with intelligent differential quantization , a video codec intelligently quantizes video at differing strength levels within a frame , such as on a macroblock or a group of mb basis . this allows the codec to control bit usage on a finer granularity than a frame to meet hardware constraints , as well as providing perceptual optimization by coarsely quantizing unimportant regions , while finely quantizing important regions within a frame . the intelligent differential quantization uses motion information gathered from encoding and analysis of the video to classify the importance of different regions of the image , and quantizes the regions accordingly . in addition , the intelligent differential quantization include efficient signaling of information as to the differential quantization strengths in the compressed bit stream .