Threek

Because it's funny.

A macOS menu bar app that intercepts the ⏯ key and lets you choose which app receives the command when several apps are registered with Now Playing at the same time — playing or paused.

Download · threek.lost.plus · macOS 15+, Apple silicon and Intel

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What it does

macOS hands play/pause to whichever app most recently claimed the Now Playing session. With Spotify, Music, and a browser tab all paused at once, pressing ⏯ is a lottery. Threek intercepts the key, enumerates every app in the Now Playing registry, and pops up a HUD so you pick the target. Apps are listed alphabetically, so each one keeps its F-key from one press to the next.

# of apps	Behavior
0	Re-injects the key so the system handles it normally.
1	Sends the key directly to that app and briefly shows it over the key you pressed.
2	HUD shows two icons. ⏮ sends left, ⏭ sends right.
3	HUD shows three icons. ⏮ / ⏯ / ⏭ map to the three apps.
4+	HUD shows a scrollable row. ⏮/⏭ move a selection ring, ⏯ confirms.

If exactly one app is actually playing, any media key goes straight to it; the HUD just flashes that app over the key, no picking needed. ⏮/⏭ follow the same routing as ⏯. Threek reads the real F7–F9 media keys, so no Karabiner remapping is needed.

To show only app icons, turn off Show Album Artwork in the menu bar menu.

With several displays, the HUD appears on the one the cursor is on; on the built-in display it lines up with the F7–F9 keys.

Hold ⏯ for half a second to pause everything that's playing; the HUD shows each app it paused. A normal tap still acts on release, so it works as before.

QuickTime Player gets one entry per open video or audio file, with the file's own frame or cover art, so each one can be paused on its own. QuickTime has no tracks, so ⏮/⏭ do nothing for it.

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How it works (macOS 15.4+)

Since macOS 15.4, the mediaremoted daemon refuses to hand Now Playing data to third-party processes — MRMediaRemoteGetNowPlayingClient(s) returns empty from any unsigned context. This is why the original implementation broke.

Threek v2 works around the entitlement wall using the bundled MediaRemote Adapter (vendored in Vendor/): it spawns /usr/bin/perl — a system binary that is entitled — and loads a small helper framework that talks to MediaRemote and reports back as JSON.

On top of the stock adapter, Threek adds a clients command (Vendor/mediaremote-adapter/src/adapter/clients.m) that enumerates all registered Now Playing apps, including paused ones — the data the stock single-active-app get/stream commands can't provide.

Concern	Mechanism
Discovery (which apps, incl. paused)	mediaremote-adapter.pl … clients inside the perl shim
Identity	bundleID, displayName, PID, parent bundleID (collapses WebKit/browser helpers)
Send play/pause	AppleScript (osascript) to the picked app; falls back to the adapter's MRMediaRemoteSendCommand (current now-playing app) when AppleScript isn't possible

The framework is built from source by scripts/build-adapter.sh (a Xcode pre-build phase) — no committed binaries.

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Install

1. Open Threek.dmg and drag Threek into Applications.
2. Open Threek. macOS refuses the first launch because the app isn't notarized by Apple: go to System Settings → Privacy & Security, scroll down, click Open Anyway, and open it again.
3. A short welcome walks you through allowing Threek under Privacy & Security → Accessibility, so it can see the media keys.
4. The first time Threek controls a media app, macOS asks for Automation access to it. Allow it once per app.

Threek updates itself through Sparkle. The menu bar icon has Enabled, Open at Login, Check for Updates and About. The UI is in English and 28 other languages.

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Build from source

Prerequisites: Xcode 26+ (the PermissionFlow package needs swift-tools-version 6.2), XcodeGen, CMake

git clone https://github.com/LPFchan/Threek.git
cd Threek
brew install xcodegen cmake   # if needed
xcodegen generate
open Threek.xcodeproj

Set your Development Team in project.yml (or Xcode → Signing & Capabilities), then ⌘R. The adapter framework builds automatically as a pre-build phase. Debug builds add a Preview HUD menu item (⌘P) for checking the picker.

sh scripts/build-app.sh builds the release app into build/Threek.app (universal, version from the latest v* tag, build number = commit count) and sh scripts/make-dmg.sh packs it into build/Threek.dmg with DMGMaker and the background from Packaging/dmg-background.html (re-render it with scripts/make-dmg-background.sh). swift scripts/make-icon.swift redraws the app icon.

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Releasing

Push a version tag: git tag v1.0.0 && git push origin v1.0.0. .github/workflows/release.yml then builds and signs the app, packs the DMG, publishes a GitHub release, and adds it to docs/appcast.xml, the Sparkle update feed. GitHub Pages serves docs/ at threek.lost.plus (a DNS-only Cloudflare CNAME to lpfchan.github.io), which is also the homepage.

It needs three repository secrets:

• SPARKLE_PRIVATE_KEY: signs updates; the app only installs updates signed with it. Its public half is SUPublicEDKey in project.yml.
• SIGNING_CERT_P12, SIGNING_CERT_PASSWORD: the "Threek Self-Signed" code-signing certificate (base64 .p12). Gatekeeper doesn't trust it, but keeping the same one means macOS remembers the Accessibility grant across updates.

GitHub can't show secrets again; backups live in passage (folder sparkle) and in the maintainer's login keychain (Sparkle account threek). Losing the Sparkle key means existing installs can never update again.

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Project structure

Threek/
├── project.yml                 # XcodeGen — no .pbxproj committed
├── scripts/
│   ├── build-adapter.sh        # Builds MediaRemoteAdapter.framework from source
│   ├── build-app.sh            # Release build + signing → build/Threek.app
│   ├── make-dmg.sh             # build/Threek.dmg via DMGMaker
│   ├── appcast.py              # Adds a release to docs/appcast.xml
│   └── make-icon.swift         # Draws the app icon
├── Packaging/                  # DMG background + DMGMaker patch
├── docs/                       # threek.lost.plus: homepage + Sparkle feed
├── Vendor/
│   └── mediaremote-adapter/    # Vendored adapter (BSD-3) + our `clients` command
├── App/
│   ├── ThreekApp.swift         # @main
│   └── AppDelegate.swift       # Event tap lifecycle, menu bar, routing
├── MediaKeys/
│   ├── MediaKeyInterceptor.swift
│   └── MediaKeyEvent.swift
├── NowPlaying/
│   ├── NowPlayingService.swift # Perl-shim discovery + AppleScript dispatch
│   └── NowPlayingApp.swift     # Model
├── Popup/
│   ├── PopupController.swift   # NSPanel + SwiftUI HUD
│   └── SelectorViewModel.swift # State machine
├── Preferences/
│   └── LaunchAtLogin.swift
└── Resources/                  # App icon, Localizable + InfoPlist string catalogs

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Privacy

• No analytics. No telemetry. The only network request is Sparkle's update check against threek.lost.plus/appcast.xml.
• Now Playing metadata stays in-process.
• Accessibility is used only to intercept hardware media-key events.

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Known limitations

• Only apps that register with macOS Now Playing are discoverable.
• The adapter relies on a private-API workaround Apple could close in a future macOS release. mediaremote-adapter.pl … test detects this at runtime.

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Credits

• mediaremote-adapter by Jonas van den Berg (BSD 3-Clause) — the entitlement workaround that makes v2 possible. License in Vendor/mediaremote-adapter/LICENSE.

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License

MIT — see LICENSE.