International standardization recommendation H.261 of a video codec for videophone and video conferencing have specified only the fundamental part, and a pre-processing, a post-processing, coding control can be performed freely. We have developed a human face region adaptive filter, brightness compensation, quantization stepsize control, threshold control, a post filter, etc., and quality of image has been improved 2 or more times compared with before. Moreover, a miniaturization of some circuits has been examined and seven LSIs for the exclusive use have been developed.
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