To enhance the efficiency of compression coding.
In the coder that applies orthogonal transform to a received video signal block to compress the signal, a conversion mode control means 100 selectively receives a transform coefficient obtained through the orthogonal transform or a video signal block that is to be coded at present, discriminates correlation of the received value in lateral and longitudinal directions, applies at first orthogonal transform to the received video signal block in a direction with higher correlation, outputs a transform direction control signal for orthogonal transform in the different direction, and an orthogonal transform means 1000 receives the transform direction control signal from the transform mode control means to conduct orthogonal transform accordingly.
PARK CHEL-SOO
SO JUNKO
