| 摘要 |
A coding system in accordance with the present invention includes a control signal generating circuit for generating a control signal indicative of a quantity of band limitation by calculating a ratio of an area of motion from an input video signal. A band limiter band-limits a transform-coded video signal in response to the control signal. For example, when the picture is stationary or little moved, the transform-coded video signal is not band-limited at all; when the area of motion is medium, high frequency components of a part of the video signal are omitted to cope with an increase in the amount of data generated; and when the area of motion is extremely great, many high frequency components are omitted to accommodate a rash of data. A prediction coding circuit predictively codes the band-limited video signal before the latter is sent out to a transmission path.
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