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Frame blending using pixel motion: method used to go from progressive to interlaced footage, clean

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Esther Casas
Frame blending using pixel motion: method used to go from progressive to interlaced footage, clean
on May 5, 2014 at 10:02:09 pm

Hi all!

Ok, I have a situation: I have a progressive QT (1080 29.97fps) movie to deliver as interlaced (1080i 29.97fps). The footage has some stop-motion and pixelation effects...so I was told that if I simply add this QT into fcp7 and export as interlaced or also I do it through compressor, my QT interlaced it will be not as clean as my original one because of this pixelation effect I am doing.

So, I was told to use the pixel motion effect from After Effects to double my frames the cleanest way. There is a tutorial around this forums, but it doesn't really explain how to really use this effect , I am having trouble understanding how my frames will be double it, what I am doing:

importing QT into a new sequence, then Layer > Frame Blending > Pixel Motion, then what do i do? I guess I have to double the duration of my sequence, but then how does AE creates these extra frames? I need the clip rendered with twice the frame count...

The tutorial explains steps after frames are already doubled it, but can't figure this out...WITHOUT USING FRAME BLENDING though..

can somebody help with this extra step? thank you so much everybody!!!


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Dave LaRonde
Re: Frame blending using pixel motion: method used to go from progressive to interlaced footage, clean
on May 6, 2014 at 12:12:28 am
Last Edited By Dave LaRonde on May 6, 2014 at 2:13:52 am

That's a lot of work! You should have to do almost NOTHING. Seriously.

Here's how simple it really is: put your progressive video into an AE comp, then render interlaced. Since the video is 1080, set the field order in the AE Render Settings to UPPER FIELD FIRST, and NOT lower field first. That's it. Very easy.

Will it look good on a COMPUTER monitor, which doesn't like interlacing? Perhaps. Will it look good on a TV set, which is made to work with interlacing? Yes. And it is indeed on a TV set -- or a VIDEO monitor -- where you should do the judging. Computer monitors hate interlacing.

I understand people rarely work with interlaced video anymore, but jeez, this stuff really isn't brain surgery.

Here's an explanation that works in 1080-Land; 720-Land is a different story.

At 1080, some cameras allow you to shoot progressive or interlaced video. If they do, EITHER WAY YOU SHOOT IS RECORDED AS INTERLACED. No fooling. Here's how they do it:
When shooting interlaced, the camera scans one field and records it, then scans the second field and records it. The two fields make one frame... but each field is separated in time by a tiny amount. Doing this has the virtue of giving you smoother-looking motion, but you need to watch it on a device that's made to diplay interlacing. However, that tiny time difference between fields manifests itself in sections with fast motion. That's why you see those ugly lines when you look at interlaced video on a computer monitor, and why it looks worse if the subject moves faster.
When shooting progressive, the entire frame is scanned at the same instant... and THEN it is recorded as two fields. There is NO tiny separation in time between the two fields. You lose the smoother-looking motion of interlaced, but it looks fine on either a video monitor or a computer monitor.

Well, your source video is progressive. If you add interlacing, what is the source for those two fields? One frame, scanned & recorded at one instant in time. Thus, your fields will be from the same instant in time. It will still look progressive... because its source is progressive.

Now, if you WANT to create the smoother motion of interlaced video from progressive video -- and I stress the word "want", because it isn't necessary from a technical point of view -- you have to create intermediate frames of progressive video, recreating the missing intermediate motion. For 29.97p, this means using something like Twixtor to generate those new intermediate frames, creating at 59.94p file... which you can then use to create an interlaced 29.97 file. Or that recipe you found. That's a lot of work which I feel is't called for!

But if you just want to make your existing video interlaced, it's pretty much a no-brainer: just follow the procedure above.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Esther Casas
Re: Frame blending using pixel motion: method used to go from progressive to interlaced footage, clean
on May 6, 2014 at 1:18:42 am

Hello Dave!

I will try your suggestion tomorrow once I am back in AE...but I was referring to this post, where apparently, if you do what he is saying, you have a clean/real interlaced footage,and yes, i need it for broadcast, the method I wanted to try out with pixel motion in AE is this one:

http://library.creativecow.net/articles/solorio_marco/interlacing_progressive_footage.php


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Dave LaRonde
Re: Frame blending using pixel motion: method used to go from progressive to interlaced footage, clean
on May 6, 2014 at 1:41:46 am

Well, if you want to, fine. I see no need for it. If I had progressive video I was happy with, I'd just add the interlacing, which is dead simple.

