This plugin seems to only work during project testing mode, upon distributing/exporting the project, it stops working.
I'm trying to get a 7 second webm file to play.
When I load the distributed version it just boots into a black screen with no warnings and I am unable to skip to the title.
I tried converting the file from webm to mp4, and I still got a black screen and no sucess with getting the splash screen to work but was able to press z and get this warning. If I try loading the mp4, and dont press anything eventually it will boot into the title after the length of the video, despite the video not loading and it just being a black screen 
Viewing post in MV/MZ Pre-Title Splash Videos comments
Nope just a regular, on PC, Windows deployment.
I can get the video to play both in project testing, and in an event but it wont play during the deployed project and only shows up as a black screen. Is this something to do with the issue of the filepaths being broken upon deployment o Windows 10? Deprao, another user was talking about this in the comments earlier
Deprao was talking a couple months ago about how deploying a project on windows 10 will break the filepaths for videos
"Alright, after looking a little more into it, I think I've got some useful information. Because of not managing to get a black screen "debugger" video to run after deploy (turns out video file paths are unreadable after deploy if you include the first slash: "movies/video.webm" works but not "/movies/video.webm", at least on my end [Windows 10]) for a rather embarrassing amount of time, I found a probably fancier solution.
I tried deleting the first slash in the plugin, so it read as "movies/video.webm that didn't work though, do I have to change text in the rpg_core.js or the js script of the plugin itself that I have to edit? He was having the same issue as me I'm pretty sure but he got his splash screen video working on windows 10 after deployment somehow.
But I do believe this is the issue I'm having As I am also on windows 10, and videos will only load as a black screen with no errors. But everything works perfectly in Project testing and on events.