Activity › Forums › Adobe After Effects › roto-brush on very long clip
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roto-brush on very long clip
Posted by Tom Ma on January 4, 2011 at 10:34 pmI have a 30 MINUTE long clip in HD: static talking head on city scape BG.
I need to color correct the BG, but keep the FG.
I am experienced with keying and any procedural keying is not doing as good of a job as roto-brush, but on a single frame.Is it feasible to use roto-brush on a clip this long?
It seems roto-brush caches to RAM. There is no way I have the RAM for this (but have plenty of HDD storage to disk-cache if needed.)
What would be the best work flow? Split into smaller clips, then recombine?
It is an easy ley for roto-brush, basically, how do I set it, and let ‘her rip?
Randall Martin replied 15 years, 2 months ago 5 Members · 9 Replies -
9 Replies
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Todd Kopriva
January 4, 2011 at 11:48 pm> Is it feasible to use roto-brush on a clip this long?
Yes.
> It seems roto-brush caches to RAM. There is no way I have the RAM for this (but have plenty of HDD storage to disk-cache if needed.)
What would be the best work flow? Split into smaller clips, then recombine?
It is an easy ley for roto-brush, basically, how do I set it, and let ‘her rip?You’re correct that Roto Brush does cache results to RAM, but I think that you might be making a leap to an incorrect conclusion.
The worst case is that you run out of RAM for the cache, and Roto Brush throws away the information that it has cached. That just makes it take longer when you go back to revisit a frame (say, to make a corrective stroke). It doesn’t mean that the matte result is discarded.
You certainly don’t need to split the layer into multiple layers.
You could use multiple spans, though. (If you’re not familiar with spans, be sure to read this part of the documentation.) You don’t even _need_ to use multiple spans, but it can make your workflow easier if you need to revisit frames, since the longest time that you’d need to wait for recalculation upon revisiting a frame would be decreased.
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Rick Zeimann
January 5, 2011 at 12:35 pmI’ve been working with the roto brush a great deal of the past few months and picked up a few tricks.
I’m running AE CS5 in Windows 7 with 12 GB RAM using two dual i7 cores, and the roto-brush freeze wait time is significant when my clips are over 7 seconds. Generally, I break all my clips into 4 second roto-brush spans in order to reduce the brush calculation wait times when freezing roto’d clips.
Good luck on your project.
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Tom Ma
January 5, 2011 at 8:40 pmyes, this is an issue. As I mentioned, my clip is very long, shy of 30 minutes… and in HD 2997 (LOTS of frames)
I am a little confused on how this is processed and workflow…
Over the course of the clip, I “painted” a few “keyframes” which created spans. Do I need to “propogate” these frames or internally process them before I can send this thing to the render que for my matte?The mattes look great on the keyframes I set, I just need to render the sucker out and get my matte.
I did send off a render, but I have had a spinning ball now (system processing) for over 12 hours! Nothing listed in the AE info panel.
I would have forced quit, but OSX is telling me the app is indeed responsive, and not crashed. Perhaps processing??Basically, now that I have my keyframes set, how do I get a render out?
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Mike Houston
April 17, 2011 at 3:11 pmThe documentation states this: “To manually change a span duration, drag either end of a span.” So once you have dragged the span, to equal the length of your clip, you have to spot check it to make sure that it’s correct, then freeze it, then render it. I had to do a 7 minute clip like that yesterday, because my “black background” wasn’t infinity black. It’s a bit tedious, but I had great results. Don’t always trust the flip out monitor on your 4:2:0 camera. LOL
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Randall Martin
May 6, 2011 at 5:53 pm“Little arrows in the span bar in the Layer panel show the direction in which the information is being propagated.”
The only arrows I can find, are when I hover over the “little orange square” and they point in both directions.
I have AE CS 5….
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Randall Martin
May 6, 2011 at 6:11 pmI probably have a “dingbat” brain, so I have no idea what a dingbat type face is. Whatever, it is on two computers, one running Windows 7, 64, the other Vista Ultimate 64.
Help!
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Randall Martin
May 6, 2011 at 8:56 pmContinuing with my dingbat brain.
I assume I have to find a font that has “liitle arrows” and then install it in adobe?
Why wouldn’t such a font already be installed when they refer to the arrow?
Thanks for your help.
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Randall Martin
May 6, 2011 at 10:58 pmIn the windows fonts, which supposedly AE CS5 uses, there are at least two which have arrows, U2910 and U2192: Arial narrow, and Lucida Console. Nevertheless, no arrows appear in the places they are supposed to in the layer panel.
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