# An Efficient Four-Parameter Affine Motion Model for Video Coding

arXiv: https://arxiv.org/abs/1702.06297 · HTML: https://mlsanity.com/paper/1702.06297/

## Key facts

- Cited by 10 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 21 Feb 2017.

## Built on by (most cited first, 10 of 10)

- [CompGS: Efficient 3D Scene Representation via Compressed Gaussian Splatting](https://mlsanity.com/paper/2404.09458/) (2024)
- [USTC-TD: A Test Dataset and Benchmark for Image and Video Coding in 2020s](https://mlsanity.com/paper/2409.08481/) (2024)
- [Object Segmentation-Assisted Inter Prediction for Versatile Video Coding](https://mlsanity.com/paper/2403.11694/) (2024)
- [Offline and Online Optical Flow Enhancement for Deep Video Compression](https://mlsanity.com/paper/2307.05092/) (2023)
- [Uniformly Accelerated Motion Model for Inter Prediction](https://mlsanity.com/paper/2407.11541/) (2024)
- [Prediction and Reference Quality Adaptation for Learned Video Compression](https://mlsanity.com/paper/2406.14118/) (2024)
- [Motion-Plane-Adaptive Inter Prediction in 360-Degree Video Coding](https://mlsanity.com/paper/2202.03323/) (2022)
- [CNN-based Prediction of Partition Path for VVC Fast Inter Partitioning Using Motion Fields](https://mlsanity.com/paper/2310.13838/) (2023)
- [Light-weight CNN-based VVC Inter Partitioning Acceleration](https://mlsanity.com/paper/2312.10567/) (2023)
- [IVCA: Inter-Relation-Aware Video Complexity Analyzer](https://mlsanity.com/paper/2407.00280/) (2024)

## Abstract (arXiv)

In this paper, we study a simplified affine motion model based coding framework to overcome the limitation of translational motion model and maintain low computational complexity. The proposed framework mainly has three key contributions. First, we propose to reduce the number of affine motion parameters from 6 to 4. The proposed four-parameter affine motion model can not only handle most of the complex motions in natural videos but also save the bits for two parameters. Second, to efficiently encode the affine motion parameters, we propose two motion prediction modes, i.e., advanced affine motion vector prediction combined with a gradient-based fast affine motion estimation algorithm and affine model merge, where the latter attempts to reuse the affine motion parameters (instead of the motion vectors) of neighboring blocks. Third, we propose two fast affine motion compensation algorithms. One is the one-step sub-pixel interpolation, which reduces the computations of each interpolation. The other is the interpolation-precision-based adaptive block size motion compensation, which performs motion compensation at the block level rather than the pixel level to reduce the interpolation times. Our proposed techniques have been implemented based on the state-of-the-art high efficiency video coding standard, and the experimental results show that the proposed techniques altogether achieve on average 11.1% and 19.3% bits saving for random access and low delay configurations, respectively, on typical video sequences that have rich rotation or zooming motions. Meanwhile, the computational complexity increases of both encoder and decoder are within an acceptable range.