IPhone 6s Plus 4K video not playing smoothly on PC
So I have this film project that I am doing for school and I am using my iPhone 6s Plus to record. I am using the Filmic Pro app to record at 4K at 100mbps. when I transfer the files to my PC for playback, the resolution is horrible, not 4K, more like 720p, and it is stuttery. I wasnt even able to play them, but then I installed Quicktime and was able to, but like I said the video resolution and framerate is horrible. I thought maybe it was just QuickTime so I imported the clips to Premiere Pro and exported it. The frame issue seems to be fixed, but the quality is still bad. Does anyone have any tip? Is it a software issue?
iPhone 6s Plus, iOS 9.3.1, None