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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?

786 Views   8 Replies   Latest reply: 12padams, Apr 19, 2012 12:44 AM
 
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  • Mylenium
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    1. Mylenium,
    Apr 18, 2012 9:21 PM   in reply to 12padams
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    Effects --> Keying --> Difference Matte

     

    Mylenium

     
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  • 12padams
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    2. 12padams,
    Apr 18, 2012 9:29 PM   in reply to Mylenium
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    When I applied that effect to the top layer it simply halted movement all together ... It didn't make a mask :(

     
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  • Mylenium
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    3. Mylenium,
    Apr 18, 2012 9:34 PM   in reply to 12padams
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    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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  • 12padams
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    4. 12padams,
    Apr 18, 2012 9:42 PM   in reply to Mylenium
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    Yikes! That sounds complicated...

    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?

     
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  • Mylenium
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    5. Mylenium,
    Apr 20, 2012 4:01 PM   in reply to 12padams
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    Start here.

     

    Mylenium

     
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  • Andrew Yoole
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    6. Andrew Yoole,
    Apr 18, 2012 10:13 PM   in reply to 12padams
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    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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  • Rick Gerard
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    7. Rick Gerard,
    Apr 18, 2012 11:46 PM   in reply to Andrew Yoole
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    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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  • 12padams
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    8. 12padams,
    Apr 19, 2012 12:44 AM   in reply to 12padams
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    Thank you everyone

     

    I will now go through a bunch of video tutorials in order to improve my basic skills. I have enough knowlege to do certain things but other things just annoy me with their mysterious functionality.

     

    I am sure you all know what your talking about so I guess this is "resolved".

     

    Thanks to everyone!

     
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