importing 25fps to 30fps timeline

chromeboy007

chromeboy007

Well-known member
Hey peeps,

A client of mine wants to integrate some 25fps stock foots into video that I have shot for him at 30fps, thus on a 30p timeline. I have done it with 25fps animation before, but I wonder if it will work with actual video footage shot on PAL. I can't shoot PAL 25fps myself as my cam is NTSC, I don't want have to buy some 25fps stock foots off istock just to test it. If you have done it before and know that it works or doesn't work, please let me know.

Thanks

CS4 Premiere, HPX170
 
The issues between NTSC and PAL are two fold. First is frame rate, second is resolution.

If you're working in NTSC, I recommend staying there.
 
25p and 30p don't mix well. That's just math. There's no common frame rate which suits them both (like 30 fps and 24 fps can sit well within 60 fps), and they don't convert well to one another (too little of a difference).
 
I have dumped 25fps animation onto a 30 fps timeline before. Render. Looks fine. Are video footage different?
 
chromeboy007 said:
I have dumped 25fps animation onto a 30 fps timeline before. Render. Looks fine. Are video footage different?
Click to expand...

There will probably be stuttering if everything is playing at 30p

Look more closely, step through the frames and you will see either blended frames (if you have frame blend on), or duplicate frames
 
Yep, most likely. There's just not enough of a difference for clean interpolation.

If there's very little motion, you might be able to get away with it, but you're very likely going to see some stutter and some ghosting.
 
Three options:

1.) Drop your 25p footage to a 30p timeline - but CAUTION - your NLE software will map out the footage frame-for-frame so you'd effectively be speeding up your footage by 20%. Depending on the footage it may not matter. Camera moves, or subject motion may look funny. Drop your PAL footage to an NTSC 30p timeline and give it a try.

2.) Interpolating. There are many different ways to come up with the 5 missing frames to get from 25p to 30p by interpolating processes but these usually result in some loss of perceived resolution, or can introduce some crazy artifacts. You can try a scripting process using AVIsynth and Virtual dub, but the easiest way will be to use Adobe After Effects and the Twixter plugin to do all that interpolation for you. Give the trial versions a shot and see if you like the result. This option will affect image quality for sure.

3.) Option three (and the absolute easiest) is to keep the project timeline at 25p and just shoot NTSC at 24p (not 30p). When you import your 24p NTSC footage to the 25p timeline it is effectively slowed down by 4% and turned to 25p. Your overall timeline shrinks by 4%, but it is so small (unlike 20%) that it will not be noticeable with any camera moves, or on the subject in your video. If you need sound to be sync'd then you have to also shrink your audio by 4% which can be done by adjusting the sound speed to 96% in most programs. (100% - 4% = 96%).


I've used PAL cameras to shoot 50i and go to 24p on prosumer cameras long before the advent of 24p in camera, so I know the ins and outs of these methods and feel I can provide you with realistic advice based on experience.

Let me know if you need any help... cheers,
 
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Hi Guys, on the same lines of this thread - I have a frame rate matching problem that I wonder if you can answer!? I have a HVX200 (UK) and want to match footage to a CS5 timeline that is a AVCHD 1080p 30fps (To match with other footage) - I filmed on the HVX with record settings of 720, 50p - then set the scene frame rate to 30fps. I hoped this would work....but the footage when brought onto the project bin is still showing as 50.00fps - it is playing back at the correct speed within the project but has stutter and motion blur. How should I best get this HVX footage into a 30fps sequence and retain the speed and quality (sound not required)? The film is of quite fast skiing so motion blur and stutter are causing me issues! (Oh, if i create a 50fps sequence and drop the HVX footage into it then yep it looks fine!)

Hmm, I hope you can shed some light on this issue too as we're stumped!
Cheers, Andy
 
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