If you have been suffering with video stuttering during playback in Quicktime and Final Cut even after creating optimised media and having a Mac fast enough to cope with other 4K footage, then I may have a solution for you. There seems to be some problem in the way that Apple video playback is handling the Typhoon H codec, so even if you transcode (using an apple product) to optimised media you still end up with the stuttering. I remembered some people used to have this problem with the GoPro codec so googled the solution to that. I used a free app called Mpeg stream clip Squared 5 - MPEG Streamclip video converter for Mac OS X to convert my 4k 30fps footage to Apple ProRes 422 and while the files are HUGE the stuttering seems in the most part to disappear. Hope this helps someone.