Tree based motion compensated video coding

We present a novel technique to encode video sequences, that performs a region-based decomposition of each frame on the basis of motion information. Using the segmentation map, any region in a frame to be encoded will be predicted from a single reference frame, using motion compensated prediction. The use of a single reference frame avoids feedback of the prediction error information in the prediction of successive frames. Coding is simply obtained by describing the segmentation map and the associated motion information. Error information will not be provided for low bit-rate applications. The segmentation map is described using a quadtree structure. Within such a tree structure, we show how motion information can be predicted either spatially or temporally, so as to minimize redundancy of information. The motion and segmentation information are estimated on the basis of a two stage process using the frame to be encoded and the reference frame: (1) a hierarchical top-down decomposition; (2) a bottom-up merging strategy. The proposed posed method is used to encode to encode QCIF video sequences with a reasonable duality at a 10 frame/s rate using roughly 20 kbit/s