Does anyone know what exactly this is? I'm hoping it's the progressive alternative to interlaced NTSC? I had to rip some material off a DVD and then deinterlaced it, and was then hoping to drop it into a progressive timeline (I'm going to be using a lot of motion and compositing) .  The project properties I'm using is 720x480 NTSC with the 29.97p...will this give me a progressive output movie? Oh, if you've never seen this, it's when you are creating a custom project property, and when selecting 720x480, you can select either 29.97i or 29.97p

i is interlaced. p is progressive. If your media is deinterlaced, use p.