Good afternoon,
I’ve got a problem in my UE4.12 game.
I’m trying to put a video as a background in my menu interface.
Si I created a Media Texture out of a Media Player, and a Material with my Media Texture.
Then in my widget I added in an “image” canvas my material. In the editor preview the video works, but not in game. There is a black canvas instead of my beautiful video. I’m sad.
So please if somewone knows what can my problem be, I thank him for letting me know.
Thank you 
.
Media Player functionality was horribly broken in 4.12, can you consider upgrading to a newer engine version? The media player was overhauled in I think 4.13.
If youre stuck with 4.12, make sure your media file in Windows is in your project directory under /Content/Movies. (If there is no Movies folder create one and put it in there)
Then in Unreal click your Media Source and click the small ‘…’ button then change the path to the /Content/Movies path of your file
This works about 50% of the time in my experience, its to do with the Packaged Game not knowing where to look for the media file, this changes it to a local path.
If this doesnt work Id reccomend upgrading engine version