Ultron

Open source game clipping for Windows, built on OBS.

While you play, Ultron points OBS at your game and keeps the last minutes in OBS's replay buffer. Say "Ultron, clip that" and the moment is saved.

• Automatic game capture. Recognises thousands of games, and points OBS's capture and audio at whichever one is running.
• Replay buffer only while you play. Every clip has game footage, and nothing records while you're not gaming.
• Clip by voice. You never take your hands off the game. Recording works by voice too.
• One-click OBS setup. Scene, sources, clip length and audio tracks (one mix, or a separate track per app for editing).
• Local and private. Game detection, the wake word and speech recognition all run on your PC. No account, no upload, no cloud service.
• Light on the game. Below-normal priority, a small speech model, no voice output.

Contents

• Install
• Voice commands
• How it works
• Configuration
• Development
• License

Install

You need: Windows 10 or 11, OBS Studio 28 or newer (opened at least once) and a microphone.

1. Download UltronSetup.exe (or pick a version under Releases) and run it. The installer isn't code-signed, so Windows may say "Windows protected your PC": click More info → Run anyway.

2. Click through the wizard. Leave Set up OBS for me on. It:

   • turns on OBS's WebSocket server and replay buffer (anything already set up is kept)
   • asks for the clip length
   • asks for the scene: a new one (default "Game") or one you already have
   • asks for the audio tracks (see below)
   • adds the Game Capture, Game Window and Game Audio sources

   If OBS is open it asks to close it for a moment. The last page lists every OBS change before anything is installed.

3. Setup downloads Python and the speech model (a few hundred MB, a few minutes).

4. Start a game and say "Ultron, clip that".

Audio track preset	Tracks
Simple	1 mixed track
Editing	1 everything, 2 mic, 3 game; optionally 4 Discord and 5 music
Every app separate	1 everything, 2 mic, 3 game, 4 Discord, 5 music, 6 browser. Desktop Audio is muted, so other programs aren't heard
Custom / Keep	Your own track count, or leave OBS as it is

Track 1 is always the full mix, so clips sound right in any player.

Updates. With Keep Ultron up to date on (the default), Ultron checks this repo's releases every 6 hours and updates itself, but only while no game runs and OBS isn't recording. Then it restarts. Your config.toml is never replaced. Turn it off with auto = false under [update], and new versions are only mentioned in the log.

The Start menu has the settings (config.toml), the log, Restart Ultron (after editing the settings), Repair (download the models again) and Set up OBS again. Uninstall from Settings → Apps; your config.toml is kept.

Upgrading from OBS Game Watcher? The installer offers to remove it, since Ultron does the same job and both would steer OBS at once.

Voice commands

Say the wake word "Ultron", then the command, in one breath or after the tone.

Say	Does
clip that / clip it / save that	Saves the replay buffer (while a game runs)
start recording / stop recording	OBS recording (starting only while a game runs)
pause recording / unpause recording	Pauses and resumes a recording

A rising tone means done, a falling tone means it couldn't (no game running, OBS closed, ...). ultron.log says why. Anything else is ignored: Ultron only controls OBS. OBS's own Save Replay hotkey keeps working too.

The phrases are yours to change under [phrases] in config.toml.

Wake word accuracy. The "Ultron" model (models\wake\ultron.onnx) was trained with openWakeWord on synthetic voices. On voices it never heard in training it catches 97.7% of wake words, with about one false wake per 2.7 hours of other audio. If it wakes by accident, raise threshold under [wake]; if it misses you, lower it.

How it works

1. Every 3 seconds Ultron lists the running programs (straight from Windows, about 1 ms) and matches them against Discord's public list of detectable games, cached and refreshed daily. No Discord login is involved.
2. When a game runs, it points these OBS sources at the game's window, and corrects them if they drift (changed by hand, game relaunched):
   • Game Capture
   • Game Window (Window Capture, underneath): shows games Game Capture can't hook, such as Clickteam games like Five Nights at Freddy's
   • Game Audio (Application Audio Capture): the game's sound on its own track With several games open, it follows the one whose window is in front; while you're on the desktop or Discord it keeps the last game you played.
3. It runs the replay buffer only while a game is running.
4. Optionally it switches scenes when a game starts and stops.

Anti-cheat protected games (VALORANT, for example) hide their file path; those are matched on the executable name alone. A game Discord doesn't know (one you're making, say) goes under extra in [games].

Performance. Ultron runs at below-normal priority, so the game always wins the CPU. Speech recognition (Whisper base.en, 2 CPU threads) runs only after the wake word. Game detection, OBS control and voice share one process.

Configuration

Settings live in config.toml in the install folder. Restart Ultron after editing.

Section	What
[wake]	Wake word model and sensitivity
[audio]	Microphone, tone loudness, when listening stops
[stt]	Speech model and CPU threads
[obs]	OBS WebSocket address (password: the OBS_WEBSOCKET_PASSWORD user environment variable)
[update]	Automatic updates on or off, how often to check
[voice]	Commands that only work while a game runs
[phrases]	What you can say
[watcher]	Source names, poll interval, replay buffer, scene switching
[games]	Programs that aren't games (ignore), games Discord doesn't know (extra)

Development

.\setup.ps1                          # once: uv, Python 3.12, packages, models (kept in this folder)
.\installer\obs-setup.ps1 -CloseObs  # set OBS up (-Check only reports; see the script for options)
.\run.ps1                            # run in the foreground
.\run.ps1 --dry-run                  # show which games are detected right now, change nothing
.\run.ps1 --text --game              # type commands instead of speaking (no game watcher)
.\run.ps1 --no-voice                 # only the game watcher, no microphone

If PowerShell says a script "is not digitally signed", run it as powershell -ExecutionPolicy Bypass -File .\setup.ps1.

• Installer: .\installer\build.ps1 (needs Inno Setup 6). -UiTest builds one that shows every page but never installs.
• Release: .\installer\release.ps1 builds it and publishes a GitHub release, which is what the download link points at.

File	What it does
ultron/__main__.py	Startup, single instance, the listen loop
ultron/games.py	Discord game list and process matching
ultron/watcher.py	Points OBS at the game, runs the replay buffer
ultron/obs.py	The shared OBS WebSocket connection
ultron/voice.py	Wake word, speech recognition, tones
ultron/commands.py	The voice commands
installer/	Setup.exe (Inno Setup), obs-setup.ps1 and the OBS wizard pages

Works well with

• Jarvis: a voice assistant for the rest of your PC (music, volume, apps, questions).

License

MIT. Built on OBS Studio, openWakeWord, faster-whisper and obsws-python.