Concat

Project Overview

Concat turns raw footage into a finished cut entirely on your machine: import, cutting, captions, voice, background removal, effects and export all sit on one timeline, with no account, no upload and no watermark. The app is written in Rust, composites in the preview on the GPU, and downloads its caption, voice and cutout models once in Settings so it can then work offline. The same project opens across macOS, Windows, Linux and Android.

Item	Value
Type	Non-linear video editor
Platforms	macOS, Windows, Linux, Android
Source version	0.2.10
Interface languages	26
License	AGPL-3.0-or-later

Cutting, captions and voice work all happen on the local disk, with footage never leaving the machine.

Key Features

• Multi-track timeline: stack video, stills and titles on many tracks, with split, trim, ripple delete, merge, freeze frame and speed changes
• Automatic captions: a local Whisper model writes captions at a selectable model size and drops them straight onto the timeline with a style
• Text to speech: built-in local voices, voice cloning from a few seconds of audio, and the system voice on phones
• Background removal: automatic cutout for people or objects, or paint the mask by hand
• Keyframe animation: keyframes for position, scale, rotation, opacity, volume and effect parameters, with a curve editor
• Effects and transitions: 100 effects, filters and transitions, where a transition is a clip of its own that can be moved and trimmed
• Multiple timelines: several cuts in one project, plus picture-in-picture, blend modes, crop and flips
• Captions and titles: adjustable fonts, stroke, shadow and background plate, with presets to start from
• Audio tools: one-click denoise, voice enhance and loudness leveling, plus voice effects
• Export: H.264, HEVC and AV1 up to 4K 60 with 10-bit color, and ProRes 4444 or VP9 with alpha for transparency

Interface and Operation

• Live preview: effects, transitions and keyframes render in the preview window without intermediate files
• Inspector controls: change transform, crop, blend and effect values for the selected clip, with batch edits
• Proxy editing: proxy files for high-bitrate footage keep 4K timelines responsive
• Project lock: an open project folder gets a concat.lock that is released on exit or crash

Automation and APIs

• MCP server: concat --mcp starts the built-in MCP server so an AI client can create projects, import media, issue edit commands and export
• Three modes: --mcp auto is the default, --mcp window reuses an open window, --mcp headless runs without a UI
• API address: set CONCAT_API_ADDRESS such as 127.0.0.1:7420 and CONCAT_API_TOKEN to reach a specific server
• Write scope: headless mode writes only under the home folder unless extra paths are listed in CONCAT_MCP_ROOTS

Target Audience

• Short-form and vertical video creators
• Editors who keep footage local
• Tutorial and screen-recording authors
• Developers scripting an edit pipeline
• Privacy-conscious individual users

Quick Start

1. Pick the package for your platform: setup.exe or .msi on Windows, .dmg on macOS, .deb, .rpm or .AppImage on Linux, .apk on Android
2. On first launch, download the caption, voice and cutout models in Settings; after that the app works offline
3. Drag footage into the media library, then onto the timeline, and cut with the split and trim shortcuts
4. Add keyframes, transitions and titles in the inspector while watching the preview
5. Generate captions on the caption track by picking a model and language, then proofread each line
6. Choose codec and resolution on export: H.264 for compatibility, HEVC for smaller files, AV1 for more savings, and ProRes 4444 for alpha
7. To hand control to a script or an agent, turn on the automation option in Settings and connect with concat --mcp

System Requirements

Item	Requirement
OS	macOS, Windows, Linux, Android
Architecture	Windows x86_64; macOS Intel and Apple Silicon; Linux x86_64 and ARM
GPU	A driver with wgpu support, since preview compositing runs on the GPU
Source build	Rust 1.93 or newer, FFmpeg 7 or newer development libraries, cmake and a C++ compiler

Notes

• Beta status: the app works but still has rough edges, so export a copy before a risky session
• Models download first: caption, voice and cutout models are not in the installer and need one online download
• License terms: AGPL-3.0-or-later, with a commercial license required for closed-source use
• One process per project: a project held by the window or a headless process is refused until the holder closes it