30p vs. 60i

[RAM007]

My Canon Vixia HF R200 claims to run at 30p, but saves the recorded video at 60i. What does this mean? Is the camera actually recording 30p and then converting and saving it as 60i for the purpose of making the video more adaptable to broadcast standards? And if so, does that mean that it actually has the 30 full frames per second that Is needed for resolution quality, AND the converted 60 fields per second to give the fluidity of motion as well, which would mean the best of both worlds?

[Skirball]

The I and P stand for interlaced and progressive.  Progressive means that every line in the image gets refreshed in order, 30 times per second.  Interlaced is a technique used to simulate faster frame rates.  Every even line is updated, then every odd.  This allows you to sort of double your frame rate, even though it’s really the same complete frames per second.  I believe standard for television is 60i (actually just short of 60).

[RAM007]

Yes, I am aware of the technichal meaning of the i & p and what they do. What I need to know is, Does the Vixia HF R200 and other cameras like it, which claim to operate in 30p but record in 60i, give the benefits of both!

[Jon]

Well, 60i records alternately the 30"odd"  lines, then the 30 "even" lines, so it's recording 30p (30 lines progressively) and 60i (interlacing the 30 odd then the 30 even lines) both.

[RAM007]

What is the point of that? Does that improve the quality of the picture and the flow of motion? Or is it just a cheap way to get a decsent picture and sell a camera cheap?