It is a long time since I installed the codec. I don’t remember the options, the original LibreOffice wiki page I linked to says
As a result, LibreOffice typically uses the media framework of each OS for video / audio playback. On GNU/Linux we use GStreamer, on Windows we use DirectShow,
If you can’t see DirectShow, I guess the defaults. You can always change the default player in Start menu > Settings Apps > Default Apps.
Thanks. I appreciate all the help with this.