README.md

metadata

title: Video Replace Background
emoji: 🎬
colorFrom: indigo
colorTo: green
sdk: gradio
sdk_version: 6.29.1
app_file: app.py
pinned: false
short_description: replace video background with LTX alpha LoRA + H3 inpainting
suggested_hardware: zero-a10g

Subject on a New Background

Put a video subject on a new, generated background, by chaining two models:

1. Lift the subject with the LTX-2.5 Alpha-Gen matte LoRA (hugging-apps/ltx-2-5-alpha-matte), called over the gradio API: video in, alpha matte + green-screen out.
2. Regenerate the background with MiniMax-H3 ref2va inpainting, held in this Space. The subject is handed to H3 as conditioning; the inverted matte marks the background as the region to repaint. Text encoding runs on the qwen3vl-conditioner Space, so this one never loads a 60 GiB encoder.

Upload a clip, describe the background, and press Replace background - or click one of the examples. Relight strength is the quality lever: at 0 the subject is held exactly (best when the new background's light matches the original); turn it up and H3 lights the subject into the new scene so it does not read as a cutout, while keeping identity.

Runs on ZeroGPU with the ref2v turbo LoRA at 8 steps. The matte and conditioner calls bill the caller's ZeroGPU quota, same as the denoise.