Extension of Semi-Decoupled Partitioning in Inter Frames

The Alliance for Open Media (AOMedia) has been exploring new coding tools to enhance AV1 capabilities. Semi-Decoupled Partitioning (SDP), originally designed for intra frames in research-v2.0.0, improves coding by decoupling luma and chroma block partitioning. This study extends SDP to inter frames by introducing intra region coding, where the root node is explicitly signaled in the bitstream. Within the intra region, luma components of the intra-coded blocks can be further split, while chroma components remain unsplit. The experiments are implemented on the 8^th anchor, research-v8.0.0, of AVM reference software with CTCv7, and experimental results show that the proposed method can achieve 0.12%, 2.39%, 2.58% coding gain for Y, U, and V component separately with random access configuration and 5% encoding time increase and almost no decoding time increase.