4K video on Nexus 5

I've just published a new beta with one exciting early Xmas present for Nexus 5 owners.The app now supports 4K video, yes you can record full 3840x2160 UHD video (only on Nexus 5).I've put a very brief demo video on youtube.It's still experimental but it does work, I'm pretty sure no other app lets you do this.To try it, switch on the camera2 API and opengles 2.0 settings (in the "Other" menu) and two new entries will appear for video quality, 4K and 3.5K.4K is 3840x2160 and 3.5K is 3264x1836.It runs at about 28fps at 4K and 30fps at 3.5K, the default bitrate is 48MBps but you can change this if you want.The sensor on the Nexus 5 is 3264x2448 so it uses the GPU to crop and interpolate to the full 4K size.Pushing all those pixels around is very taxing on the hardware so don't expect the battery to last long while you are filming!I've only just got this to work and it is experimental, it may crash sometimes so please don't rely on it for recording important events.I don't actually have a 4K TV so I haven't seen what the output really looks like at full resolution, let me know.Thanks and Merry Xmas.