Non-square quadtree transform structure for HEVC

A new non-square quadtree transform structure is proposed to improve the coding efficiency of the HEVC video coding algorithm. The proposed method, designed for non-square inter prediction blocks, incorporates non-square transforms with the residual quadtree transform (RQT) structure. It improves the transform structure adaptation to complex image contents through exploiting the directional features and contours, breaking the limitation of the RQT structure when meeting with the directional scenarios. Through the test, both of satisfied subjective and objective performance improvement can be achieved and there is nearly no implementation cost and no encoding time increase of the proposed method.