DiffHDR: Re-Exposing LDR Videos with Video Diffusion Models
Field: Computer Vision Authors: Zhengming Yu, Li Ma, Mingming He Published: 2025-04-08 arXiv: 2504.06259
Abstract (translated)
Most digital videos are stored in 8-bit low dynamic range (LDR) formats, where much of the original high dynamic range (HDR) scene radiance is lost due to saturation and quantization. This loss of highlight and shadow detail precludes mapping accurate luminance to HDR displays and limits meaningful re-exposure in post-production workflows. Although techniques have been proposed to convert LDR images to HDR through dynamic range expansion, they struggle to restore realistic detail in the over- and underexposed regions.
To address this, the authors present DiffHDR, a framework that formulates LDR-to-HDR conversion as a generative radiance inpainting task within the latent space of a video diffusion model. Operating in the Log-Gamma color space, DiffHDR leverages the spatiotemporal generative priors of a pretrained video diffusion model to synthesize plausible HDR radiance in over- and underexposed regions, while restoring the continuous scene radiance of quantized pixels. The framework also supports controllable LDR-to-HDR video conversion guided by text prompts or reference images.
To tackle the scarcity of paired HDR video data, the team developed a pipeline for synthesizing high-quality HDR video training data from static HDRI maps. Extensive experiments demonstrate that DiffHDR significantly surpasses state-of-the-art methods in radiance fidelity and temporal stability, producing photorealistic HDR videos with considerable re-exposure freedom.
Key contributions
- Formalizes LDR-to-HDR video conversion as generative radiance inpainting in a video diffusion latent space
- Log-Gamma color space operation for stable radiance restoration
- Controllable conversion via text prompts or reference images
- Synthetic HDR video training data pipeline built from static HDRI maps
- State-of-the-art results in radiance fidelity and temporal stability
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