What movie file types does Libre Office support?

I know it doesn’t accept FLV, WEBM, or MP4’s.

Please edit your question to provide specific audio / video stream codec detail. FLV / WEBM / MP4 are all container formats that can use a variety of different codecs. Codecs are where support is required. Also indicate your operating system and LO version. Thanks.

Please have a look at:

https://help.libreoffice.org/Common/Movie_and_Sound

Unfortunately, Libre Office does not seem to support its own suggested file types.
Also, answer does not help, for I have Win XP.

Insert > Movie and sound and check the File types drop-down box.