LO 5.4.2-3, 1:5.4.2-3~bpo9+1 to be specific, on Debian Linux 9.x stretch. Similarly for Debian 8.x “jessie”. Any attempt to load a video or audio file results in “format of the selected file is not supported”.
Also, I took a presentation created on an older version of LO. It does not play on 5.4.2. So it appears there has been a regression.
You will need youtube-dl or equivalent to copy them to your computer.