How sparse keyframes and optical flow eliminate AI video restyle flicker

When AI diffusion models restyle video frame by frame, subtle variations between frames create a flickering effect because the model makes independent style choices 24 times per second. A developer has published a detailed technical walkthrough describing a method to eliminate this problem without sacrificing style quality. The approach stylizes only a sparse set of keyframes — selected via scene detection at fixed intervals — and fills the gaps by warping stylized pixels along the optical flow rather than re-running the diffusion model. This ensures temporal consistency because warped frames reuse the same pixels instead of generating fresh, potentially conflicting interpretations. The technique draws on published research including Rerender A Video (SIGGRAPH Asia 2023) and EbSynth (ACM ToG 2019), and the post walks through the supporting code that handles keyframe indexing, file management, and blending.