| 摘要 |
The invention provides a reversible coding system for an interlaced scanned moving picture based on reversible discrete cosine transform which controls selection of frame/field discrete cosine transform so as to assure a high degree of compatibility with an ordinary discrete cosine transform coding system. A motion compensated predictive error is detected from an input signal, and a frame-scan block and a field-scan block are produced for each block of the input signal by a frame/field scan production circuit. One of the blocks is selected by a switch, and reversible discrete cosine transform is performed for the selected block. Upon the selection, first and second estimated error calculation circuits estimate error amounts when reversible discrete cosine transform is performed for the frame- and field-scan blocks and then inverse discrete cosine transform is performed for the resultant blocks. The error amounts are compared with each other, and the lower one of them is selected by a comparator.
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