VLC video freezing and grey pixelation

I've used VLC for a long time and it's usually been perfect, but have been having this issue for the past few months. I can't remember if it's since a certain update. It doesn't happen constantly, but it's really annoying. I've seen different advice about the issue posted around such as changing the video output to directX but that hasn't made any difference. Anyone have an idea what causes it and can suggest a proper solution?
Thanks.