| 摘要 |
Image data is encoded into sync blocks of fixed length and maximum data volume by dividing a vertical interval of image data samples, such as a field or frame of samples, into a plurality of blocks and deriving the orthogonal transform of the image data samples in each block. A block of conversion coefficients that are produced by the orthogonal transform are quantized with the same quantizing step to produce weighted, quantized conversion coefficients having a weighting factor that is a function of the visual activity of that block. Then, the weighted, quantized conversion coefficients of a block are variable length coded and the variable length codes of a predetermined number of blocks are combined into a sync block of fixed length.
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