FableCut

FableCut is a Premiere-style non-linear video editor that runs entirely in the browser, whose core feature is that the entire timeline is exposed as a JSON document (project.json), so any process capable of writing JSON can edit the video. It provides MCP and REST interfaces, allowing AI agents (such as Claude Code, Claude Desktop, or any tool supporting MCP/REST) to drive editing, while the browser UI hot-reloads within about 150 milliseconds via server-sent events, enabling humans and agents to work together on the same timeline. The project has zero npm dependencies; you only need to run a single node server.js.

Main capabilities include:

• Video and audio tracks (3+4 by default, expandable to 16 each), supporting drag-and-drop, trimming, splitting, snapping, and undo/redo.
• Track solo, mute, targeting, and locking; clip locking, disabling, and unlinking.
• Directly manipulate clips or titles on the monitor: move, scale (corner handles), rotate (top handle, Shift to snap).
• Timeline multi-selection (marquee, Ctrl/Cmd/Shift+click, Ctrl+A, Esc), group move, delete, and split.
• Beat and cue markers (press m during playback to drop one), which can be named, colored, dragged, jumped to, and used as snap targets.
• Transitions (Alt+t to add, drag the triangle to adjust duration).
• Real decoded audio waveforms.
• Mixer: each audio track has a fader, pan, mute, solo, and level meter, and the master fader has a real-time LUFS readout.
• Clip gain, channel mode, normalization (ITU-R BS.1770 loudness or sample peak, target -14/-16/-23 LUFS or -1 dBFS).
• Volume lines, fade in/out, and crossfades (Shift+D).
• Auto-ducking (auto-duck): select the music, dialogue track, and amount, and the music automatically lowers while speech is present.
• Audio effects and presets: EQ, high-pass/low-pass, compressor, limiter, noise gate, delay, reverb, distortion, stereo width, and pitch shift, which can be chained and applied to clips, tracks, buses, and the master output; presets include Clean voice, Podcast, Radio, and more.
• Effect automation: press ◆ next to the effect settings to set a keyframe at the playhead.
• Submix buses: + Bus adds a bus, and tracks can be routed to it.
• Noise reduction: Light/Medium/Strong, use ffmpeg to render the cleaned copy.
• Project media bin folders: tree view, drag to nest, right-click to create a new folder.
• Import from URL: + URL downloads HTTPS video/audio/image to ./media/.
• Audio Hold: when paused, loop one frame of audio at the playhead.
• Canvas aspect ratio presets (16:9, 9:16, 4:5, 1:1), project FPS selection (24/25/30/50/60), safe area guides.
• Export frame/reframe: the composition canvas can be larger than the delivery crop; drag the export frame handles to reframe.
• Program monitor zoom: mouse wheel to zoom, middle-click or Alt+drag to pan.
• Full J/K/L shuttle: L forward, J backward, press repeatedly to speed up, K to stop.
• Type timecode to jump: 01:15:00, 1500, +30, 12.5.
• Adjustable workspace: drag dividers, timeline track density presets S/M/L.
• Zoom to selection (⇧Z).
• IN/OUT work area: i and o to set markers, export range dropdown (entire timeline/IN–OUT).
• Find and close gaps: g jumps to the next shared gap, ⇧G closes the gap.
• Trim tools: select, ripple edit, rolling edit, slip, slide (V B R Y U).
• Lift/extract: ; removes the IN→OUT range and leaves a gap, ' removes and closes the gap.
• Jump to cut points: ↑/↓ move to the previous/next edit point.
• Ripple delete: ⇧Del removes the selection and shifts subsequent clips left.
• Reset properties: Ctrl/Cmd+click an inspector tab or slider to restore defaults and clear keyframes.
• Replace media: the inspector Source button swaps the underlying file while preserving position, trims, keyframes, transitions, and effects.
• Multichannel video audio: videos with more than 2 channels create linked audio clips for each channel, automatically creating additional audio tracks (up to 16).
• 14 one-click filter presets (Cinematic, Teal & Orange, Black, Vintage, Cyberpunk, Sunset, Midnight, etc.).
• Adjustment layer: one clip grades everything below it.
• Color workspace: real-time waveform, RGB parade, vectorscope, histogram, and GPU grading tabs, including lift/gamma/gain/offset wheels, exposure, white balance picker, black/shadows/midtones/highlights/white, log contrast, soft rolloff, saturation, and curves (luma, RGB, hue vs hue, hue vs saturation, hue vs luma, saturation vs luma), with picker-marked colors, and layers (secondary grading): HSL qualifier and/or ellipse, rectangle, polygon, bezier, or freehand masks (featherable, invertible, keyframable, draggable on the monitor), with a mask view.

How to use: run node server.js to start the server, then open the UI in a browser. You can edit manually through the UI, or let an AI agent edit project.json through the MCP/REST interface. Agents can call operations such as fablecut_patch_project, fablecut_auto_duck, fablecut_denoise, fablecut_import_media.

Use cases: scenarios that need AI-assisted video editing, automated video processing, and human-AI collaborative timeline editing.

Limitations: zero npm dependencies, but a Node.js environment is required; some features (such as WebCodecs export) are disabled when setting the export frame; remote SVG is rejected; URLs are not kept as media.src to avoid canvas tainting.