Variable Frame Rate for Very Low Bit-Rate Video Coding

Motion description of objects time evolution is often bit-rate wasting even if computed at a low fixed ffame rate. Bit-rate reduction can be achieved taking advantage of the inactivity periods: in such time intervals there is no need for motion coding, as an accurate description of the scene can be obtained only considering the frame diflerence information. We propose to estimate the motion between couples of ffames of the sequence only when the detected activity is high. The possibility of achieving very low bit rate values resides in the ability of dealing with precise motion estimators. To this end we propose here use of a modijied Block Matching algorithm, the slicedBMA, applied on separate sub-sets of each macroblock. Experimental results with test video-sequences show a noteworthy gain together with object segmentation and tracking capabilities.