| 摘要 |
<p>Derived from a picture input signal and a motion vector signal in a block matching type motion compensation encoding device, a prediction error signal is quantized by a controllable quantizer into a quantized signal for encoding together with the motion vector signal. Supplied with frame pulses, a controller produces a control signal with a predetermined value for making the quantizer quantize a zero signal instead of the error signal and with a different value for operating the quantizer merely as a forward quantizer. An amount of encoded information is reduced when the predetermined value appears once in two or three frame periods. For smoother movement of a movable part in reproduced pictures, the zero signal is not substituted in each duration in which motion vectors are either greater in magnitude, not identical with a representative vector, or less correlated with corresponding motion vectors in a previous picture for which the zero signal is not substituted. Each duration may be an interval of time during which the error signal has a greater absolute value. The controllable quantizer may be a combination of the forward quantizer and a selector controlled by the control signal to select the zero signal and either the error signal or an output signal of the forward quantizer.</p> |
