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Interpret composition? (Not footage)
Subject says it all.
Here’s my specific situation. I’ve got some film footage as a 29.97fps mpeg2. I want to be able to do some noise reduction on this footage. But I also plan to remove pulldown and get a 23.976fps video out of it.
After Effects lets me do both of these things. But I can’t seem to do them in the right order. It lets me interpret the footage to remove pulldown. That works. And I can apply an adjustment layer to footage for noise removal purposes. But what it doesn’t seem to want to let me do is interpret a composition.
In this case, I want to remove noise FIRST, and THEN remove pulldown. Why? Because removing pulldown complicates the noise by interlacing it at intervals, which in turn causes the noise removal to be both less than ideal and less than consistent.
And it is a mystery why I can’t “interpret footage” on a composition, because there’s nothing stopping me from, say, rendering my noise-reduced comp as RAW, and then interpreting THAT.
So am I missing something?
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4 Replies
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Okay. Actually, my old AE CS4 handles the mpeg2 footage quite well.
But if you’re saying that the reason I can’t interpret my 29.97fps comp as 23.976 with pulldown removal (the option is grayed out) is specifically because it contains interframe video, well, I suppose that’s that.
Seems a bit odd, though. As I said, I do not experience any anomalies which would suggest AE is freaking out over the footage. I have even loaded the AE comp up into PPro, and even that kind of boat rocking hasn’t generated problems.
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Pretty simple, actually. The noise in question is largely of the mpeg2 mosquito and megapixel variety. These artifacts are of a consistent nature on their individual frames – ie the two fields of an interlaced frame, which are stored as two half-frames in one image.
Any kind of interlace-related modification to these frames (pulldown removal, for example) will chop these megapixels into an interlaced weave of artifacts. If a noise reduction effect is designed to work on whole frames (meaning both fields in a frame), it should be obvious why allowing such interlace manipulation prior to the noise reduction would complicate matters. Instead of working its magic on predictable noise, it has to deal with noise that has been woven together at the finest vertical level.
Perhaps this might help: Have you ever seen a video that was encoded while still being interlaced? It just doesn’t work out too well. There are reasons.
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Nah, what I meant was, say, XviD or Divx compression on progressive video which happens to consist of interlaced frames – both fields already interwoven. The reason this gives a poor (and more importantly, less than ideal) result, as well as the fact that such a result is intuitable, is similar to the reason why noise reduction in my case is also less than ideal if done in the wrong order.
In my frank opinion, the “remove pulldown” feature in After Effects should have been something one could put on an adjustment layer, not a one-shot process that has to be done at a specific point in one’s workflow. In terms of its ultimate purpose, it differs little from similar effects like Timewarp. The fact that I’m having to resort to the good ol’ raw video to get my job done attests to the validity of this opinion.
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No argument. If I had a raw 1080p file in front of me, I’d be rather happier. Unfortunately, what I do have is a DVD encode of a VHS tape.
Anyway, it looks a lot better now that I’ve gone through the considerable hassle of rendering off a 130GB raw file. I again question the wisdom of tucking pulldown removal away as a file interpretation rather than a temporal effect (or, ideally, both, so long as the need for raw renders is minimized).
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