Hey Tim,
You can post your form checks together in the same thread in the future.
A couple things to work on here. You're actually going too deep which is why you see your back rounding. Cut off your depth just an inch below parallel.
Also, at the beginning of the squat, send your knees forward as you sit back and bend over. See how your knees track forward during the entire decent? You want to establish your knee position during the first third of the decent and then stop them as you sit back. A tubow could be helpful if you're having a hard time with it.
Cheers.
Tony