Projection Deformation Based Motion Compensation For Panoramic Video

For these multi-face projection formats of panoramic video, such as cube map projection format, projection on different faces of a rigid object may change in size and shape when it moves across planes. If a reference block of the current block is out of the range of the current face, projection deformation based motion compensation is proposed. Different with the conventional block-matching motion compensation, the matching block in the reference frame is allowed to be deformed for better motion compensation. Taking parallelizability into consideration, the proposed motion compensation method is applied to each sub-block of the current block. Deformation of reference block is reflected in the relative location of reference sub-blocks while each sub-block still sticks to the translational motion model. Projection deformation based motion compensation is embedded into HM16.15 and achieves BD rate reductions of 0.9% for sequences with relatively rough motions.