Audio plays but no video on iPad

[sonny3568]

Hi, I have an iPad Mini 2 and VLC 2.7.8
My iPad recently stopped showing the video for the mkv files that I'm trying to play on it, but weirdly the audio still plays fine.
I have edited the file names such that there are no spaces, a tip that I picked up from a previous forum, and deleted and re-installed the app, but it's had no effect.
The app has thumbnails depicting scenes from each of the video files, so I think it is reading them, it's just not playing the video. Kind of frustrating.
Would be happy to provide any other information if needed and would appreciate any help on this!

Thanks.