| 摘要 |
An image data processing apparatus includes a converter for subjecting each block to a discrete cosine transform (DCT) to convert blocks into DCT coefficients, a first memory for temporarily storing the DCT coefficients, a second memory for storing threshold values of a quantization matrix which is used for quantizing the DCT coefficients, a quantizing part for quantizing the DCT coefficients, a differential part for obtaining a difference in D.C. components of quantized DCT coefficients related to present and previous blocks, a zero detector for detecting whether or not A.C. components of the quantized DCT coefficient are zero coefficients, a counter for counting a number of successive zero coefficients of the A.C. components, a coder for subjecting the D.C. and A.C. components to a Huffman coding to output a coded D.C. and A.C. components, a first register for storing an address of an arbitrary DCT coefficient, a comparator for comparing an address where the DCT coefficient is stored in the first memory and the address in the first register, and a second register for holding the DCT coefficient output from the converter when the two compared addresses match.
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