This is a submission for the Hacktoberfest Open-Source AI Challenge Week 4: Ghost in the Machine
"I'm not scary. I just follow your cursor around and take notes." - Booya
What I Built
Meet Booya, a little ghost that lives in your cursor and makes your screen recordings look like you planned them.
Booya used to be the arrow you forget is there. After years of watching people fumble through demos, re-record the same take six times and squint at tiny buttons, it decided to stick around and help. Now it haunts your cursor on purpose.
Booya is a free, open source, local-first screen recorder for macOS, Windows and Linux. You hit record, do your thing, and Booya quietly:
- Zooms in where the action is. It's patient. One stray click is just a click. When three clicks bunch up close together, or you start typing for a bit, it leans in with a soft spring zoom. When you scroll, it eases back out so you can see the whole page.
- Writes your captions offline. Speech is transcribed on your own machine with Whisper, so captions show up without a single byte leaving your laptop.
- Blinks once when recording starts and once when it stops, so you always know it's awake.
It also does the polish you'd expect from a paid tool: camera bubble and layouts, device frames, motion blur, background music that ducks under your voice, and touch screen support.
Why a ghost? Because the best editing is the kind nobody notices. It's the hand you can't see moving the camera. That felt like exactly what this week's theme was asking for.
Demo
Download for Mac, Windows or Linux from the v0.7.0 release.
Code
booya
Record it. Booya.
Booya is a free, open source screen recorder for product demos, for Windows, macOS and Linux. It does what Screen Studio does (zoom in on clicks, smooth the cursor, put the video on a styled background) but runs on your own computer. There is no account and no telemetry. By default the only network use is downloading the optional models when you ask for them. Cloud providers and uploads exist but stay off until you turn them on.
While you record, Booya writes the cursor, clicks and key presses to a file next to the video. The editor uses that file to zoom on the right spots, draw a clean cursor and show key presses. Export to MP4, WebM or GIF up to 4K in 16:9, 9:16 or 1:1.
Screenshots of the app in this README come from the real interface running in a browser against…
How I Built It
- Open-weight speech model: OpenAI's Whisper weights running locally through whisper.cpp. Booya loads the model on device and turns your narration into word-timed captions. I had to add a timing repair pass, because when you talk fast Whisper sometimes squeezes words into impossible timestamps and whole sentences would quietly vanish. Now the ghost catches them.
- The zoom brain: this part is deliberately not a black box. Booya records clicks, keys and scrolls alongside the video, then a small Rust engine decides where the "interesting" moments are. Three clicks within roughly a fifth of the screen and 4.5 seconds triggers a zoom, typing bursts count too, and there's a cooldown so it never makes you seasick. It's all readable, tweakable code.
- App: Tauri 2 with a Rust core, plus ffmpeg for capture and export. Native audio capture on Windows (WASAPI) and macOS.
- Gemma (local): after recording, a Gemma model running on device reads the transcript and suggests a title, chapters and a short summary.
- Backboard: Used Backboard API for multiple things and open weight models
- ElevenLabs: if you want, you can switch captions to ElevenLabs speech to text. Whisper stays the offline default, so nothing leaves your machine unless you choose that.
-
Shipping: GitHub Actions builds, tests and signs releases for all three platforms, and the in-app updater checks a signed
latest.json.
Screenshots
Main Screen
Editing Panel
Auto Edit
Editing
Export
Style
Why Does Open Innovation Matter?
Screen recordings are full of stuff you don't want on someone else's server: your inbox in the corner, a customer's name, an API key you forgot to hide. Closed tools usually solve captions by uploading your audio to the cloud. Booya doesn't have to.
Because Whisper is open weight, Booya:
- Works with the lights and the internet off. Record on a plane and the captions are still there.
- Keeps your voice and your screen on your machine. No account, no upload, no "we may use your data to improve our services".
- Costs nothing to run. No per-minute transcription bill, so it can stay free for students and indie devs.
- Can't be taken away. If a service shuts down, its features go with it. Booya is MIT licensed code on your disk, and you can swap in a bigger or smaller Whisper model whenever you like.
A closed API would have been faster to wire up on day one. It would also have made Booya just another app that needs the internet to understand you.
The Spirit of It
The moment it landed for me was rewatching a demo where I'd mumbled through the middle part. The captions caught the sentence I didn't even remember saying, and the zoom slid in right where I'd clicked through a form, like someone had edited it while I wasn't looking.
Which, to be fair, someone had.
"You did the demo. I'll just make it look like you planned the zooms." - Booya
Prize Categories
- Best Use of GitHub Copilot: the whole project is automated with GitHub Actions, from CI on three operating systems to signed cross-platform releases and updater manifests.
- Best Use of Gemma: Gemma runs locally to turn each recording's transcript into a title, chapters and a summary.
- Best Use of Backboard: Used Backboard API for multiple things and open weight models
- Best Use of ElevenLabs: an optional ElevenLabs speech to text mode for captions, plus the demo narration. Also used for demo video narration.
Boo is for scaring people. Booya is for when the take actually worked. 👻
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