JVET-X0100 EE2-related: On propagating intra prediction mode for IBC [L.-F. Chen, X. Li, L. Li, S. Liu (Tencent)]
In order to improve the accuracy of the construction of MPM list, intra prediction mode propagation for inter CU was adopted in JVET-W meeting and ECM-2.0 reference software. However, the proposed intra mode propagation is applied on inter CU only. In this proposal, we propose to simply extend the idea to IBC blocks. The overall performance impact of the proposed method on top of ECM-2.0 for SCC content is reported as below.
For Class-F test sequence:
- AI: -0.06%/-0.04%/-0.02% with 100% EncT and 100% DecT
- RA:-0.02%/-0.08%/-0.07% with 101% EncT and 101% DecT
For Class-TGM test sequence:
- AI: -0.05%/-0.08%/-0.01% with 101% EncT and 101% DecT
- RA: 0.00%/-0.06%/-0.04% with 101% EncT and 101% DecT
Only tiny gain (very low for the case of screen content). However, the method is straightforward, does not introduce any impact ob IBC latency, and just uses the same approach to fetch an intra mode from the IBC reference block (using the current block’s vector) as it is otherwise done using the motion vector in the case of inter CUs. This could at most be asserted to make the design more consistent.
No action was taken on this.