MOTION COMPENSATED PREDICTIVE INTER-FRAME ENCODER

摘要

PURPOSE: To improve picture quality by calculating a second step size from a first step size and quantizing an input signal and using the second step size. CONSTITUTION: A second quantizing step size 20 and a quantizing class 21 are calculated from the variance signal 17 for an encoding block and a first quantizing step size 19 by a second quantizing step size calculating part 18. The size 19 is dound corresponding to a residual code amount 24 in a code memory part 23 by a first quantizing step size calculating part 22. Then, the calculating part 18 compares the variance signal 17 with three threshold values decided in advance and divides the respective blocks into four quantizing classes. Corresponding to these quantizing classes, the size 20 is calculated from the size 19. Corresponding to the size 20, a quantizing part 15 calculates a predictive error orthogonal transformation coefficient 25 and an inverse orthogonal transforming part 26 inversely orthogonally transforms the coefficient 25. Then, a predictive error signal 27 containing a quantizing error is calculated, and a regenerative image calculating part 28 adds the predictive error signal 27 containing the quantizing error and a predictive signal 10 and calculates an encoded block regenerative image 29.