IT WILL BE FINE, AND YOU DON'T HAVE TO JUMP THROUGH HOOPS TO DO IT.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Kevin Camp
Re: Frame blending using pixel motion: method used to go from progressive to interlaced footage, clean
on May 6, 2014 at 5:18:24 pm

i'm with dave. i don't think you'll have any problems simply rendering your 29.97p footage as 59.94i without adding the frame blending.

if you were mixing footage and/or graphcis that were where some was interlaced and some was progressive, then you'd like to make them all the same (either all interlaced of all progressive), but since it sounds like you have one piece that's all progressive, i don't think you'll need to worry about it.

that being said, if you want to do the frame blending trick, drop the footage into a new comp. enable pixel motion frame blending for the footage layer, add the comp to the render queue, click the render settings (probably says 'best') and in the field rendering setting choose upper field and render.

the output will be interlaced.

one pitfall with this method is if there are cuts in the piece, the interpolated field created by the pixel motion will be garbage. it may not be too noticeable at playout speed (heck it's only 1/60 of second), but it may be an issue. the only way to get rid of that issue is prior to rendering with fields you need to split your clip at each cut (move the cti in the timeline to the frame after a cut and then hit command-shift-d). once you've done that at each cut, render as with fields and you should be good.

Kevin Camp
Art Director
KCPQ, KZJO & KRCW


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Esther Casas
Re: Frame blending using pixel motion: method used to go from progressive to interlaced footage, clean
on May 6, 2014 at 5:52:47 pm

Thanks Dave,

now I am thinking, if I am just rendering as interlace from AE, why don't I do that from FCP7 already? So exporting the progressive QT and re-importing into an interlaced sequence, isn't this then the fastest and easiest way?

what would be the difference from doing it from AE and FCP7?
thanks again!


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Dave LaRonde
Re: Frame blending using pixel motion: method used to go from progressive to interlaced footage, clean
on May 6, 2014 at 5:56:25 pm

FCP, huh? I don't see why you couldn't just export from the FCP timeline. To what codec do you need to compress this?

We already know the frame rate & resolution.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Esther Casas
Re: Frame blending using pixel motion: method used to go from progressive to interlaced footage, clean
on May 6, 2014 at 6:08:57 pm

I will actually be editing in AE too...I am thinking to do all my effects and frame cuts in AE, and export from there a progressive QT.

Then importing into FCP7, and exporting upper filed dominance from FCP, how does this sound?

I need to deliver 1080i 29.97fps, ProRes(HQ) for broadcast


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Dave LaRonde
Re: Frame blending using pixel motion: method used to go from progressive to interlaced footage, clean
on May 6, 2014 at 9:59:31 pm

If you're just trimming up clips, AE should be okay. But if you're talking about anything longer than a few minutes, removing massive amounts of extraneous video, doing matched-action cuts, split-track edits, etc. you've picked the wrong editing application.

There's only one video editing application I can think of that's worse than AE: Microsoft Word.

If you have a lot of editing work to do, you will be far better off doing it in FCP and importing into AE. You'll save a LOT of time because FCP is intended to do video editing, and AE isn't.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Esther Casas
Re: Frame blending using pixel motion: method used to go from progressive to interlaced footage, clean
on May 6, 2014 at 10:15:31 pm

Hi Dave!
I am actually doing compositing with AE and other stuff that can only be done in AE..

The editing cuts in fcf7, and from there i was thinking to export to interlaced, so I don't need to go back to AE, correct?
I think is the easiest workflow to export interlaced from FCP7, if is really exporting as such for broadcast..

This is all I need to know, if I can trust exporting interlaced from FCP from a progressive footage placed into an interlace sequence?


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Dave LaRonde
Re: Frame blending using pixel motion: method used to go from progressive to interlaced footage, clean
on May 7, 2014 at 12:01:32 am

The normal workflow is to edit in a video editor, do effects work in AE, and then back to the video editor.

You can judge for yourself if that will work for you. You won't be making any grave technical errors, it's a matter of the most efficient use of one's time.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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