so, I am editing 2400x1350 raw clips. My timeline is set at 1080p resolution with proxies even smaller in size (I have a slow computer). I realize now setting the timeline to 1080p was a mistake. My timeline has 1080p and 2400 clips mixed in, but it made everything 1080p (unless I toggle the proxies on, then it is even smaller file size wise). So I think the timeline got auto set when I imported the first clip which was 1080p. The bulk of my edited footage is 2400 though. Now, I'm trying to export in the largest resolution so that I can color the raw clips in davinci resolve but it won't let me change out of 1080p. And if I do the black box of death appears. I've tried set file to frame size and all that but if I change the sequence settings the black box of death stays and nothing adjusts.
How can I export the timeline, even the one 1080p clip, in 2400x1350 so I get maximum quality to color the footage? Mind you, this is a 1.5 hour feature so starting from scratch is far from an option (hopefully).