The HDX is a duel format camera. It can record either 720p or 1080i. When you shoot 1080l, you are laying down 1080 60i to tape. When you shoot 720p, you are laying down 720 60p to tape. When you shoot 24p in 1080, a pulldown is added to get you to 29.97.
You can only use the FRC with 720p footage, and your choices are limited with the HDX.
Chris Bell
PS: anyone know if you can frame rate convert 60p footage from the HDX with the FRC for slow mo effect? Is 60p flagged like a varicam?