Video encoder and decoder with improved motion detection precision

摘要

The present invention provides an encoder for encoding image data according to predictive coding including motion detection, which increases motion detection precision while suppressing an increase in the amount of data processed at the predictive coding. This encoder includes a 4x4 block divider 101 for dividing image data corresponding to a target frame to be processed into 4x4 pixel blocks; a motion compensation unit 111 for performing motion compensation for the image data in units of 4x4 pixel block, thereby to generate predicted data; an 8x8 pixel block configuration unit 103 for transforming difference data between image data corresponding to the 4x4 pixel block and predicted data corresponding to the 4x4 pixel block into prediction error data of an 8x8 pixel block. This encoder carries out a DCT process, a quantization process, and a variable length coding process for prediction error data, in units of 8x8 pixel block.