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After Effects and Rotoscoping causes fps loss in info panel

Aug 30, 2010 3:06 PM



I am pretty new to after effects, so please take it easy on me if this is an easily fixed issue or if I am doing something wrong. Here is my whole process.


I have a canon xl2, shooting in 24p with 2:3 selected. I then import the video from the camera to premiere using capture. This was filmed at 16:9.

In PP I open a new project, I use DV - 24p Widescreen 48khz. I have the time code set to auto detect in capture.


I then import the captured video to after effects. I am trying to get better at rotoscope brush, so this is where the problem is.

I import the file, drag the source to the new composition icon, then double click the layer in the composition.  I select rotobrush and brush the object.

I then select play, which will go thru and play the file, adjusting the rotobrush. As I view the file, my info panel is up and it begins by showing 23.976 (realtime). The preview panel is showing 23.98 fps.

After a few seconds, the rotoscoping fails and the info panel shows my actual fps vs the file fps.  SO in red it shows something like 7.005/23.976 NOT realtime.


I've tried to do some research on this, and I am not sure if everything is set up right.  I have read that its best to work on noninterlaced video in AE, i believe it is seperating.  In interpret footage it is showing under fields and pulldowns area: lower field first and then it is removing pulldown with WWSSW.  Showing a effective framerate of 23.976.  Under frame rate area i have selected [conform to frame rate] and 29.97 is in the window. Under pixel aspect i have widescreen 1.21.


I know this is a huge wall of text, but I'd rather swamp you with info then not have enough.  Any ideas on what I am doing wrong? Why the fps drops out so much on the rotoscope? Also note, I am only losing fps after pressing play to have rotoscope find the edges itself.


Thank you for any help on this matter.


further info:

Running window 7 pro - 64 bit, adobe CS5 production premium. At the moment its the trial version - get my copy in the mail tommorrow.

PC is i7 920 oc'd to 3.6, 6 gigs ram, 7200 rpm HD with 64Mb cache, gtx480 with 1500Mb Vram. Using the latest Nvidia drivers. 

I believe I am using OpenGL for rendering, but not positive.

  • Currently Being Moderated
    Aug 30, 2010 10:58 PM   in reply to 50 Hungry Lions

    *sigh* Basics, people! Sorry to be so harsh, but it helps to read the manual (or the FAQ, for that matter):

    RAM previews pt. 1


    RAM previews pt. 2


    AE is not a video editing program, so its realtime abilities are limited (and for good reason).



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  • Currently Being Moderated
    Aug 30, 2010 11:51 PM   in reply to 50 Hungry Lions

    As Mylenium says, RAM preview (and other previews) won't necessarily be real-time in After Effects.


    Also, it's important to try to keep terminology straight. The Roto Brush tool accomplishes much the same thing as rotoscoping, but it isn't for rotoscoping, per se.


    If you're new to After Effects, I very strongly recommend that you start here and work your way through everything that it links to: eff.html


    There are getting-started resources in various languages here.

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  • Currently Being Moderated
    Sep 23, 2010 12:01 AM   in reply to 50 Hungry Lions
    >I  dont understand what you mean by this? I have been learning alot the  past few weeks, and I just came back to this post.  I am a little  confused by this statement.



    Rotoscoping is a tedious process of tracing frame by frame (usually drawing masks, but sometimes painting with a paint tool).


    The  Roto Brush tool makes that not necessary. You don't have to trace out a  shape on every frame; the Roto Brush effect does most of this for you,  automatically.


    The Roto Brush tool does what used to be accomplished by rotoscoping but in a totally different and more awesome way.


    It's  like a Jet Ski. It does something like a ski, but it isn't really a  ski. But the word 'ski' is in the name because it's evocative of what  the faster and more awesome device does.


    > From videos I've watched and things I've read everyone  calls it rotoscoping with the Roto Brush.



    Many, many people get terminology wrong.


    Again, rotoscoping is frame-by-frame tracing.


    If  you say "rotoscoping" around post-production people, they will think  that you're referring to the frame-by-frame drawing of precise masks  with the pen tools. If you choose to ignore my terminology advice,  prepare to confuse the people that you're talking to and have a harder  time getting help.


    The reason that I mentioned this in  the first place was because the way that you phrased your question made  it very hard to understand what you were actually encountering.


    Read this page on rotoscoping.

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  • Currently Being Moderated
    Sep 23, 2010 12:34 AM   in reply to 50 Hungry Lions

    > Is there a different term to use when creating a mask around an object with the rotobrush tool?



    Continuing to nitpick terminology:

    You don't create a mask with the Roto Brush tool. A mask is a path that is used to define an area (usually for ther purpose of making the area transparent). The Roto Brush tool creates a matte, but not a mask. In fact, a huge feature request that we get a lot is that people want the Roto Brush tool to create masks.


    That nitpicking actually brings me to the answer to your question: The correct way to say what you're doing with the Roto Brush tool is to say that you're creating a matte.


    Here's a page that distinguishes between these various compositing concepts and techniques:

    "Compositing and transparency overview and resources"

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  • Currently Being Moderated
    Sep 23, 2010 2:56 PM   in reply to 50 Hungry Lions

    Compositing...which is largely AEFX's purpose (a "Compositor")..often requires more than one technique to achieve a single result.


    It is not un usual to use multiple "techniques" and tools on one frame or clip.


    eg. You may use a garbage matte, a blue screen key, a rotobrush effect plus some rotoscoping etc all on one frame.


    The power of all tools /techniques in conjunction is the power of AEFX.


    No one tool replaces all the others is what I guess I am telling you here.

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  • Currently Being Moderated
    Sep 23, 2010 3:07 PM   in reply to shooternz

    >With all this considered, is there any reason why someone would do the traditional rotoscoping vs using the rotobrush to create a matte?


    To me it seems like the roto brush pretty much replaces traditional rotoscoping.  If thats the case, wouldn't it almost be considered a new rotoscoping method.


    Like in the past, people used to dig holes with shovels and by hand.  Excavating holes this way was hard and took alot of time.


    Over the years, technology made it possible to use a backhoe to dig holes, making it super easy. Both methods are excavating, one is just using an easier method.




    To expand on Craig's (shooternz's) answer and stick with your metaphor:


    Roto Brush is the backhoe. If you wanted to make a perfectly cube-shaped hole, you'd start with a backhoe and then do some finishing work with a shovel, spade, and trowel. Conventional rotoscoping is the shovel, spade, and trowel. I'd hate to dig a huge hole with them, but I wouldn't be able to dig a perfectly shaped hole without them.


    On the After Effects team, we talked a lot about what would be considered success for Roto Brush. We agreed that delivering a tool that could do 90-95% of the work was worthwhile, knowing that people could use other compositing methods to do the next 5-10%. Sometimes Roto Brush gets you all the way on it's own, but those are pleasant surprises.

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