Compound Split Tree for Video Coding

During the exploration of video coding technology for potential next generation standards, the Joint Video Exploration Team (JVET) has been studying quad-tree plus binary-tree (QTBT) partition structures within its Joint Exploration Model (JEM). This QTBT partition structure provides more flexibility compared with the quad-tree only partition structure in HEVC. Here, we further consider the QTBT structure and extended it to allow quad-tree partitioning to be performed both before and after a binary-tree partition. We refer to this structure as a compound split tree (CST). To show the efficacy of the approach, we implemented the method into JEM7. The method achieved 1.25%, 2.11% and 1.87% BD-bitrate savings for Y, U and V components on average under the random-access configuration, respectively.