why impress doesn't accept mp4 video?

impress on Libreoffice 6.0.3.3. When I want to insert a short mp4 video clip, it says that the format is not accepted.
Is there an extension I have to use? If yes, which one?

This is a duplicate question.problem inserting video in impress

Please provide

  • what operating system you are using
  • codecs used in the MP4 file