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Rendering fields takes twice as long as progressive?
Hi all,
I’m probably going to answer my own questions here, but steer me in the right direction if I’ve got it wrong…
I’m currently working on a composite consisting of a blue screen shot, which I have keyed (using autotrace+keylight) & CC’d (4 diff fx combined) This is over a backplate of footage which I’ve also CC’d and applied a 400% timewarp with pixel motion.
Now, it is a 10 second comp and I initially rendered it progressive, forgetting that I’d separated fields on my key subject – so the render doesn’t look right. I’ve now gone back to render it UFF and it’s taking twice as long as prog (1hr vs. 30 mins) Is this because there’s twice the resolution of footage being rendered, or just because fields take longer to render than whole frames?
My footage was shot 50i on HDCAM, I have captured it downconverted to SD. The back plate I *didn’t* separate fields in AE, as I’ve heard you get better timewarp results with interlaced footage(?) Question 2 – should I have separated fields on back plate? And as I haven’t has AE done anything untoward to it because I rendered progressive?
Sorry if this is a garble..If I haven’t explained anything properly let me know!
Thanks muchly.
*Production Studio Premium / *Combustion 3
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3 Replies
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When AE renders fields – it renders them as separate frames, then muxes them together. If you detail a render in the RQ – you will see it rendering frame 1U then rendering frame 1L (for upper and lower).
The render engine treats them almost as if they are completely separate frames – hence double the time. (not counting pulldowns etc – thats a whole topic)
Steve
GridIron Software Inc. -
Knackers…so doing anything interlaced is going to yield results in twice the amount of time to progressive then? That gives even more of an arguement to shoot everything in 25p!
I’d not really thought about it before – I do mostly gfx-based work that lays over interlaced footage with alpha in a separate NLE. I always render gfx progressive.
Treating interlaced footage directly in AE, it seems, is a very slow process then. Oh dear. Either that or trying to deinterlace and combine fields for any footage that comes in and put it all out progressive..again, another very time consuming process. Plus I guess it won’t match any other shots that it’s up against if they are fielded…
Any other work arounds guys?
*Production Studio Premium / *Combustion 3
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Win XP Pro SP2 / Intel P4 3GHz / 2GB RAM / GeForce FX5200 / DeckLink Pro / Roland DS-5 monitors / Sony BVM-20G1E / DVS SDI Clipstation / 110GB boot/80GB media/600GB RAID-0 -
You could re-time 15p to 30i but I wouldn’t recommend it–it will not look good. I think you’re stuck. There are some graphic programs (usually 3D renderers) that will only render the lines in each field and then combine them to make one interlaced frame but AE is not capable of doing this.
Jim
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