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-   -   Pixel motion within a Premiere Timeline (https://www.dvinfo.net/forum/adobe-creative-suite/487673-pixel-motion-within-premiere-timeline.html)

Shane Lauf November 18th, 2010 12:43 PM

Pixel motion within a Premiere Timeline
Hi all --

Iím using the CS5 suite producing both PAL and NTSC DVDs of footage originally shot at 1080 30p. It's a series of both motion and still shots separated by crossfade, dip to black or dip to white transitions every 5 seconds or so. Roughly 5 min long.

Downscaling to standard definition NTSC is nice and easy but the challenge is PAL, obviously due to frame rate.

I'm familiar with pixel motion in after effects and would like to apply this to my timeline to do a 30p->25p conversion.
However I've found that applying it post-Premiere output (i.e. with all of the transitions in place) pixel motion gets utterly confused by the dips and so on.
On the other hand, most of those 5 second clips are taken from much longer source material so doing a HQ pixel motion conversion on the whole of every source file and rebuilding the entire project at 25p is not feasible for my hardware horsepower.

Is there a simple way to apply pixel motion (not just frame blending) to each clip in my Premiere timeframe, so that 1) pixel motion is processed before transitions and 2) pixel motion only has to work on the video data actually used in my clips not the entire source files?

Mike McCarthy November 18th, 2010 01:48 PM

Copy and paste your entire timeline into AE. (Select all the clips in you sequence and Copy, then go to AE, create a new Comp and hit paste) That should give you a diagonal stack of clips in AE, and you can apply Pixel motion to each of them. AE will process each clip individually with pixel motion.

Your transitions may require some tweaking, and for dip to black or white, I would remove the transitions and reapply them to the AE export in Premiere as a separate process, unless you want to use a white color matte in AE. For standard disolves, you can just keyframe the opacity of the higher layer in AE, to reveal the bottom one. (If copying your entire timeline fails, try bringing it into AE in sections)

Gregory Gesch November 18th, 2010 05:13 PM

Hi Shane. I may be wrong but my understanding is that any form of frame blending only works on a project which does not have an original frame for every composition frame, that is, it creates additional frames rather than have a frame repeat - which is not the case with a conversion of 30fps to 25. I would suggest you try taking the final 30fps vid into After Effects and put it into your standard NTSC project, then create a separate 25fps Pal Project and drag the NTSC Project into it as a precomp - ram preview and see if you have any problems (remembering that After Effects Projects are time based, not frame based, so you might find that you don't have any issues). I normally wouldn't suggest something without trying it for myself but unfortunately I live in PAL land - anyway my thoughts for what they're worth.

Shane Lauf November 24th, 2010 09:33 PM

Hi Mike -- I really appreciate your advice.
I've done the transfer to after effects as you explained and I do see the neatly arranged diagonal stack of clips.

Now I have a new problem however.
It looks like after effects is aware not only of the section of the clip that was actually used in my premiere project, but also of the entirety of the source files. For example for one clip where I was using the middle minute (1:00-1:59) out of the three minute clip, after effects "sees" the three minutes but only has the middle minute active. (I see this as lightly shaded box areas to the sides of the active clip section in the timeline, extending out to the full length of the source file).

So the problem arises in that the pixel motion effect calculates its frame position (the frame it takes as input) assuming that the entirety of the file up to that point has been speed adjusted, whereas in reality I only want to start the adjustment from the beginning of the active section.

In the example above, say I try and halve the frame rate (double speed) with pixel motion; well, when it looks at the first frame in the "active" part of the clip at 1:00, it thinks that the whole first minute before that has been sped up, chewing through two minutes of orignal footage -- and so it starts processing input frames from the 2:00 point in the original source file instead.

How can I make Adobe After Effects only "see" the clip from the point that I actually start using it in my premiere project? I've tried splitting layers and so on in after effects but it still sees where the source material starts.

Gregory> Appreciate your input. I think the question you are answering might be a little bit different to the one I'm posing -- I'm using pixel motion deliberately to avoid the problems associated with frame blending. But thanks for your help!

Mike McCarthy November 27th, 2010 05:37 PM

Once you have your new timeline in AE, instead of using the speed control settings, try using Time Remapping. Using time remapping keyframes to further modify your speed changes should avoid that problem, without having to override your in and out points.

Andrew J Morin November 30th, 2010 02:43 PM

But you want the speed to remain unchanged in the output, right?

I presume that you pasted the clips into a 30fps AE composition.
Change the composition settings to 25 fps, and you're done.
You can also change the resolution and ratios to PAL in that dialog, and then scale-to-fit the whole lot of your clips.
Sounds like you know, but be sure to enable frame-blending for the comp, as well as set each layer to pixel-motion...if processor power is limited, you can set that up in the render box instead so you don't have to wait for the frame-blends to process during scrubbing.

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