I'm on mountain lion 10.8.5 and recently my friend gave me a 4K resolution video. When I used QuickTime player, the video is very sharp and some of the text in it can't be seen correctly. However when I used VLC to play it, it played without any errors and I can clearly see the text. I like the UI of QuickTime player, so is there any way to make it appear on QT?
Let's be honest : appart of the UI, Quicktime X a crapy software in term of compatibility. And it became crappier since the development of Perian has stopped. And on Mavericks it's even worse (Perian doesn't work anymore ...). The cause : QuickTime X is based on the AV Foundation Framework which is only powerful with H.264 stuff (yeah the file format sold on iTunes).
VLC is powered by a different video library than QuickTime and it's know to be one of the most compatible player yet.
TLDR: So no there is no there is no solution yet. Let's hope the situation will evolve.
You might want to consider using MPlayerX. It has a very clean interface and works very well, supporting pretty much any format like VLC (and unlike QuickTime, which supports pretty much nothing).