Help is on its way.
Before it arrives, please help the help....
What is the source of these videos?
What filetype?
What resolution?
What hardware are you using?
Any network involvement?
How are you trying to make the videos 'work'?
What isn't working?
Any error messages?
If this kind of information is not provided, then when the help arrives, it won't be able to help
Merry Christmas.