JVET-R0223 AHG16: On DMVR and wraparound motion compensation [J. Luo, J. Chen, Y. Ye (Alibaba)]
In VVC draft 8, when wrap around motion compensation is enabled, the bilinear interpolation in DMVR motion search process also uses wrap-around clipping operation. In this contribution, it is proposed to apply regular clipping operation during DMVR motion search, and apply wrap-around clipping operation only for regular interpolation during the final motion compensation process. It is asserted that this simplifies the motion search process in DMVR. Experiment results reportedly show that the BD rate difference is -0.01%, -0.01%, -0.02% for end-to-end WS-PSNR for Y, U and V respectively. Informal subjective viewing was conducted and no visible difference was observed.
Results with 360 video PERP.
It was commented that the implementation seems to become more complicated, as an additional reference area fetch would become necessary for DMVR.
No action was taken on the proposal.
There is another aspect in the proposed text that the DMVR text could be simplified, e.g. in terms of that the combination with RPR would never be used. Decision: Editorial improvement left to editor. (Initial recommendation of AHG meeting was later converted into Decision in track B)