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12padams
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Auto generate mask from motion?

Apr 18, 2012 9:10 PM

I have a clip of a person walking around a scene and a clip without them walking around(the background). I want to apply a different color to the walking person so I will obviously need a mask around them on the top layer. How can I auto generate a mask of the moving person instead of frame by frame mask readjustment?

 

Is there a track motion and auto move mask tool?

 
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  • Currently Being Moderated
    Apr 18, 2012 9:21 PM   in reply to 12padams

    Effects --> Keying --> Difference Matte

     

    Mylenium

     
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  • Currently Being Moderated
    Apr 18, 2012 9:34 PM   in reply to 12padams

    I'm not clear what you arte doing. Yes, it only creates a matte, not a mask. If you need masks, you can still use the diffetence matte, pre-compose, then auto-trace.

     

    Mylenium

     
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  • Currently Being Moderated
    Apr 20, 2012 4:01 PM   in reply to 12padams

    Start here.

     

    Mylenium

     
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  • Currently Being Moderated
    Apr 18, 2012 10:13 PM   in reply to 12padams

    12padams wrote:

     

    Yikes! That sounds complicated...

    Welcome to the world of motion graphics and compositing.

     

     

    Basically I have a blank room video layer at the bottom. Above that I have transparent footage of the same room with a person walking across. I want that footage on the top layer to be a moving mask that follows only the person. Then I want to apply an effect to that moving person mask and make then blue (they are already transparent). Is this possible?

    Sorry, your terminology is a little vague, so it's not clear what you have or what you are trying to achieve.  What do you mean by "Transparent footage"?

     

    I'm assuming you have a back plate of your room environment, plus a second layer of footage which contains a person walking around in the room - framed exactl the same.

     

    As Mylenium said, use the Difference Matte effect to generate a matte of the walking person.  You may be able to directly use the matte for your purposes and just key the character out of the background.  If you truly need a mask, you will need to use the Auto Trace function to generate the mask from your matte.

     
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  • Currently Being Moderated
    Apr 18, 2012 11:46 PM   in reply to Andrew Yoole

    For difference matte to work the frames must be nearly perfectly identical.  That means absolutely no camera movement. That means no compression artifacts in the footage. That means high bit depth, high data rate video.

     

    If your footage was shot with a DSLR you are probably out of luck. If your footage was shot with a consumer camcorder, you are probably completely out of luck. If your footage we shot on a professional camera and captured at a high data rate, you may have a chance.

     

    A sample frame of the movie from a screenshot will help us determine if you have any chance at all. Even better, post the video to YouTube, and give us a look.

     

    If the footage will work, all you need do is load both clips in the timeline window, then, apply difference matte to the footage with the actor. Turn the visibility off on the background layer, then reference that layer in the difference matte.

     

    You will end up with a keyed out actor. You can then do whatever's necessary to complete your project.

     

    Let me say once again, difference matte is a real picky plug-in. Any pixel that is not exactly like the pixel in the background source will not be transparent. That means any noise in the frame spoils the matte.

     

    Good luck on your project.

     
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