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24p to 60i - best conversion method

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bart stevens24p to 60i - best conversion method
by on May 11, 2011 at 4:09:49 pm

I'm trying to convert some of our stock footage from 24p to 60i.
There is lots of information about the reverse 60i to 24p, but I'm struggling to get great results creating the opposite. I know for broadcast they do this for movies all the time, so there must be a better way.
My footage (to my knowledge) was shot on the RED one and 70mm, so it should be a true 24p ( with no pull down or segmented frames).
I've tried numerous methods of adding the 3:2 pull down in my render, but I haven't found a solution that will work for our needs.
My main challenges are:
An increase in stutter (I expect due to the repeating of frames)
Edit pace increases due to higher frame rate.
With a 3:2 pull down, can I maintain audio synch?
I've also tried using pixel motion and Andrew Kramer's frame rate converter, but haven't found the solution that will work yet.
Any information about this is greatly appreciated.
Thanks,
-B


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Dave LaRondeRe: 24p to 60i - best conversion method
by on May 11, 2011 at 4:12:47 pm

I have to ask myself why you'd want to add pulldown to 23.976 progressive footage when most of the time, it will only be removed in order to do a proper job of editing, and which most certainly couldn't be used as-is for any editing involving web distribution.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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bart stevensRe: 24p to 60i - best conversion method
by on May 11, 2011 at 4:45:16 pm

Dave,
The content is already edited, and I'm trying to maintain the timing of the edit.
The content is specifically for a projector demo. The "flicker" associated with 24p won't work for our presentation needs.
So I want to take the 24p stock, convert it to 60i for a 60i presentation.
In that process, I'm trying to maintain the pacing of the original edit and reduce the "stutter" effects of a 3:2 pull down.
I'm still not sure, does the 3:2 pull down maintain the timing of the original 24p content?
If not, how does the broadcast world deal with theatrical films that originated in 24p?


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Dave LaRondeRe: 24p to 60i - best conversion method
by on May 11, 2011 at 5:05:38 pm

[bart stevens] "The content is specifically for a projector demo. The "flicker" associated with 24p won't work for our presentation needs."

The term "flicker" is somewhat nebulous. If by "flicker" you actually mean "low frame rate that doesn't show even moderately fast motion smoothly", adding pulldown isn't going to help. Adding pulldown only spreads the existing motion across more frames every second. No new motion is created; the current motion is simply maintained.

It probably should have been shot at a higher frame rate, but that horse is already out of the barn.

To get smoother motion, you'll need the assistance of frame rate conversion software that will create new intermediate frames using various algorithms based on the motion on the preceding and following frame. The software literally draws new intermediate frames. It works like the process of in-betweening in traditional cel animation.

Two such applications that come to mind are Magic Bullet and ReelVision's Twixtor.

And since we know nothing about the maximum frame rate of the playback device nor the maximum frame rate of the projector, it's tough to give you a straight answer about a proper frame rate.

You should seek the advice of Walter Soyka -- a COW forum leader -- who has great experience in such matters. You'll find him in this forum occasionally, in the main AE forum, and in the Live & Stage Events forum.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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bart stevensRe: 24p to 60i - best conversion method
by on May 11, 2011 at 5:25:26 pm

Dave,
Thanks for the info.
Yes, flicker would be the generic term I was using for the appearance of moderately fast motion in 24p. Personally, I don't mind the look, but the company decision is 60i. The thinking would be the use of interlaced frames would smooth out the 24p "flicker".
I was hoping this would be a task I could do just with After Effects and/or Pixel Motion, but I will look into Magic Bullet and Twixtor.
Maximum frame rate for playback could be 60fps for both the playback and projector, but we would like to show the broadcast standard of 60i.
Thanks again,
Bart


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Dave LaRondeRe: 24p to 60i - best conversion method
by on May 11, 2011 at 5:41:45 pm

[bart stevens] "Maximum frame rate for playback could be 60fps for both the playback and projector, but we would like to show the broadcast standard of 60i."

That's just ONE broadcast standard. Being a broadcaster myself, I can attest to the fact that my station broadcasts in HD at 720p, which is 59.94 (aka 60) FRAMES per second. No interlacing.

At 1080, you run into interlacing.

Personally, if I had the option of playing & projecting at 59.94, I'd take it. I could always convert it to interlaced if I wanted to later.

And understand this: the frame rate conversion software will need to create 2 1/2 times as many brand-new intermediate frames to get from 24 (23.976) to 60 (59.94).

That's a lot of thinking, interpolating and extrapolating. Since frame rate conversion software algorithms work on the TYPE of motion in the shot, you may have to select from several. You may have to use it on individual shots to get the best results. You would want to create test clips to see the results before you dive into the deep end of the pool.

It isn't easy, and it's time-consuming to do a proper job of it. And since this is RED footage, I presume people want a proper job done.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Kevin CampRe: 24p to 60i - best conversion method
by on May 11, 2011 at 4:28:10 pm

I know for broadcast they do this for movies all the time, so there must be a better way.

they use telecine -- just add a standard pulldown in the render settings and render with fields.

but as dave points out, if this is for distribution, most users will then need to remove the pulldown to get it back to 24p to use the footage.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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