PICTURE DATA ENCODING AND DECODING DEVICE

摘要

PURPOSE: To provide a picture data encoding and decoding device for eliminating the mismatch of the DCT of an encoder and the IDCT of a decoder and suppressing arithmetic errors. CONSTITUTION: In this picture data encoding and decoding device provided with the DCT processing means 2 of picture data divided into blocks, the quantization means 3 of a DCT coefficient inside the block and an encoding means 4 for variable length encoding quantized data on an encoding side and a means for decoding variable length data to the quantized data, an inverse quantization means for transforming the quantized data to the DCT coefficient and an inverse DCT processing means for restoring the coefficient to the picture data of the block by the IDCT on a decoding side, a DCT control means 5 for storing the value of a fixed point arithmetic table 6 used for a DCT processing in the user area of signals to be transmitted to the decoding side is provided on the encoding side and an inverse DCT control means for taking out the value of the fixed point arithmetic table from the user area and letting the value be used in an inverse DCT processing is provided on the decoding side. Since the DCT processing and the IDCT processing are calculated with the same accuracy, the arithmetic errors are reduced.