HorizonRelight: Relighting Long-horizon Videos Consistently via Diffusion Transformers

Diffusion-based video relighting enables controllable relighting from a single input video, but modern video diffusion backbones are trained on short clips and applied to long-horizon videos through chunked sliding-window inference, often causing temporal discontinuities at chunk boundaries. We address this by reframing long-horizon relighting as temporally conditioned latent domain 38 translation. Our framework enforces cross-chunk continuity by propagating targetdomain latents across boundaries and makes this behavior learnable using masked target-domain self-conditioning, training the model to continue from temporally masked propagated context. We further introduce warm-start prompting with a relit prompt anchor from a controllable generative model, which establishes the initial target-domain state and creates a general interface for prompt-based relighting. Experiments on in-the-wild long-horizon videos show markedly improved temporal consistency, with chunk-boundary artifacts largely reduced and unwantedappearancechangesacrosschunksgreatlysuppressed.Visitourwebpage at https://research.nvidia.com/labs/sil/projects/horizonrelight/.