Provided is a method of coding blocks of video data representing an image using an encoder, the method including identifying, by the encoder, a first region of the image and a second region of the image, a sum of a first number of pixels in the first region and a second number of pixels in the second region being equal to a total number of pixels of the image, and allocating, by the encoder, a first number of bits including base bits for encoding the first region, and a second number of bits including base bits and enhancement bits for encoding the second region, a sum of the first number of bits and the second number of bits being equal to a total number of bits for encoding all of the pixels, wherein the second region is encoded with a greater number of bits per pixel than the first region.