JVET-AK0067 AHG7: Tool-off test results of LFNST extension and NSPT [M. Koo, J. Zhao, J. Lim, S. Kim (LGE)]

In the 36th JVET meeting, tool-off tests for a group of ECM tools with large memory access were requested, including LFNST extension and NSPT. In the last AHG7 BoG meeting, it was pointed out that SW support for disabling each of LFNST extension and NSPT with configuration options is required, which will allow measurement of coding benefit of each relative to VVC. To facilitate this, the merge request for the SW support (i.e. !807: Support for tool-off test control of LFNST extension and NSPT) has been issued the ECM15_AHG7 branch. In this contribution, the BD-rate and complexity changes of the following three tool-off cases over ECM-15.0 are reported below {for Y, U, V, EncT, DecT}:

1. LFNST extension off: VVC LFNST is applied instead of LFNST extension.
   • AI { 0.31%, 0.18%, 0.23%, 100%, 101% }
   • RA { 0.32%, 0.13%, 0.34%, 100%, 101% }
   • LDB { 0.24%, -0.42%, -0.12%, 100%, 100% }
   • LDP { 0.21%, 0.64%, 0.63%, 100%, 100% }
2. NSPT off: LFNST extension are applied to all block sizes.
   • AI { 0.73%, 0.68%, 0.73%, 95%, 100% }
   • RA { 0.49%, 0.38%, 0.45%, 99%, 101% }
   • LDB { 0.39%, -0.55%, -0.02%, 99%, 100% }
   • LDP { 0.42%, 0.29%, 0.40%, 99%, 99% }
3. LFNST extension off + NSPT off: VVC LFNST are applied to all block sizes.
   • AI { 1.71%, 1.51%, 1.68%, 89%, 101% }
   • RA { 1.34%, 0.94%, 1.05%, 96%, 101% }
   • LDB { 0.99%, -0.14%, -0.02%, 98%, 100% }
   • LDP { 1.06%, 0.39%, 0.04%, 98%, 99% }

Results indicate that the on/off implementation is working properly for the purposes of AHG7.

Decision (SW): Adopt JVET-AK0067 flag for LFNST extension off.