Introduction

Ever nailed the perfect take, then realized the lighting is flat, cold, or just wrong for the mood? fal just shipped H3 Max Relight (minimax/h3-max/relight), a video-to-video endpoint built on MiniMax's H3 Max that relights footage you already have. You give it a clip and a lighting sphere, and it hands back the same shot under new light, keeping the subjects, motion, camera move, and even the audio. It's closed and API-only, live today on fal's playground and REST API, priced per second of output.

What H3 Max Relight Does

Relight takes two inputs: a source video of up to 15 seconds, and a sphere render that shows the target lighting, meaning its color, direction, and how soft the shadows fall. Under the hood, the model describes your scene, reads the light off that sphere, and regenerates the whole clip with that lighting while keeping the setting and performance intact.

You don't have to build the sphere yourself. fal's playground includes a built-in Lighting studio where you pick light colors, orbit each light around the subject, and dial in intensity and softness. That turns a fiddly VFX job into something closer to moving lamps around a tiny virtual set.

The specs

  • Input: video up to 15s (mp4, mov, webm, m4v, gif) plus one lighting-sphere image
  • Frame handling: source is converted to 24 fps and trimmed to the nearest 17n+5 frame count, with a minimum of 56 frames (about 2.3s); output matches that length
  • Resolution: 480p and 768p (default) render natively; 1080p and 2K (1440p) are refined from 768p with latent upscaling
  • Aspect ratios: adaptive, 21:9, 16:9 (default), 4:3, 1:1, 3:4, 9:16
  • Preserved: subjects, setting, motion, camera, and audio
  • Extras: optional seed for reproducibility; safety checker on by default

Pricing

Billing is per second of generated video, which equals your source length:

  • 480p costs $0.05/s
  • 768p costs $0.08/s
  • 1080p costs $0.16/s
  • 2K costs $0.32/s

A 5-second clip at the default 768p comes to $0.40, so iterating on a lighting idea is cheap before you commit to a 2K final.

How to Run It Today

The easiest path is the H3 Max Relight playground on fal: drop in a clip, shape your lights in the Lighting studio, and render. If you'd rather script it, here's the minimal API call (swap in your own video and sphere URLs):

curl --request POST \
  --url https://fal.run/minimax/h3-max/relight \
  --header "Authorization: Key $FAL_KEY" \
  --header "Content-Type: application/json" \
  --data '{
    "video_url": "https://your-host.com/source-clip.mp4",
    "reference_image_url": "https://your-host.com/lighting-sphere.png",
    "resolution": "768P",
    "aspect_ratio": "adaptive"
  }'

Python fans can use fal_client.subscribe("minimax/h3-max/relight", arguments={...}) with the same fields.

Where it fits

Relight joins a growing H3 Max editing shelf on fal that already lists Recast, Extend Video, Insert Video, Camera Controls, and Director. Picture the workflow: generate or shoot a clip, swap the background, then relight the whole thing so the subject finally belongs in the new scene. That last step is usually where composites fall apart, and it's exactly what this endpoint targets.

A few practical tips:

  • Start at 768p to judge the light, then re-run at 1080p or 2K with the same seed for the keeper.
  • Use adaptive aspect ratio for vertical or odd-sized footage so nothing gets cropped.
  • Keep sources tight; anything over 15 seconds needs to be split first.

Original Source

Conclusion

Relighting used to mean reshoots or hours of careful grading and roto. H3 Max Relight squeezes it into one sphere image and one API call, with motion and audio left untouched. It's a small endpoint with a big creative lever, especially for anyone compositing AI video into new worlds.

Want to dream up the source clip first? Try MiniMax H3 on Gen → https://artrealmai.com/gen?utm_source=magazine&utm_campaign=gen&utm_content=h3-max-relight-fal-video-relighting

—Aurelia ♡