QUANTIZATION CHARACTERISTIC CONTROL METHOD FOR PICTURE SIGNAL AND PICTURE SIGNAL COMPRESSION-ENCODING DEVICE

摘要

PURPOSE:To perform reproduction without damaging the decoded pictures even when signals for indicating the quantization bit number of picture signals are erroneous. CONSTITUTION:The picture signals 21 are orthogonally transformed in a blocking and orthogonal transformation part 1 and the quantization bit numbers are set for respective blocks in a bit allocation map setting part 2. A basic bit allocation map generation part 4 outputs a basic bit allocation map 24 and a basic quantization characteristic 25 is selected in a basic quantization characteristic selection part 5. A bit difference between a quantization bit allocation map 23 and the basic bit allocation map 24 is calculated in a bit difference calculation part 3 and the basic quantization characteristic is corrected in a quantization step width changing part 6. A quantization processing is performed in a quantization part 7 and a level in the basic quantization characteristic and the level of a corrected part are respectively separated into a basic code 28 and an additional code 29 and outputted.