I actually tried it just now, as I just got a new 6D. The one we were shooting with this summer didn't capture sound, that might be why it was able to do it. Right now, the math doesn't add up. I've tried 1728x768 with 2.20:1, and I got about 15 seconds before it started skipping, using a Sandisk 32GB Extreme card, so yeah, you might be right.
I'm also unsure of the version that camera was running. It wasn't able to capture sound at the time, so it might have been one of the builds before that, or the module wasn't loaded.
I'm also unsure of the version that camera was running. It wasn't able to capture sound at the time, so it might have been one of the builds before that, or the module wasn't loaded.