Patent ID: 8189663

Claim:
A method of obtaining a quantisation value for macroblocks of a picture in a video compression system comprising the steps of: a. estimating, in a processor, sizes in the transform domain of each macroblock of a picture in terms of a sum of all coded coefficients for a plurality of quantisation values; b. assuming, in the processor, a relationship between a size of a macroblock and Activity of the macroblock for each quantization value; c. dividing, in the processor, macroblocks into groups by Activity; d. determining, in the processor, an average Activity of each group; and e. calculating, in the processor, a quantisation value for each group from the assumed relationship between a number of bits per macroblock and Activity of the macroblock and the average Activity of the group, wherein the total number of bits available for all of the macroblocks in the coded picture is imposed by a predetermined bit rate of the video compression system.