Using encoding cost data for segmentation of compressed image sequences

A method of processing compressed digital data derived from a sequence of images, the compressed data being organized as a set of image frames, each image frame comprising a set of blocks, each block comprising a string of bits corresponding to an area of a image frame of the original sequence, comprising the steps of:

• counting a number of bits of a plurality of said strings of bits in the original sequence of images;
• deriving a cost function for each set of strings of bits, said cost function being a value related to the number of bits in each set of strings of bits;
• deriving an auxiliary function from the compressed data, said auxiliary function distinct from the cost function and related to the relationship of the set of image frames;
• and
• applying a temporal segmentation technique to the cost functions in combination with the auxiliary functions associated with at least two images frames;
• identifying at least one image frame.