PRODUCING AND ENCODING RATE-DISTORTION INFORMATION ALLOWING OPTIMAL TRANSCODING OF COMPRESSED DIGITAL IMAGE

A method for encoding rate-distortion information associated with the compression of an input digital image includes the steps of: computing rate and distortion-reduction values associated with each coding pass of each compressed codeblock bit-stream, and encoding rate and distortion-reduction values associated with coding passes contained in the final compressed bit-stream. A method for using encoded rate-distortion information associated with a compressed digital image bit-stream during transcoding of said compressed digital image bitstream includes the steps of: parsing the compressed digital image bit-stream to obtain compressed codeblock bit-streams, decoding the encoded RD information to obtain rate and distortion-reduction values associated with codeblock coding passes, and using such rate-distortion information to optimally transcode such compressed digital image bit-stream to form a new compressed digital image bit-stream at a given bit-rate, resolution, and for given visual weights.