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13th Meeting: Marrakech, January 2019 2019-01-03 03:33
CE2: Affine sub-block size restrictions (Test 2.4.4)
Authors: Huanbang Chen Huawei Timofey Solovyev Huawei Hyeong-Gyun Yang Huawei Jie Chen Huawei
Abstract
This contribution presents the simulation results of affine sub-block size restrictions. These restrictions reduce the worst case of memory bandwidth in motion compensation. For uni-prediction 4x4 sub-block size is used. For bi-prediction four options are tested:
Meeting Notes
JVET-M0472 CE2: Affine sub-block size restrictions (Test 2.4.4) [H. Chen, T. Solovyev, H. Yang, J. Chen (Huawei)]

In affine mode, different sub-block shapes are used, which depends on the prediction direction and the CU size, as shown in the table below.

  1. For uni-prediction affine coded CU, the sub-block size is set equal to 4x4.
  2. For bi-prediction affine coded CU, and if the width of the CU is larger than or equal to its height, the sub-block size is set equal to 8x4;
  3. For bi-prediction affine coded CU, and if the width of the CU is smaller than its height, the sub-block size is set equal to 4x8;

Prediction direction and CU size

Sub-block size

uni-prediction

4x4

bi-prediction, CU width >= CU height

8x4

bi-prediction, CU width < CU height

4x8

Affine sub-block restrictions:

  1. 8x4 for BI, 4x4 for UNI
  2. 4x8 for BI, 4x4 for UNI
  3. Adaptive 8x4/4x8 for BI, 4x4 for UNI
  4. 8x8 for BI, 4x4 for UNI
References:
JVET-L1010 JVET-L1024
Cited:
JVET-M0005 JVET-M0022 JVET-N0323
PATENTS:
CN114467118A 0.34 2022-05-10 EP3928522A1 0.32 2021-12-29 WO2021061023A1 0.30 2021-04-01 CN114467115A 0.28 2022-05-10 US12587688B2 0.28 2026-03-24 WO2020244536A1 0.27 2020-12-10 CA3152435C 0.26 2025-11-04 US12113986B2 0.25 2024-10-08
ARCHIVE v1 :
JVET-L-CE2.4.4.a.XLSM JVET-L-CE2.4.4.b.XLSM JVET-L-CE2.4.4.c.XLSM JVET-L-CE2.4.4.d.XLSM JVET-M0472.docx
Decisions
8x8 for BI, 4x4 for UNI
Citation