with high precision of an input picture signal 2 more than the 1st quantization step size 19. Thus, the moving picture coding is implemented without losing the precision of an original picture while limiting the generating code quantity.