JVET-L0139 CE3-related: Simplified MDMS [J. Choi, J. Heo, S. Yoo, L. Li, J. Choi, J. Lim (LGE)]
This contribution proposes a simplified MDMS. In this method, chroma intra candidate modes are derived from the simplified DM point searching and the reduced number of context models is used in the binarization of chroma intra modes, compared to the JEM MDMS.
Experimental results with 5 chroma modes show -0.09%, -0.97%, and -1.00% BD rate on Y, Cb, and Cr components, respectively, compared to VTM2.0.1 in All Intra configuration, and 0.00%, -0.83%, and –1.00% BD rate, compared to VTM2.0.1 in Random Access configuration.
Experimental results with 3 chroma modes show -0.09%, -0.30%, and -0.31% BD-rates on Y, Cb, and Cr components, respectively, compared to VTM2.0.1 in All Intra configuration, and 0.03%, -0.30%, and -0.31% BD-rates, compared to VTM2.0.1 in Random Access configuration.
Complexity-wise, much less than MDMS in BTM, but the luma gain over VTM drops from 0.2% to 0.1%, whereas the chroma gain stays similar (around 1%). Complexity in operation count not much higher than VTM. See the table below.
Max number of Luma DM point to access | Max number of neighbours to access | Max layers of if conditions | Max number of comparison operator | Max number of logical operators | Max number of assignment operators | ||
VTM2 | 1 | 0 | 1 | 4 | 0 | 9 | |
MD MS | 5 | 5 | 4 | 39 | 28 | 80 | |
5 mode | 2 | 0 | 3 | 5 | 1 | 18 | |
3 mode | 2 | 0 | 2 | 3 | 1 | 13 |
Max number of increments | Max number of bit operation | Number of Context modeling for MPM coding | number of full RDO checks | Has LUT? | LUT size | ||
VTM2 | 0 | 0 | 2 | 6 | N | 0 | |
MD MS | 5 | 2 | 6 | 6 | Y | 68 | |
5 mode | 2 | 2 | 2 | 6 | N | 0 | |
3 mode | 2 | 2 | 2 | 4 | N | 0 |
Further study in a CE was planned.