I'm not an expert on Xeons, but I think you can get the same performance for the same or less money from i7s, and the motherboards should cost less. If you're mainly going to be recording video, a quad-core should be fine, but if you're going to be re-encoding it, with something like Handbrake, then a hyper-threaded quad-core (eight logical cores) is the way to go. So either an i5-4430 (4C/4T, $189), or an i7-4770 (4C/8T, $300).
Then put a lot of money into a good video card, such as nVidia GTX 760 ($250), a GTX 770 ($340), or a Radeon R9 290 ($480). According to Tom's Video Charts,
http://www.tomshardware.com/charts/2014-vga-charts/16-Battlefield-4-1080p,3608.html
Battlefield 4 at 1080p will get 48.6 fps with a GTX 760, a GTX 770 will get 66 fps, and an R9 290 will get 74 fps.
Regarding the CPUs, you might want to ask your question in the CPU or motherboard forum for a better answer.