Tell me about it. We know we can get 15min out of a Mavic 3 at -40F... but that's just flying circles around us because even we are stupid enough to fly out and do filming at -40F LOL. (but we do at -20F without concern) :) LOL again.
I think that is, perhaps the bit rate? That has everything to do with file size and it's related to how hard the computer has to work in order to render things but Apple (and other?) computers have codecs in hardware to work effortlessly with...
Around these parts (North Pole, Alaska) there's nobody around. Period. Just taking a risk, not putting anyone at risk. Worst case was a walk for a few hundred yards to pick up a broken drone if it landed badly.