A method for processing a stream of images including the steps of obtaining coding information from the stream of images to determine one or more bitrate/distortion models representative of the bitrate/distortion relationship of the stream of images, determining a set of coding parameters arranged for use to encode a stream of images with the one or more bitrate/distortion models, reformulating the bitrate/distortion relationship into a decoupled relationship arranged to be applied to a subset of the stream of images, and using the decoupled relationship and the set of coding parameters to generate an adaptive quantization parameter for encoding the stream of images with the bitrate/distortion relationship.