Video Coding Using Multihypothesis Motion Compensation in the Redundant Wavelet Domain

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ABSTRACT0310864James E. FowlerMississippi State UIn video coding, multihypothesis motion compensation (MHMC) forms a prediction composed of multiple motion-compensated hypothesis predictions in an effort to combat the uncertainty inherent in the motion-estimation process. MHMC techniques---such as those that choose predictions that are diverse spatially (e.g., fractional-pixel prediction), as well as those exploiting temporal diversity (e.g., bidirectional prediction)---have formed an integral part of modern video coders. This research investigates a new form of MHMC---redundant wavelet multihypothesis (RWMH)---which performs motion compensation in the domain of an overcomplete, or redundant, wavelet transform in order to produce motion-compensated predictions that are diverse in transform phase. The redundancy of the transform yields distinct phases that view motion from different perspectives with each phase contributing its own hypothesis as to the true nature of the motion, resulting in rate-distortion performance significantly superior to traditional single-phase systems.The present research focuses on the incorporation of RWMH into modern video-coding systems in order to demonstrate that the RWMH technique functions complementary to other advanced video-coding techniques. Specifically considered is the incorporation of RWMH into a traditional hybrid system consisting of motion-compensating prediction, transform, and quantization, namely the state-of-the-art H.264 reference model. Additionally, RMHW is deployed into modern 3D coders employing motion-compensated temporal filtering (MCTF) in an effort to provide full temporal, resolution, and fidelity scalability. In both systems, RWMH has the benefit that lower-resolution information is predicted with a greater number of hypotheses, corresponding to the greater difficulty inherent in estimating motion at low spatial resolution. Broader impacts of the work stem from the fact that all resulting source code is provided to the video-coding community as part of a large library under an open-source license.