A method and apparatus transcode an image. An encoded input bitstream of the image is analyzed to obtain a structure of the encoded input bitstream, in which the image includes a region-of-interest and a background region, and in which the encoded input bitstream is a stream of packets. A first quality value for the region-of-interest and a second quality value for the background region are determined. An encoded output bitstream is composed from a subset of the packets selected from the encoded input bitstream according to the structure, in which the subset of packets includes a first set of packets corresponding to the region-of-interest having the first quality value, a second set of packets corresponding to the background region and having second quality value, and empty packets.