Frame Rates (30p vs 60i)

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bradywurtz

Active member
This is a very noob question, seeing as i've been doing stuff for a while now. but i'm completely confused on the difference between 30p and 60i frame rates. I understand that 30p is 30 frames per second, and 60i means 60 frames interlaced, but also means it's only 30 frames, just interlaced with each other.

so what is the benefit of using 60i over 30p? does it have to do with your delivery (tv, web, dvd), or does it have to do with something else?

please help explain this to me! thanks!
 
60i samples motion 60 times per second. Forget about it being only 30 frames. 30p will have much more "judder" when anything moves.

For web, stay away from 60i, computers can't properly display it. For TV or DVD, 60i works fine, but using it over 30p will depend on what you're shooting.
 
Here's the easiest way to think about it:

1080/30p = 30 frames at 1920x1080
1080/60i = 60 frames at 1920x540

Forget fields and interlacing and all that confusion, and just get down to what the actual facts are -- in interlaced you get twice as many frames, at half the resolution. More motion samples, less resolution. In 30p you get half as many frames, but twice the resolution.

60i = "live", "looking thru a window". It's still common now, but will certainly be eventually done away with in the next major revision to television standards, where it will be replaced by 1080/60P.
 
bradywurtz said:
This is a very noob question, seeing as i've been doing stuff for a while now. but i'm completely confused on the difference between 30p and 60i frame rates. I understand that 30p is 30 frames per second, and 60i means 60 frames interlaced, but also means it's only 30 frames, just interlaced with each other.

so what is the benefit of using 60i over 30p? does it have to do with your delivery (tv, web, dvd), or does it have to do with something else?

please help explain this to me! thanks!
Click to expand...

I really don't like to do this, but this question is answered in depth with examples in my 24p & Frame Rates tutorial, and it's one of the main reasons I made it in the first place. It's totally on point.
 
Ok, so basically there's no reason (for me at least) to ever shoot anything in 60i unless someone says 'well i'm shooting it in 60i so i need you to do it too so they match' or 'this switcher we're using only works in 60i'. If i was ever to go out for shooting a documentary, a short narrative film, or any other freelance filming, there's no time when i would ever find the benefit of shooting anything in interlace.

I understand the difference in look and style and other technical issues that come with shooting in 24fps or 30fps or even 60fps. but that's with shooting them all in progressive. I don't think i'd ever find a benefit for choosing, on my own, to decide to shoot anything in interlace.

thanks everyone! think i got the insight i needed on this one!
 
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