The green beast has been slain, says the README, and it's not wrong

What it does CorridorKey 2.0 is a machine-learning matting model that separates foreground subjects from background in video — no green or blue screen required. It runs two stages: stage 1 processes overlapping temporal windows (Hann windows) to build context, stage 2 streams full-resolution predictions from those combined hidden states. It builds on three frozen foundation models — NVIDIA’s C-RADIOv4-SO400M, Microsoft’s MoGe-2, and Google DeepMind’s RVM small — with weights fetched from Hugging Face. Native resolution is always preserved; the model pads internally and crops back.

The interesting bit The hint system is the clever part. You can run it blind (model picks the subject), give it a single first-frame matte, or feed a full hint video — and a --hint_quality value tells the model how much to trust each hint, from 0.95 for artist-quality mattes down to 0.5 for loose scribbles. Carried hints let the model’s own overlapping-window predictions feed back as guidance, trading control for temporal stability.

Key highlights

• No-hint, first-frame-hint, and full-hint-video inference modes with tunable hint trust
• Automatic Hann window sizing based on free VRAM and clip resolution (80/40 down to 1/1)
• HDR EXR output in scene-linear RGB, preserving values above 1.0 and negatives
• Despill strength control and optional linear-light cutout for VFX pipelines
• Free for commercial and personal use; a paid plugin for common media software exists separately

Caveats

• Requires an NVIDIA RTX 30-series or newer GPU; 4 GB VRAM for 1440p, 6 GB for 4K, plus ~5 GB of weights
• No-hint mode can pick a different subject than you intended; full hints can inherit the hint’s systematic bias
• 96/48 windows were unstable at native 4K even on a 96 GB card, and 80/40 used most of that card’s VRAM

Verdict VFX artists and Python tinkerers who want ML keying without a chroma setup should absolutely try this. If you’re on AMD/Apple silicon or want a turnkey tool, the paid plugin (or something else) is your route.