JVET-AC0159 Non-EE2: IBC MBVD list derivation [Z. Zhang, P. Nikitin, H. Huang, V. Seregin, M. Karczewicz (Qualcomm)]

This contribution proposes to derive the IBC MBVD list from the sample positions along the MBVD directions. The MBVD candidates search starts with checking template SAD costs of offsets added to BVP along each direction with the interval of M-pel. The search process repeats around the K candidates having the lowest TM cost with the half interval. The MBVD list is derived when the interval reaches 1-pel, the K candidates with the lowest TM cost are included into the final list.

The proposed method was implemented on top of ECM-7.0 and the test results are as follows:

Max BVD offset=128-pel, direction=4, start search step=8-pel

AI: -0.30% (Y), -0.17% (U), -0.26% (V), 100% (EncT), 99% (DecT) for class F

-0.64% (Y), -0.58% (U), -0.59% (V), 100% (EncT), 100% (DecT) for class TGM

RA: -0.28% (Y), -0.29% (U), -0.21% (V), 100% (EncT), 100% (DecT) for class F

-0.41% (Y), -0.35% (U), -0.24% (V), 99% (EncT), 100% (DecT) for class TGM

Max BVD offset=256-pel, direction=4, start search step=4-pel

AI: -0.73% (Y), -0.62% (U), -0.72% (V), 105% (EncT), 102% (DecT) for class F

-1.10% (Y), -0.98% (U), -1.03% (V), 105% (EncT), 110% (DecT) for class TGM

RA: -0.45% (Y), -0.47% (U), -0.64% (V), 102% (EncT), 99% (DecT) for class F

-0.84% (Y), -0.79% (U), -0.69% (V), 99% (EncT), 99% (DecT) for class TGM

In case of BVD offset 128, the number of searches is almost same as in current ECM.

It was suggested to investigate this in an EE. Reduction of encoder run time should be targeted.