IMAGE ENCODING METHOD, IMAGE DECODING METHOD, IMAGE ENCODING DEVICE, IMAGE DECODING DEVICE, AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To improve encoding efficiency of encoding even if use of a code amount is restricted at a low rate.

SOLUTION: When bit depth conversion predictive encoding is selected in intra-encoding, a bit depth conversion predictive encoding unit 60 performs bit depth conversion processing on an N-bit image signal for a designated encoding unit to convert the image signal to a low bit depth image of N-Δ bits, performs encoding/decoding processing on the lower layer signal, and performs inverse bit depth conversion processing on the decoded image. Finally, the unit encodes a difference signal between the N-bit image and an input image, and multiplexes the difference signal and the low bit depth image signal to output them as an encoded stream.

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