Rate-Distortion Optimization in Video Coding: from Local to Global

The past decades have witnessed great advancement of video coding techniques and their wide applications in video storage and communications, where rate-distortion optimization (RDO) plays a crucial role to maximize coding efficiency in video coding. In the current blockbased hybrid video coding framework, the RDO is typically performed on the block level individually and independently, which is far from being optimal as it ignores the strong spatialtemporal dependency. However, a global RDO problem becomes so complex that the processing of each coding unit is dependent and entangled with each other due to the extensive use of spatial-temporal predictions in video coding. In the talk, I will discuss the challenges of achieving global RDO in one-pass video coding and present our recent work considering the temporal dependency on top of the video coding standards H.264/AVC and HEVC, respectively.