ffmpeg: How can I convert from H.265 into another 10bit format for colour grading? I am very new to dealing with video, so apologies if this is a completely inane question: I was wondering if you could advise me on how to transcode 10bit H.265 All-I 4k footage into some other 10bit format for the purposes of colour grading in Davinci Resolve? I am using the free edition of the software, which does not support H.265. H.265 is also exceedingly tough on my CPU, which I didn't think about when buying a 4k video camera!

I am on Windows. It looks like it would need to be some variant of DNxHR, but I get completely(!) lost trying to construct the terminal commands to make the conversion. 

Here is a very short video in the format that I need to transcode from:

drive.google.com/file/d/1MLaXKDzwaZvbVBp2rlyf7SfxReVbcxID/view 

I'd be really grateful if you could help me out with this!
I'm not familiar with DaVinci Resolve, but if the free version supports 10-bit H.264 you can use HandBrake to transcode to that format with CRF 0 and see if that works.

If that doesn't work you'll need to use FFmpeg. With a bit of fiddling I was able to convert your source file to DNxHR using this command:

ffmpeg -i DSCF1265.MOV -c:v dnxhd -profile:v dnxhr_hqx -color_range 2 -c:a copy DSCF1265.dnxhr_hqx.mov

This also copies the audio over, if you want to exclude it for some reason use -an instead of -c:a copy.

The -color_range 2 bit is important, without it the output looked different from the input (at least when watched with mpv).