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  1. Member
    Join Date: Apr 2014
    Location: United States
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    Hi guys, I'm an aspiring entrepreneur and Iím trying to make a video showing a product concept Iíve got. To do this, I need take a video of a hand from a stationary camera and crop it out into its own video. I then need to convert that into a shadow and paste it over another video.

    Iím an electrical engineer and Iím pretty computer savvy, but Iíve never done anything like this before. Is there free software that you could recommend for performing this that wouldnít take too long to ramp up on?
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  2. Member
    Join Date: Sep 2007
    Location: Canada
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    Originally Posted by zachavm View Post
    Hi guys, I'm an aspiring entrepreneur and I’m trying to make a video showing a product concept I’ve got. To do this, I need take a video of a hand from a stationary camera and crop it out into its own video. I then need to convert that into a shadow and paste it over another video.

    I’m an electrical engineer and I’m pretty computer savvy, but I’ve never done anything like this before. Is there free software that you could recommend for performing this that wouldn’t take too long to ramp up on?


    Probably After Effects

    You said camera is stationary (I'm assuming locked off, so no axial rotation) , but clarify the "hand" -

    Is it attached to a body?

    Is there motion? What kind of motion ?

    What kind of shadow? