JVET-Q0806 Integrated Text for GEO [H. Gao, S. Esenlik, E. Alshina, A. M. Kotra, B. Wang (Huawei), R.-L. Liao, J. Chen, Y. Ye, J. Luo (Alibaba), K. Reuzé, C.-C. Chen, H. Huang, W.-J. Chien, V. Seregin (Qualcomm), Z. Deng, L. Zhang, H. Liu, K. Zhang, Y. Wang(Bytedance), J. Li, C. S. Lim (Panasonic), Y.-L. Hsiao, C.-C. Chen, C.-W. Hsu, Y.-W. Huang, S.-M. Lei (MediaTek), L.-F. Chen, X. Li, G. Li, S. Liu (Tencent), L. P. Van, G. Van der Auwera, A. K. Ramasubramonian, H. Huang, W.-J. Chien, M. Karczewicz (Qualcomm), M. Bläser, J. Sauer (RWTH Aachen)] [late]

This contribution was presented in Track B Thursday 16 January at 1225 (chaired by GJS).

Integrated version from adopted proposals JVET-Q0059, JVET-Q0077, JVET-Q0123, JVET-Q0188, JVET-Q0242, JVET-Q0309, JVET-Q0365 and JVET-Q0370.

It was further agreed in the discussion to remove the implementation specific notes in 8.5.7.2.

The related software will be provided with a new upload. Experts are asked further checking the alignment of text and software.

Decision: Adopt JVET-Q0806. Relative to v3, remove notes in 8.5.7.2. This includes all decisions made on JVET-Q0059, JVET-Q0077, JVET-Q0123, JVET-Q0188, JVET-Q0242, JVET-Q0309, JVET-Q0365 and JVET-Q0370.

Test 4-1 in JVET-Q0059 (Huawei, Alibaba, Qualcomm RWTH Aachen)

(a) 82 partition modes in the common base (b) 64 partition modes in test 4-1

Figure: Angles distribution of GEO partitions

In test 4-1, the number of GEO partitions of the common base is reduced from 82 modes to 64 modes. i.e. 20 angles and 4 distances. Comparing to the common base, the angles {5, 7, 17, 19} are removed since in nature video sequences the motion objects are mostly vertical layout and the near horizontal split modes are less frequently used. Besides, the horizontal angles {0, 12} and vertical angles {6, 18} with distance index 0 are removed since these partitioning are overlapped with ternary tree splitting. The total number of geometric partitioning mode can be calculated as 20×3 + 10×3 − 4 − 2 = 64.

Test 4-2.1 & 4-2.2 in JVET-Q0077 (Bytedance)

In test 4-2.1, GEO mode is disabled for a block which width or height is greater than 64.

In test 4-2.2, GEO mode is disabled for a block which width or height is greater than 32.

Test 4-3.1 & 4-3.2 in JVET-Q0062 (Qualcomm, Hikvision)

In test 4-3.1, SBT is disabled for GEO mode.

In test 4-3.2, SBT is disabled for GEO mode when displacement is 0.

Test 4-4 in JVET-Q0060 (Huawei, RWTH Aachen)

In test 4-4 the blending process is turned off for SCC in order to avoid over smoothing the sharp edges of screen contents. A SPS-level control flag and a picture header blending-off flag is introduced to control the blending process on and off.

Test 4-5 in JVET-Q0091 (Nokia)

In test 4-5, the GEO of common base is extended to support 4xN and Nx4 CU. For these CU dimensions, GEO skips wedge_partition_idx syntax, and allows one partitioning angle (either horizontal or vertical) and one distance. For 4xN CU, GEO employs vertical angle blending weights. For Nx4 CU, GEO employs horizontal angle blending weights. Motion vector prediction and blending operation of GEO with a single mode for 4xN and Nx4 CU are aligned with the GEO of common base.

Test 4-6 in JVET-Q0078 (BBC)

An intra predictor and an inter predictor are computed for a block. The inter predictor and the intra predictor are combined using the geometric partitioning scheme as in the common base. The intra predictor is generated as Planar mode and is used in one of the two GEO partitions, and the inter predictor is used in the other GEO partition. The blending scheme as used in GEO is used to blend the two GEO partitions.

There are four candidate GEO partition modes available and the syntax geo_ciip_mode is signalled for indication. The set of the four candidates is adaptively selected based on whether the above and the left neighbouring CU is intra coded or not, using a pre-computed LUT.