Volume11

Per-application volume for Windows 11, from the notification area.

Windows forgets. Volume11 stores a level per program and sets it again when that program starts playing.

Features

• Levels stored per executable, kept across restarts and updates
• Applied automatically when a program starts playing
• Switch the output device from the window; each device keeps its own levels
• Follows the default output device when it is changed elsewhere
• Event driven, no polling
• Application icons read from the executables
• True-black theme, seven accents
• Autostart, switchable from Task Manager
• Closing the window keeps it running in the tray
• One instance at a time

Install

Download Volume11-Setup.exe from the latest release and run it.

Installs per user under %LOCALAPPDATA%\Programs\Volume11, no administrator rights. Running the setup elevated installs to Program Files instead. A new release installs over an older one and keeps its settings. Uninstall through Windows Settings removes the program, shortcuts and autostart entry; it asks before deleting saved volumes.

Volume11.exe is attached to the release as well, for a portable copy.

The build is not code-signed, so SmartScreen warns once.

Using it

Action	How
Open or close	Left-click the tray icon
Menu	Right-click the tray icon
Switch output device	Click the device name
Save current levels	Save button
Apply saved levels	Apply button
Move the window	Drag the empty part of the header
Keep it on top	Pin button
Hide	Esc, ✕, or Alt+F4
Quit	Tray menu → Quit

Closing only hides. The window opens at the bottom right of the primary monitor, above the taskbar, whatever its resolution or scaling. Dragging moves it for now; the next open puts it back.

Flags:

• --show opens the mixer immediately
• VOLUME11_CONFIG=<path> for a portable configuration file

Configuration

%APPDATA%\Volume11\config.json:

{
  "version": 2,
  "settings": {
    "auto_apply": true,
    "unknown_app_policy": "leave_alone",
    "default_volume": 50,
    "always_on_top": false,
    "start_with_windows": false,
    "accent": "#9AA3AD",
    "oled_black": true
  },
  "devices": {
    "{0.0.0.00000000}.{2e3dc39e-…}": {
      "label": "Headset Earphone",
      "apps": {
        "spotify.exe": { "volume": 45, "muted": false, "label": "Spotify" }
      }
    }
  }
}

Levels are kept per playback device, keyed by its endpoint id. Windows itself stores per-program volume per device, so one level per program across all devices would fight it on every switch. A version 1 file is migrated on the first start: its levels move to the device in use.

unknown_app_policy: leave_alone or apply_default.

Autostart lives in the registry, not here, so Task Manager and Volume11 agree on it. Switching it off marks the entry disabled instead of deleting it, which is why it stays listed under Startup. If the entry points at a copy that has been deleted, the next start repoints it.

Written atomically. An unreadable file is moved to config.json.broken.

Offline

Volume11 makes no network connections: no networking dependency, no network code, and the binary imports no networking library. To check:

cargo tree | grep -iE "reqwest|hyper|ureq|curl|tokio|rustls|openssl"   # no matches

dumpbin /dependents Volume11.exe    # no ws2_32, winhttp, wininet or urlmon

The https:// strings in the binary are panic and documentation text from egui and wgpu; there is no HTTP client to fetch them. The libraries loaded at run time are Windows' own graphics and shell components (d3d12.dll, dxgi.dll, d3dcompiler_47.dll, shcore.dll).

Building

cargo build --release
cargo test
cargo run --example smoke        # prints live devices and audio sessions
python tools/make-icon.py        # regenerates assets/icon.ico

The installer needs Inno Setup:

ISCC.exe /DAppVersion=0.2.0 installer/volume11.iss

Releases are built with MSVC; the GNU toolchain works too.

How it works

Module	Responsibility
src/audio/engine.rs	Owns the COM objects on one thread, caches sessions by process id
src/audio/callbacks.rs	WASAPI callbacks, push into a channel and return
src/audio/process.rs	Process id to executable name and label
src/audio/policy.rs	Setting the default device through IPolicyConfig
src/config.rs	JSON, atomic writes
src/tray.rs	Tray icon and menu, own Win32 message loop
src/instance.rs	Single instance, and the installer's quit request
src/autostart.rs	Run key plus Task Manager status byte
src/ui/	Window, theme, slider, icons
src/ui/placement.rs	Primary monitor work area and taskbar geometry

The UI thread never touches COM. It sends commands and receives events over channels. egui runs reactively, so an idle Volume11 draws nothing.

Windows has no public API for changing the default playback device. The Sound settings, EarTrumpet and SoundSwitch all use IPolicyConfig, an undocumented COM interface unchanged since Windows 7; Volume11 does the same and sets the device for all three roles, as the quick settings flyout does.

Rendering goes through wgpu on Direct3D 12. Windows ships no OpenGL past 1.1; everything above comes from the GPU driver, so a machine on the Basic Display Adapter has none. D3D12 is a Windows API with a software fallback and better maintained drivers.

History

A rewrite. The original was .NET 9 WPF with NAudio and EF Core/SQLite: 201 MB plus six DLLs, and a one-minute timer that re-enumerated every audio session.

License

MIT, see LICENSE.

Parts of this project were created with AI assistance.