Encoder and decoder

An encoder that predictively encodes image data in units of frame, by using a pixel value correlation between frames, including:

• a first predictive coding unit that includes:
• a first data prediction unit for performing a prediction process of predicting image data corresponding to a target frame to be processed, in units of first prediction block being composed of plural pixels, which is obtained by dividing the target frame, thereby to generate first predicted image data;
• and a first data encoding unit for encoding the image data corresponding to the target frame in units of first encoding block that is composed of a plurality of the first prediction blocks, by using first predicted image data corresponding to the first encoding block;
• a second predictive coding unit that includes:
• a second data prediction unit for performing a prediction process of predicting image data corresponding to a target frame to be processed, in units of second prediction block being composed of plural pixels, which is obtained by dividing the target frame, thereby to generate second predicted image data;
• and a second data encoding unit for encoding the image data corresponding to the target frame in units of second encoding block that is obtained by dividing the second prediction block, by using second predicted image data corresponding to the second encoding block;
• and
• a selector for supplying the image data to one of the first predictive coding unit and the second predictive coding unit, in accordance with a instruction signal from outside.

A decoder that predictively decodes coded data which is obtained by predictively coding image data, in units of frame, by using a pixel value correlation between frames, including:

• a first predictive decoding unit that includes:
• a first data prediction unit for performing a prediction process of predicting image data corresponding to a target frame to be processed, in units of first prediction block being composed of plural pixels, which is obtained by dividing the target frame, thereby to generate first predicted image data;
• and a first data decoding unit for decoding coded data corresponding to the target frame in units of first decoding block that is composed of a plurality of the first prediction blocks, by using first predicted image data corresponding to the first decoding block;
• a second predictive decoding unit that includes:
• a second data prediction unit for performing a prediction process of predicting image data corresponding to a target frame to be processed, in units of second prediction block being composed of plural pixels, which is obtained by dividing the frame, thereby to generate second predicted image data;
• and a second data decoding unit for decoding coded data corresponding to the target frame in units of second decoding block that is obtained by dividing the second prediction block, by using second predicted image data corresponding to the second decoding block;
• and
• a selector for supplying the coded data to one of the first predictive decoding unit and the second predictive decoding unit, in accordance with an instruction signal from outside.