window:// URI scheme for capturing individual windows

[joaormatos]

I stumbled upon a mysterious, undocumented URI scheme while exploring the Playlist window in the VLC GUI.

Such URIs are found under the Playlist window, specifically: Devices/Screen capture/Applications

By choosing "Information..." in the context menu, I can find URIs such as window://0x2e00011 which allow me to select desktop windows as video sources.
Example image:


I can then use such URIs through the command line interface together with options for the screen:// URI scheme, such as --screen-fps

Is there any documentation about this that I missed, excluding the source code?

It's a very interesting feature that could be really useful for rich program documentation, bug reporting and screencasting.

Also, I couldn't find any way to use these URIs in the GUI other than the options available in the context menu.


VLC version: 2.0.3 Twoflower (revision 2.0.2-93-g77aa89e), obtained from the official Debian GNU/Linux 7.3 "Wheezy" repository, amd64 arch.
Desktop environment: GNOME 3 Fallback, with compositing enabled in metacity's dconf configuration. I assume this wouldn't be possible without a compositing WM.

[Rémi Denis-Courmont]

It's just window:// followed by the X11 window ID. VLC enables compositing automatically during capture.