Videokode- og videodekodeapparat

摘要

An alpha-map encoder constituted of a first down-sampling circuit (21) which encodes alpha-map signals indicating the shape and position in a screen of an object at a reduction rate according to size conversion ratio information, an up-sampling circuit (23) which up-samples a down-sampled alpha-map signal for returning the signal to the original size at an enlargement rate according to the size conversion ratio information and outputs a locally decoded alpha-map signal, a motion compensative prediction circuit (25) which generates a motion compensative prediction signal based on the preceding reproduced image signal, the reproduced image signal of the circuit (21), and a motion vector signal, a second down-sampling circuit (26) which down-samples the motion compensative prediction signal at a predetermined reduction rate, a binary image encoding circuit which encodes the alpha-map signal down-sampled by means of the first down-sampling circuit (21) into a binary image in accordance with the motion compensative prediction signal down-sampled by the circuit (26) and outputs the binary image encoded signal, and a multiplexing circuit which multiplexes and outputs the binary image encoded signal and the information on the enlargement rate. <IMAGE>