Subtitle Edit plugin for Logi Options+

Control Subtitle Edit from a Logitech device: MX Master (Actions Ring), MX Keys, or the MX Creative Console (buttons and dials).

Built on the Logi Actions SDK. Runs on macOS and Windows from the same source, and is tested on both.

Submitted to the Logi Marketplace and awaiting review. Until it is approved there, install from a release with the steps below.

Screenshots

The Actions Ring with the plugin's actions, each with its own icon, and the grouped action list in Options+:

How it works

Subtitle Edit has no automation API, so the plugin drives it the way the SDK recommends: by simulating the keyboard shortcuts Subtitle Edit already listens for.

The important detail is where those shortcuts come from. Subtitle Edit registers its actions by name and stores the key bindings in the user's own Settings.json. The keys are therefore whatever that user configured, and the primary modifier differs by platform (Win, meaning Command, on macOS; Ctrl on Windows). Hard coding a key combination would break for anyone who remapped a shortcut, and break again across platforms.

So the plugin reads Settings.json at load, resolves each action to its real keys, and builds one plugin action per shortcut. Remap something in Subtitle Edit and the plugin follows. An action with no keys assigned never appears, because there is nothing to send.

Actions go to the focused application, so Subtitle Edit must be in front. The plugin is linked to Subtitle Edit (bundle dk.nikse.subtitleedit, process SubtitleEdit), so Options+ activates it automatically when Subtitle Edit comes forward.

Where the settings are read from

1. SUBTITLE_EDIT_SETTINGS, if set.
2. Next to a running SubtitleEdit executable. Subtitle Edit treats itself as portable when it is not installed under Program Files and then keeps Settings.json beside its executable, which is how the Windows zip is normally run.
3. %APPDATA%\Subtitle Edit\Settings.json on Windows, ~/Library/Application Support/Subtitle Edit/Settings.json on macOS.

This reads Subtitle Edit 5's Settings.json. The classic Subtitle Edit 4 keeps its shortcuts in Settings.xml, in an unrelated format, and is not supported.

Actions

Buttons are grouped as Playback, Timing, Lines, Text, File, Edit, Find and Tools. Anything bound in Subtitle Edit but not named in SeCatalog.cs still appears, under its Subtitle Edit control group, with a name derived from the action name.

Dials (MX Creative Console):

Dial	Turn	Press
Subtitle line	Previous / next line	Focus selected line
Video position	Back / forward 500 ms	Play or pause
Waveform zoom	Zoom out / in	none
Next error	Previous / next error	List errors

Reload shortcuts re-reads Settings.json after you change a shortcut in Subtitle Edit. New actions appear after the plugin itself reloads, since the action list is built at load.

Building

Requires the .NET SDK and Logi Options+ (the build references PluginApi.dll from the installed plugin service).

cd SubtitleEditPlugin
dotnet build                      # builds only
dotnet build -t:InstallPlugin     # also links it into the plugin service for testing
dotnet build -t:UninstallPlugin   # removes the link

After InstallPlugin, restart Logi Options+. A plain dotnet build never touches the plugin service.

Installing and running locally

Once the Marketplace listing is approved, installing is a double click on the .lplug4, which opens Logi Options+ and walks you through it. Until then, or for a package you built yourself, install it manually.

From a build, with the .NET SDK (macOS or Windows):

cd SubtitleEditPlugin
dotnet build -c Release -t:InstallPlugin

This builds the plugin and links it into the plugin service. Restart Logi Options+, launch Subtitle Edit, and the Subtitle Edit actions appear in Options+.

From a released package, without the .NET SDK (Windows): the .lplug4 is a tar, so unpack it into a folder and point the plugin service at that folder with a .link file.

$pkg  = "$env:USERPROFILE\SubtitleEditPlugin"
$dest = "$env:LOCALAPPDATA\Logi\LogiPluginService\Plugins"
New-Item -ItemType Directory -Force -Path $pkg, $dest | Out-Null
tar -xf "$env:USERPROFILE\Downloads\SubtitleEdit_1_3.lplug4" -C $pkg
Set-Content "$dest\SubtitleEditPlugin.link" "$pkg\" -NoNewline -Encoding ASCII
Stop-Process -Name LogiPluginService -Force

The plugin service restarts on its own. Launch Subtitle Edit, open Options+, and the actions and the default Actions Ring layout are there.

If the action panel is empty, the plugin did not load. Check its own log at %LOCALAPPDATA%\Logi\LogiPluginService\Logs\plugin_logs\SubtitleEdit.log: no log file, or one without a version line, means the .link is missing or points at the wrong folder. Recreate the .link and restart the service.

To remove a manual install, delete the .link file and restart the service, or run dotnet build -t:UninstallPlugin if you installed from a build.

Action symbols

Each action has its own icon in the Options+ picker. They are SVGs in SubtitleEditPlugin/package/actionsymbols/, named after the action's full class name, with the parameter name after a three underscore separator. Regenerate with:

python3 scripts/gen-action-symbols.py

The class is called SeCommand rather than something more descriptive because a tar entry name cannot exceed 100 characters, and the longest Subtitle Edit action name would otherwise push its symbol file past that.

Languages

Action names are shown in the language of the Logitech software, in all 26 languages Subtitle Edit ships. The translations are not written by hand: Subtitle Edit already translates every one of these command names, and ShortcutsMain.BuildCommandTranslations() says which language string belongs to which action, so they are lifted from there.

open "loupedeck://plugin/SubtitleEdit/xliff"     # service writes the neutral xliff
python3 scripts/gen-localization.py              # fills targets from Subtitle Edit

Group names, dial names and descriptions have no Subtitle Edit equivalent and stay in English. Dutch resolves only 29 of 78 names because Subtitle Edit's own Dutch translation is itself incomplete.

Default profile

The package ships a default Actions Ring layout in profiles/DefaultProfile72.lp5 (device 72 is the Actions Ring). The plugin service uses it as the template when a user first sets up the Subtitle Edit profile, so a fresh install starts with actions in place rather than empty slots. It is a profile exported from Options+, not hand built, and applies only to new profiles, never overwriting an existing one.

Packaging

Two package formats, same contents, different consumers:

• python3 scripts/pack-lplug4.py writes the tar .lplug4 for direct install (the local plugin service rejects a zip silently).
• python3 scripts/pack-lplug4-zip.py writes the zip SubtitleEdit_<v>_marketplace.lplug4 for the Logi Marketplace upload (its validator unzips the file; a tar fails there).

The Marketplace re-serves a tar to end users, so only the tar reaches an installed device.

Original packaging notes

cd SubtitleEditPlugin && dotnet build -c Release
python3 ../scripts/pack-lplug4.py

A .lplug4 is an uncompressed POSIX ustar archive with bin/ and metadata/ at its root. The SDK documentation calls it "essentially a zip file"; it is not. A zip is rejected silently, so double clicking it appears to do nothing. Verified by unpacking a published Logitech plugin.

Status

• Tested on Windows and macOS. Installed in Logi Options+ on both, the actions drive Subtitle Edit 5 through the Actions Ring, each action shows its own icon, the grouped action list appears as expected, and the default Actions Ring profile loads on a fresh install.
• The shortcut reader and key translation are also covered by tests against a real Settings.json: all 80 entries resolve, the 2 that are dropped are the ones Subtitle Edit leaves unassigned, and the modifier and key values are asserted for the tricky cases (number row D4, arrows, numpad Add and Subtract, Back, and multi modifier combinations such as Win+Alt+Shift+D).
• Compiles against the shipped PluginApi.dll.
• Submitted to the Logi Marketplace and awaiting review.