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View Full Version : Help. 30fps to 24fps



ted
04-23-2007, 03:19 PM
I have a client that has a DVD with 30fps video. He wants to try and convert that to 24fps.
Would it be best to capture at 24fps and render a file on a 24fps timeline?
Or would it be best to capture at 30fps and import that to a 24fps timeline?

I'm honestly not sure what the difference would be and told him so. But he's willing to pay for the time to do it.
Any help would be appreciated!

rbartlett
04-23-2007, 05:11 PM
This 30fps video - Is each of the frames truly a progressive frame?

Ted, excuse me if I'm stating the obvious but (for the benefit of others more than anything):
Alternatively it could be 60 fields per second marked incorrectly as 30p.
Either that or it maybe a 24fps that has found it's way onto a DVD after pulldown has been used as a lead-up to it becoming NTSC 60i.

If it is 30p and you want 24p out of it: It really had better have the same production values as would be required to create a good 24p film. If there are panning shots or shots with fast movement, it'll really break down when processed down to 24p. This has to be about the worst conversion request you could have from the list of popular format video types.

Restoring the 24p from a telecine conversion might be possible but this is a job for either an expensive tool or freeware. Not IMHO for one of the usual prosumer NLE, paintbox or compositor culprits.

A cadence change as drastic as 30p to 24p really isn't an easy one to give guidance on.

Please confirm the format and the type of motion in the content. If you've got a talking-head - maybe you can use Aura, Mirage or AE. If you think your client could stand blended frames, Vegas or maybe SE 1.1.....

If you are really, really lucky the DVD will have an I-Frame incidence 24fps with B and P frames swelling the resolvable frames up to 30fps. However the cadence of the I-Frames may be such that you'd not want to throw the rest away.

In this situation, I'd be:

1. Worried about the DVD bit. If this is already DVD-Video, you might have issues pulling out the quality that you need.

2. Questioning the wisdom of a 24p conversion if the original is truly 30p. Is it the filmic look they want? If so, there may be other options where the faster cadence may turn out to be useful to maintain rather than destroy.

3. Recommending another attempt from scratch in 24p or 25p. (assumes the work can be repeated without too much trouble or strife)

4. Set the customer expectations that this might turn out to be a compromise that isn't worth pursuing.

ted
04-23-2007, 06:59 PM
I should have known you'd come to my rescue! :D
Everything you said confirmed my results attempting this.
I was using VT to capture. I even changed VT's capture rate to 29.97, 24fps & 23.95?
Brought all to SE on 24fps timeline & 30fps timeline.
Rendered out to 24fps, 32.95?
All resulted in softer images and often added strobbing highlights.

While I don't think he needs it, I'm curious about the process because I'm sure we'll be needing similar processes since there are even more "standards" in our future.

I've tried to discourage this guy a few ways but he thinks he needs it. It's a 2 hour Video DVD. They shot 1/2 of the video on one camera at 24fps and the other 1/2 on a different camera at 30fps.

Has anyone had much experience changing frameates cause I don't have a clue?
Thanks, especially Richard.

mgrusin
04-23-2007, 07:58 PM
I've used Aura in the past to convert between frame rates, it seemed to do a decent job especially if the source is already interlaced (then it can do field-based pullups, if I have the terminology right).

-MG.

John Perkins
04-24-2007, 07:39 PM
This will probably be harder because of the camera mixing.

One of the two cameras footage has already been pulled up or down, probably the 24p one, to the framerate they settled on for the DVD.

It may be that you have use two different tactics for the two different cameras.

I would take a cue from a DVD ripping, I mean, DVD backup site. They have good tutorials on mixed footage DVD's, since many commercial DVD's mix film and video footage. Try www.doom9.net.

Just instead of outputting to MPEG4 like they suggest, use NT25, SpeedHQ, DV or something else that is better for editing.

ted
04-24-2007, 10:27 PM
Great info guys thanks.
As it turns out the DVD they supplied didn't have audio, (by their mistake), :eek: and after telling them that they could do this themselves with Premiere Pro, they didn't think it was needed after all??? :D

Funny thing is, they still offered to pay a couple hours at full rate??? I felt too bad for them to take their money.
Still a conviluded world with all the file converting we're headed for!

rbartlett
04-25-2007, 01:00 AM
Yeah, assuming your problem is singular and not a double-trouble like the one you offered up - there are more than 800 alternative combinations for src->dst conversion now. That is just assuming that the src is in a well known and designated video standard format in the first place.

At least you knew what the two clips properties were!