gstreamer/tests/examples/gl/gtk

--- Description of the GTK examples ---

- gtkvideooverlay:
Show how to use the videooverlay interface through GTK.
It's possible to switch bettween GST_STATE through four buttons.

-filternovideooverlay:
A more complex pipeline is switched bettween the GST states
without using the videooverlay interface.

-filtervideooverlay:
A more complex pipeline is switched bettween the GST states.
using the videooverlay interface.

-fxtest:
switch bettween effects of the gleffects filter.

-pixbufdrop:
drag and drop a png file and overlay it using alpha channel.
It uses gloverlay filter.

-switchvideooverlay:
change the videooverlay window while the stream is playing.

--- How to build the GTK examples ---

Using autotools or Meson.