| 摘要 |
PURPOSE:To transmit a natural picture having no uneasy feeling by determining the compressibility based on the density of a picture in a picture element block concerned and the compressibility of the picture element block in the vicinity of said picture element block. CONSTITUTION:For instance, when the picture element block transmitted in a C mode is set to 2/3 of the whole and the picture element block transmitted in an E mode is set to 1/3 of the whole, the number of data (compressibility) transmitted as a whole is 1/2. According to the distribution in the block distortion of all the picture elements, a distortion threshold for deciding whether a virtual C mode or a virtual E mode is distributed or not based on the distortion in the block to some degree. Then, the distortion in the block stored in the timing when a video signal of the next field is inputted is successively read and compared with the distortion threshold to decide the virtual transmission mode. When the read distortion in the block coincides with the distortion threshold, the transmission mode is decided so as to make the ratio of the picture element block considered to be the virtual C mode to a prescribed rate coincide with the ratio of the picture element block considered to be the virtual E mode.
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