When clicking on a video file of any type, it brings my computer to a crawl. Mouse movements get choppy, any other programs hang temporarily, and video takes several seconds to preview. Doesn't matter if local or on SAN. Pictures preview properly.
Using 13.11.3 currently.
Check the appropriate codecs are installed and up to date:
Opus itself contains no video playback code; it's all down to the system's codecs.