Velocut

A local video editor and 3D studio that runs in Chrome or Edge, keeps rendering in your browser, and lets Codex edit alongside you.

Velocut is a local video editor and 3D scene studio for creators who want to edit manually or delegate work to Codex. Both work on the same project, with a shared undo history.

Timeline editing: Arrange multiple tracks, trim clips, change playback speed, add transitions and mix audio with volume keyframes.
Titles and motion: Add editable text, captions, effects and motion graphics, with transform keyframes to animate movement.
3D scenes: Compose shots with geometry, GLB models, characters, materials, lights, physics and cameras.
Reviewable AI edits: See who made each change, undo it or branch from an earlier state; revision checks reject AI edits based on an outdated scene.
Optional video generation: Use external services such as MiniMax and Seedance to create clips from text or a first frame, preview candidates and place a chosen result in the timeline. Generation requires your provider account, and saved jobs resume after a project reload.

Media storage, rendering, projects and edit history stay in your browser. AI observations and optional cloud features send relevant data to your chosen model or provider. The Codex integration uses the model running in Codex; the separate optional built-in Assistant requires an Anthropic-compatible provider. Manual editing and the Codex integration need no additional model API key.

Velocut is open source under the MIT license. It requires Node.js and Chrome or Edge with WebGPU and WebCodecs. The full editor doesn't support Safari or Firefox. MP4 export runs in the browser, and available codecs depend on browser support.