Controllable Human-centric Keyframe Interpolation with Generative Prior
Authors: name: Zujin Guo, name: Size Wu, name: Zhongang Cai, name: Wei Li, name: Chen Change Loy

Existing interpolation methods use pre-trained video diffusion priors to
generate intermediate frames between sparsely sampled keyframes. In the absence
of 3D geometric guidance, these methods struggle to produce plausible results
for complex, articulated human motions and offer limited control over the
synthesized dynamics. In this paper, we introduce PoseFuse3D Keyframe
Interpolator (PoseFuse3D-KI), a novel framework that integrates 3D human
guidance signals into the diffusion process for Controllable Human-centric
Keyframe Interpolation (CHKI). To provide rich spatial and structural cues for
interpolation, our PoseFuse3D, a 3D-informed control model, features a novel
SMPL-X encoder that transforms 3D geometry and shape into the 2D latent
conditioning space, alongside a fusion network that integrates these 3D cues
with 2D pose embeddings. For evaluation, we build CHKI-Video, a new dataset
annotated with both 2D poses and 3D SMPL-X parameters. We show that
PoseFuse3D-KI consistently outperforms state-of-the-art baselines on
CHKI-Video, achieving a 9% improvement in PSNR and a 38% reduction in LPIPS.
Comprehensive ablations demonstrate that our PoseFuse3D model improves
interpolation fidelity.