Consider switching (back) to OpenGL-based pipeline
Doing color conversions, copies and flips on the CPU is likely much slower in most cases than using a GPU accelerated one. For cameras with high resolutions and refresh rates it might even be necessary for good performance.
IIRC the reason to stick with non-GL elements was that the gnome/fdo flatpak runtime didn't include the elements in question or the gstreamer version was too old. With Gnome 45 and fdo 23.08 out of the door, this should stop us any more.
Note: it might make sense to use glsinkbin
instead of using the odd glupload ...
dance, see https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/issues/381#note_1978231 and https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/blob/4d9263f93299a359e1d57bfaad261fcd49ac4c84/video/gtk4/examples/gtksink.rs#L30-55