A novel 4K video frame interpolator based on bilateral transformer (BiFormer) is proposed in this paper, which performs three steps: global motion estimation, local motion refinement, and frame synthesis. First, in global motion estimation, we predict symmetric bilateral motion fields at a coarse scale. To this end, we propose BiFormer, the first transformer-based bilateral motion estimator. Second, we refine the global motion fields efficiently using blockwise bilateral cost volumes (BBCVs). Third, we warp the input frames using the refined motion fields and blend them to synthesize an intermediate frame. Extensive experiments demonstrate that the proposed BiFormer algorithm achieves excellent interpolation performance on 4K datasets. The source codes are available at https://github.com/JunHeum/BiFormer.

翻译：[translated abstract in Chinese] 本文提出了一种基于双边Transformer（BiFormer）的新型4K视频帧插值器，其执行三步流程：全局运动估计、局部运动细化与帧合成。首先，在全局运动估计阶段，我们在粗尺度上预测对称双边运动场。为此，我们提出了BiFormer——首个基于Transformer的双边运动估计器。其次，我们利用分块双边代价体（BBCVs）高效地细化全局运动场。最后，使用细化后的运动场对输入帧进行扭曲，并将其混合以合成中间帧。大量实验表明，所提出的BiFormer算法在4K数据集上实现了卓越的插值性能。源代码发布于https://github.com/JunHeum/BiFormer。