VVAS overlay metadata holds the information of geometric shapes and text to be
overlaid on video frames. The vvas_xoverlay plugin parses these structures
and renders the shapes onto the frame. An intermediate plugin
(vvas_xmetaconvert) is required to convert inference metadata from upstream
plugins into overlay metadata before passing it to vvas_xoverlay. Currently
supported overlay shapes are rectangles, text, lines, arrows, circles, polygons,
and masks.
The GStreamer plug-ins set and get overlay metadata from GstBuffer using
the gst_buffer_add_vvas_overlay_meta() API and
gst_buffer_get_vvas_overlay_meta() API, respectively.