I can't directly record video in 4K, but I can still make 4K video. My GH3 camera has a resolution of 4608x3456 which is beyond the 4K resolution of 3840x2160. Thus, through creative use of burst mode, which restricts me to time lapse only, I could create a 4K video.
It took a lot of battling with Virtual Dub to get rid of the errors and crashes, but I ultimately found that the "--threads 7 --bframes 0 --ref 5" in the "advanced" settings, without the quotes, gets it to work right. So, here's 709 frames at the full 30,000/1001 (29.97) fps showing the pretty sunset I had.
