A television signal which has a motion vector code signal and a prediction error code signal, is separated by a demultiplexer into a prediction error code signal and a motion vector code signal. These signals are decoded. A variable delay circuit receives an immediately preceding television signal from a frame memory and produces a prediction signal in response to the decoded motion vector signal. An adder receives the decoded prediction error signal and the prediction signal and produces a decoded television signal. A noise reducer reduces a small interframe variation component of the decoded television signal. This signal is converted by a D/A converter to an analog signal.
Video signal information derived from a high definition source is conveyed via two channels. A first channel conveys relatively low spatial resolution, high temporal resolution video information compatible with a standard television receiver. An auxiliary second channel conveys relatively high spatial resolution, low temporal resolution video information. A high definition television receiver reconstructs original high definition information from the first and second channel information.
A video signal compressor includes apparatus for generating motion vectors for respective blocks of video data. Motion vectors, other than those which provide direction to co-located blocks in other frames, are determined to be candidates for conversion to vectors which do provide direction to co-located blocks. However, conversion is precluded if the vector is determined to be correlated with one of the neighboring motion vectors.
In a compressed motion picture signal expander, if the compressed motion picture signal includes an uncorrectable signal error, the resulting defective picture block can be replaced by a replacement picture block that blends in smoothly with the picture blocks surrounding it. Hence the picture error resulting from the uncorrectable signal error is concealed. The defective picture block resulting from a signal portion including an uncorrectable signal error is replaced by a replacement block produced by prediction from a past picture using the motion of the past picture. In this manner, the defective picture block can be replaced by the replacement picture block that blends smoothly with the surrounding picture blocks regardless of the existence of motion in the picture. When an uncorrectable signal error is detected, the expander determines whether or not the motion quantity represented by the motion vector of the picture block of the past picture corresponding to the defective picture block is larger than a predetermined value. If the motion quantity is large, the replacement picture block is generated by intra-picture interpolation, using the pixel values of the boundary pixels in the picture blocks surrounding the defective picture block. If the motion quantity is small, the replacement picture block produced by prediction block is used. In this manner, the error resulting from the uncorrectable signal can be concealed and rendered unnoticeable, regardless of the motion quantity represented by the compressed motion picture signal.
