CorridorKey — AI-Powered Green Screen Keying Tool

Introduction

CorridorKey is an open-source tool for extracting clean alpha mattes from green screen footage. It combines traditional chroma keying techniques with machine learning to handle difficult cases like hair detail, semi-transparent objects, and uneven lighting. Created by the team behind Corridor Digital, it brings production-quality keying to anyone with a command line.

What CorridorKey Does

• Extracts foreground subjects from green or blue screen footage
• Preserves fine detail like hair, fur, and transparent materials
• Handles uneven screen lighting and color spill automatically
• Outputs alpha channel video or composited results
• Processes video frames in batch with GPU acceleration

Architecture Overview

CorridorKey uses a hybrid approach combining color-difference keying with a neural network refinement stage. The initial key is generated using standard chroma math, then a lightweight segmentation model refines the edges and handles spill suppression. The pipeline runs on both CPU and GPU via PyTorch, with ONNX export available for deployment.

Self-Hosting & Configuration

• Install via pip with optional GPU support through PyTorch CUDA
• Run from the command line with input/output file paths
• Adjust key color, spill suppression, and edge softness via CLI flags
• Use the Python API for integration into custom pipelines
• Pre-trained models are downloaded automatically on first run

Key Features

• Production-quality edge detail on hair and fine textures
• Automatic spill suppression for green reflections on skin
• Frame-by-frame or batch processing modes
• GPU-accelerated inference for real-time preview
• Exportable alpha matte for compositing in any editor

Comparison with Similar Tools

• DaVinci Resolve — Full editing suite with built-in keyer; CorridorKey is a dedicated CLI tool
• roto-brush (After Effects) — Manual rotoscoping; CorridorKey is fully automated
• Runway — Cloud-based ML removal; CorridorKey runs locally with no subscription
• backgroundremover — General background removal; CorridorKey is specialized for green screen footage

FAQ

Q: Does it work with blue screens? A: Yes. Specify the key color via the --color flag for blue or custom screen colors.

Q: What video formats are supported? A: Any format supported by FFmpeg, including MP4, MOV, MKV, and ProRes.

Q: Can I use it in a video editing pipeline? A: Yes. Output the alpha matte as a separate file and composite in your preferred editor.

Q: Does it require a GPU? A: A GPU speeds up processing significantly but CPU-only mode is supported.

Sources

• https://github.com/nikopueringer/CorridorKey