JVET-M0255 AHG11: MMVD without Fractional Distances for SCC [H. Liu, L. Zhang, K. Zhang, J. Xu, Y. Wang, P. Zhao, D. Hong (Bytedance)]
In the merge with motion vector difference (MMVD) mode, fractional distances including 1/4-pel and 1/2-pel are included in the distance table. However, fractional distances maybe inefficient for screen contents. To address this issue, this contribution proposes to disable fraction distances adaptively in MMVD mode. When fractional distances are disabled, distances in the default table are all multiplied by 4. Simulation results reportedly show 0.76% and 1.66% luma BD-rate saving on SCC sequences in Random Access configuration and Low Delay B configuration respectively. When CPR is off, 1.58% and 2.74% luma BD-rate saving on SCC sequences are achieved in Random Access configuration and Low Delay B configuration respectively.
More related to MMVD (not SCC). A similar approach was investigated in CE 4.4.5b (see remarks there), where switching to an integer table was proposed for UHD resolution.
This contribution was initially discussed Friday 11 January afternoon in Track B; discussion was then moved to CE4 BoG (see JVET-M0843).
Notes from BoG report review: -1.58%/-2.74% in SCC (TGM class) tests with CPR off, -0.76%/-1.66% with CPR on, one slice level flag indicates whether distance is full-pel. It is further pointed out in the Track B dicussion that it was demonstrated to provide benefit for UHD when such an option is available (see under CE 4.4.5). A version shall be used that just multiplies the current MVD distances by 4.
JVET-M0255 AHG11: MMVD without Fractional Distances for SCC [H. Liu, L. Zhang, K. Zhang, J. Xu, Y. Wang, P. Zhao, D. Hong (Bytedance)]
In the merge with motion vector difference (MMVD) mode, fractional distances including 1/4-pel and 1/2-pel are included in the distance table. However, fractional distances maybe inefficient for screen contents. To address this issue, this contribution proposes to disable fraction distances adaptively in MMVD mode. When fractional distances are disabled, distances in the default table are all multiplied by 4. Simulation results reportedly show 0.76% and 1.66% luma BD-rate saving on SCC sequences in Random Access configuration and Low Delay B configuration respectively. When CPR is off, 1.58% and 2.74% luma BD-rate saving on SCC sequences are achieved in Random Access configuration and Low Delay B configuration respectively.
More related to MMVD (not SCC). A similar approach was investigated in CE 4.4.5b (see remarks there), where switching to an integer table was proposed for UHD resolution.
This contribution was initially discussed Friday 11 January afternoon in Track B; discussion was then moved to CE4 BoG (see JVET-M0843).
Notes from BoG report review: -1.58%/-2.74% in SCC (TGM class) tests with CPR off, -0.76%/-1.66% with CPR on, one slice level flag indicates whether distance is full-pel. It is further pointed out in the Track B dicussion that it was demonstrated to provide benefit for UHD when such an option is available (see under CE 4.4.5). A version shall be used that just multiplies the current MVD distances by 4.