DATA PROCESSOR, DATA PROCESSING METHOD AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To efficiently decode JPEG-coded data. SOLUTION: JPEG-coded data are made into DCT coefficients (quantized DCT coefficients) quantized by entropy-decoding, and a quantization table used for JPEG coding is separated from the coded data. A forecasting tap extracting circuit 41 and a class tap extracting circuit 42 extract a necessary coefficient from the quantized DCT coefficients, and compose the forecasting tap and the class tap, respectively. A class classification circuit 43 performs class classification based on the class tap and the quantization table, and a coefficient table storage part 44 supplies a tap coefficient corresponding to the class obtained as a result of the class classification to a product-sum operation circuit 45. The product-sum operation circuit 45 performs a linear predictive operation by using the tap coefficient and the class tap, and obtains the decoded image data.