JVET-K0275 Non-CE9: DMVR without Intermediate Buffers and with Padding [S. Esenlik, I. Krasnov, Z. Zhao, J. Chen (Huawei)]
A decoder side motion vector refinement (DMVR) method using bilateral matching is proposed, where the intermediate interpolation operation before calculation of MRSAD cost function is removed. Moreover the final prediction is obtained using padding in order to eliminate the additional the memory bandwidth requirement.
According to the proposal when the maximum MRSAD computations are restricted to 13, −4.08% luma coding gain with 107%, encoding time and 126% decoding time over VTM Anchor (RA), and −0.91% luma coding gain with 101%, encoding time and 99% decoding time over BMS Anchor (RA) is achieved.
The proposal targets the memory bandwidth problem (which is particularly more severe for bilateral matching) by applying padding. Further, integer samples are used, which reduces the computational complexity as well.
No refined motion vectors are used from spatial neighbours. Refined MVs are used for deblocking and temporal prediction, which does not cause a latency problem.
Further study in a CE was requested.