QUANTIZATION MATRIX FOR STILL AND MOVING PICTURE CODING

摘要

An encoder and a decoder for still and moving picture are disclosed. The encoder has a memory for storing a default quantization matrix including a plurality of quantization elements having predetermined values. Also, a generator is provided for producing a particular quantization matrix after a number of frames. The particular quantization matrix is read in a predetermined zigzag pattern, and the reading is terminated at a selected position which is in the middle of the zigzag pattern. An end code is added after the read quantization elements of a former portion of the particular quantization matrix. The quantization elements in the default quantization matrix are read in the same zigzag pattern from a position immediately after the selected position, and producing a latter portion of the default quantization matrix. The former portion of the particular quantization matrix and the latter portion of the default quantization matrix are synthesized to form a synthesized quantization matrix.