Old thread, but I have the same (or worse) problem; I can’t get Impress to play any videos. I’ve installed the k-lite codecs and created the same 12-minute video as an mpg, avi, wmv, ogv and mp4; they all play satisfactorily in Windows Media Player, Media Player Classic and VLC Media Player and in the preview pane of LibreOffice Impress, but I only get the opening frame in a slideshow, and can’t get it to play the movie at all. It doesn’t seem to behave any differently whether linked in the same directory or embedded. I’m using Libre Office 25.8.1.1 in Windows 10 (and have also tried Open Office 4.1.15 on the same PC with results that were even less encouraging). I feel as though this must be a common setup and I’m making a basic error, but at a loss to identify it.