60GB .mkv playback blocky, convert fail, TV changing scenes, please help

[rotchild]

OK, so I download this (supposedly) 4K movie, 63 GB... First, when I try to play it with VLC, first of all, my 4K TV (Sony) "change scenes": the TV blinks, then it comes back with the image REALLY bright and shiny, looking really weird, don't know how to explain it, sorry... (Sometimes if start a youtube video, it happens too. Sometimes if I close the chrome tab with the video, it comes back to "normal", sometimes it doesn't. It only goes back to normal when I unplug the HDMI cable from the back of the GPU, and plug it back. It's driving me insane.

The other thing is, I still tried to watch the mkv with the "bright". But it plays in hiccups, and the image is all "blocky" and pixelated. I can take screenshots if needed. With mp4 I don't think this happens. I tried converting the mkv to mp4 using VLC itself, but it only outputs a 200 MB's file, containing only the audio (I have available space on the HD before someone asks). Out of ideas.

Can someone please help with these issues? Thank you very much in advance.

[johns0]

When you download a movie you take your chances on if it's good or bad,since it has issues there's nothing you can do to fix it.

[rotchild]

When you download a movie you take your chances on if it's good or bad,since it has issues there's nothing you can do to fix it.

Well, I re-installed VLC and for some reason it played fine later... But I still get issues with the "Scene Select has been changed" message on TV when starting the video, and screen goes all "bright-colored"... Any idea why this happens, and also what is the best tool to convert it too mp4, as VLC has also failed in that regard?