DownloadHelper CoApp is a multi-platform (Windows, Mac, Linux) application providing the Video DownloadHelper browser add-on with a set of extra features not available directly from the add-on:

• file writing API
• launching default video player application on a data file
• a build of the ffmpeg video converter

DownloadHelper CoApp complies with the native messaging protocol and is not intended to be used directly from the command line.

Installer executables for the various platforms are available from the releases page.

Windows: download the .exe file, double click on it, and follow the instructions.

Mac: download the .pkg file, double click on it, and follow the instructions.

Linux debian-based: download the .deb file and install it: sudo dpkg -i <deb file>.

Linux other: download the .tar.bz2 file, unpack and move to a desired location, and run ./vdhcoapp install.

At this point, the app should be recognised within your browser.

You can check in the Video DownloadHelper add-on settings:

Mac DMG: download the .dmg file, open it and move the app to Application folder. Launch the app once to register its manifest within the different browsers (it will show a notification then close). Re-run the app if you ever move the application to a new location.

Linux tar.bz2: download the .tar.bz2 file, extract it where ever you want to install the app, then run <install location>/vdhcoapp install to register the manifest within the different browsers. Re-run the install command if you ever move the application to a new location.

See out troubleshooting section here.

After the app is installed, the coapp installs a json file into browser-specific directories, as described by the Mozilla, Google and Microsoft documentation:

• https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Native_manifests
• https://developer.chrome.com/docs/extensions/mv3/nativeMessaging/#native-messaging-host-location
• https://learn.microsoft.com/en-us/microsoft-edge/extensions-chromium/developer-guide/native-messaging?tabs=v3%2Cwindows

You can see the list of files installed by running vdhcoapp install. Those files can be remove with vdhcoapp uninstall.