A minimalist macOS menu-bar app that fixes the color of the Logitech MX Brio (and other UVC webcams) at the sensor level — warm/cinematic presets, manual exposure & focus, and framing, applied to every app at once with no virtual camera.

The MX Brio ships with a noticeably cold/blue, over-saturated image (auto white balance sits around ~4300 K and reads blue). BrioTone drives the camera's real UVC controls to make the picture warmer and more natural — closer to how Apple renders — and turns the webcam into a properly controllable camera with locked exposure, focus, and white balance for a stable, professional look.

Because adjustments are written directly to the camera hardware over UVC, they apply system-wide: Zoom, Google Meet, Microsoft Teams, FaceTime, QuickTime, OBS — all at once, with no virtual-camera layer to install.

• Features
• Requirements
• Install
• Usage
• Cinematic presets
• How it works
• Project structure
• Optional: Apple-style LUT layer (OBS)
• Troubleshooting
• Limitations
• Acknowledgements
• License

Organized into three tabs to keep the popover compact:

• Color — white balance (2800–7500 K) with Auto, saturation, contrast, sharpness, brightness.
• Exposure — the pro upgrade: turn off Auto and lock shutter (shown as 1/x s) and ISO/gain; backlight compensation; anti-flicker (50/60 Hz).
• Framing — auto-focus toggle + manual focus distance, zoom (1×–4× on the 4K sensor), and pan/tilt when zoomed in.

Plus:

• Presets that capture the entire state (color + exposure + framing), including six built in and your own saved looks.
• Apply at login — re-applies your last look on startup.
• System-wide — no virtual camera, no LUT, affects every app simultaneously.

• macOS 14.0+ (built and tested on macOS 26, Apple Silicon).
• A UVC webcam. Tuned for the Logitech MX Brio (046d:0944); other UVC cameras work but exposed controls/ranges vary.
• Xcode / Swift toolchain and git (to build).

git clone https://github.com/johanvillalbab/brio-tone.git
cd brio-tone
./build.sh            # compiles uvc-util + the app, assembles dist/BrioTone.app
open dist/BrioTone.app # a camera icon appears in the menu bar

build.sh uses the bundled uvc-util helper when present. If it is missing, the script compiles it from pinned source. It then builds the Swift package, assembles the .app, and ad-hoc signs it.

To launch automatically: System Settings → General → Login Items → + and add dist/BrioTone.app.

Click the camera icon in the menu bar, then:

1. Pick a starting point from Load preset (e.g. Cine — Cálido or Apple-ish).
2. Fine-tune with the sliders — changes apply live to the camera.
3. Save your own look with ＋ → name it. Presets store color, exposure, and framing.

The one dial to know — ISO/gain. The cinematic presets lock exposure (that's what makes the image stable and professional), so the correct brightness depends on your lighting:

• Image too dark → raise ISO (Exposure tab).
• Image washed out → lower it.
• Keep ISO as low as possible for a clean, noise-free image. That's the golden rule.

All share the same DNA: locked white balance + locked exposure at a 1/60 s shutter (the 180° rule at 30 fps → natural motion blur), low sharpness (kills webcam over-sharpening), and a flatter, graded color base.

Also included: Apple-ish (warm), Neutral, and Logitech (default).

The MX Brio exposes its image pipeline through standard USB Video Class (UVC) controls. BrioTone wraps the uvc-util command-line tool to read and write them (white-balance-temp, saturation, contrast, sharpness, brightness, auto-exposure-mode, exposure-time-abs, gain, auto-focus, focus-abs, zoom-abs, pan-tilt-abs, …).

These are hardware controls on the camera itself, so any app that opens the webcam sees the corrected image — there is no frame processing and no virtual camera. The trade-off: UVC can't do per-color remapping (a 3D LUT), so color is limited to global white balance / saturation / contrast / brightness. For LUT-style grading see the optional OBS layer.

Empirical note: the MX Brio runs cold. On this camera, a higher white-balance value = a warmer image (verified by capturing frames at 2800 K vs 7500 K). The presets lean warm to counter the factory blue cast.

brio-tone/
├── Package.swift              # SwiftPM executable target
├── Info.plist                 # LSUIElement (menu-bar agent) bundle metadata
├── build.sh                   # Builds uvc-util + app, assembles & signs dist/BrioTone.app
├── Sources/BrioTone/
│   ├── BrioToneApp.swift      # @main, SwiftUI MenuBarExtra
│   ├── ContentView.swift      # Color / Exposure / Framing UI
│   ├── AppModel.swift         # Observable state, debounced live apply
│   ├── CameraController.swift # Wraps uvc-util (device discovery, get/set)
│   └── Presets.swift          # CameraState model, built-in presets, persistence
└── obs-apple-look/            # Optional LUT layer (see below)

User presets and last-applied state are stored in ~/Library/Application Support/BrioTone/.

Sensor controls fix coldness/saturation/contrast everywhere. For fine Apple-style skin-tone remapping you need a 3D LUT over a virtual camera. The obs-apple-look/ folder contains a parametric LUT generator (generate_lut.py, numpy) that produces custom .cube files tuned for the MX Brio, plus SETUP.md for loading them in OBS and exposing the OBS virtual camera to Zoom/Meet/Teams.

Don't stack color twice — with the LUT active, set BrioTone to the Neutral preset and let the LUT do the grading.

• "No UVC webcam connected" — replug the camera and click the refresh icon. Built-in MacBook and Continuity (iPhone) cameras are not UVC and won't appear.
• Sliders are disabled — no device detected, or the related Auto toggle is on (turn off Auto to set white balance / exposure / focus manually).
• The image looks different when a call starts — some webcams re-run auto-gain when an app first opens the stream. Re-select your preset once and it sticks. (Manual white balance holds during streaming.)
• macOS blocks the app — it's ad-hoc signed; right-click BrioTone.app → Open the first time.

• UVC provides global color only (no hue/tint/vibrance or per-color LUT on this device).
• Exposed controls and value ranges depend on the camera model.
• Not affiliated with or endorsed by Logitech or Apple. "Logitech", "MX Brio", and "Apple" are trademarks of their respective owners.

• uvc-util by Jeffrey Frey (MIT) — the UVC control engine. See THIRD_PARTY_NOTICES.md.

MIT © 2026 Johan Villalba