When the pattern being rendered by videotestsrc doesn't have motion, cache a rendered buffer and output it repeatedly with updated metadata. Based on a patch by Edward Hervey <edward@centricular.com> Fixes https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/issues/10 Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1293>