UltimateSlice

The AI connectable video editor.

UltimateSlice is a Final Cut Pro–inspired non-linear video editor built with Rust and GTK4, powered by GStreamer for media playback and export.

Built in MCP server allows for AI collaboration.

Features

✅ Implemented

• GTK4 application scaffold with dark theme styling
• Media library import with duration probing (video/audio/image)
• Source monitor with playback, scrubber, in/out marks, and timecode
• Timeline with multi-track rows, zoom/pan, clip selection, trim, move, razor
• Undo/Redo command history
• Inspector panel for selected clip properties
• MP4/H.264 export via GStreamer pipeline
• FCPXML 1.10–1.14 import + 1.14 export
• Optional MCP server (--mcp) for JSON-RPC control

Third-Party Crates and Libraries

UltimateSlice uses open-source crates and runtime libraries, including:

• gtk4-rs / gdk4 / gio / glib — LGPL-2.1-or-later
• gstreamer-rs + GStreamer — LGPL-2.1-or-later
• quick-xml — MIT
• serde / serde_json — MIT OR Apache-2.0
• uuid — MIT OR Apache-2.0
• anyhow / thiserror / log / env_logger — MIT OR Apache-2.0
• rustfft — MIT OR Apache-2.0
• ort (ONNX Runtime) / ndarray — MIT OR Apache-2.0
• FFmpeg (tooling/runtime) — LGPL-2.1-or-later (Flatpak build enables GPL options)
• x264 (Flatpak build dependency) — GPL-2.0-or-later

For exact versions and full dependency tree, see Cargo.toml, Cargo.lock, and io.github.kmwallio.ultimateslice.yml.

🔜 Planned

See ROADMAP.md for upcoming features like thumbnails, audio waveforms, multi-track editing, transitions, and a program monitor.

Project Structure

See docs/ARCHITECTURE.md for the full layout and design notes. Highlights:

• src/app.rs – GTK application setup and CSS loading
• src/model/ – core data model (Project, Track, Clip, MediaItem)
• src/media/ – playback, thumbnails, and export
• src/ui/ – GTK widgets (timeline, inspector, media browser, preview)
• src/fcpxml/ – FCPXML parser/writer

Requirements

• Rust (edition 2021)
• GTK4 development libraries
• GStreamer + plugins for playback and export

On Linux, install GTK4 and GStreamer via your distribution packages.

Recommended System Specs

Three tiers targeting up to 4K source media, each with suggested UltimateSlice preference settings.

Minimum (1080p editing, basic 4K with proxies)

Component	Spec
CPU	Dual-core, 2.0 GHz+
RAM	4 GB
GPU	Integrated graphics (Intel HD / AMD APU), 512 MB shared VRAM
Storage	HDD (SSD recommended for proxy cache)

Settings: Proxy Mode → Half or Quarter, Preview Quality → Quarter, Hardware Acceleration → Off, GSK Renderer → Cairo, Playback Priority → Smooth

Recommended (4K editing)

Component	Spec
CPU	Quad-core, 3.0 GHz+
RAM	8 GB
GPU	Integrated or discrete with VA-API support, 2 GB VRAM
Storage	SSD

Settings: Proxy Mode → Off, Preview Quality → Half or Auto, Hardware Acceleration → On, GSK Renderer → Auto (OpenGL), Playback Priority → Balanced

Ideal (4K real-time, multi-track compositing)

Component	Spec
CPU	6+ cores, 3.5 GHz+
RAM	16 GB+
GPU	Discrete GPU with VA-API, 4 GB+ VRAM
Storage	NVMe SSD

Settings: Proxy Mode → Off, Preview Quality → Full, Hardware Acceleration → On, GSK Renderer → Vulkan, Playback Priority → Accurate, Real-time Preview → On

Notes:

• VA-API hardware decoding supports H.264, H.265/HEVC, VP9, and AV1.
• Export uses FFmpeg (CPU-based) — more cores = faster exports.
• Flatpak includes --device=dri for GPU access; native installs need VA-API drivers.

Build & Run

# from the project root
cargo build
cargo run

To run with MCP server enabled:

cargo run -- --mcp

To open a project file at startup from program arguments:

cargo run -- /path/to/project.uspxml

Python MCP Socket Client

When using the MCP socket transport (running instance), you can use the Python bridge client:

python3 tools/mcp_socket_client.py

Optional socket override:

python3 tools/mcp_socket_client.py --socket /tmp/ultimateslice-mcp.sock

The client reads JSON-RPC lines from stdin and writes responses to stdout. See docs/user/python-mcp.md for complete command examples.

Flatpak

A Flatpak manifest is provided at io.github.kmwallio.ultimateslice.yml.

flatpak-builder build-dir io.github.kmwallio.ultimateslice.yml --user --install --force-clean
flatpak run io.github.ultimateslice

Notes

• GTK4 callbacks cannot unwind panics. Avoid RefCell double-borrows in UI callbacks.
• The project shares a single GStreamer playbin for source and timeline playback.

License

This project is licensed under the GNU General Public License v3.0.