摘要 |
A lossless encoding processing unit lossless-encodes respective tiles, and stores the encoded data in a memory. A determination unit determines, according to attribute information of each tile, whether the tile of interest is to be lossless- or lossy-encoded, and appends the determination result at the head of lossless-encoded data as a flag. The determination unit counts, in variable CH, the number of tiles determined to be lossy-encoded, during the lossless encoding processing. Every time the CH exceeds one of a plurality of different thresholds, a lossy encoding processing unit decodes lossless-encoded data appended with a lossy flag, applies processing for decreasing the resolution to the decoded data, lossless-encodes the data that has undergone the processing again, and stores the lossless-encoded data in the memory. Upon completion of the lossless encoding processing for one page, the lossy encoding processing unit lossy-encodes the lossless-encoded data appended with the lossy flag.
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