A simple proxy files tutorial video that circumvents use of text editors and editing xml mlt files by using the “help me find missing files” dialog in Shotcut 
Makes editing 4K footage much smoother for me!
2 Likes
Thank you for the hint. I did look at it and can see that in some cases this workaround could be of use.
At the end of the Video the creator explains where this method will not work, which would apply to my editing, as I am planning on using a bunch of pan/zoom, etc filters.
Therefor my original question in regards to the codec remains open.