Patent ID: 8509551

Claim:
An image decoder that decodes a color image signal in 4:4:4 format based on an input of a bit stream generated by compression-encoding a color image which is formed of a plurality of color components in 4:4:4 format, the color image being compression-encoded in units of regions obtained by dividing the color image into predetermined regions, the image decoder comprising: a header analyzing unit that extracts inter-prediction common use identification flag from the bit stream; a decoding unit that decodes a motion vector included in the bit stream for each of the regions, and decodes a prediction error signal of each of the regions; a predicted-image generating unit that generates a predicted image on the basis of the decoded motion vector; and an adding unit that generates a decoded image by adding the decoded prediction error signal and the predicted image, wherein the decoding unit decodes, in a case where the inter-prediction common use identification flag indicates that the regions serving as the units of encoding are respectively encoded by a separate inter prediction mode for respective color components, the separate motion vector for respective color components on the basis of a prediction among the color components.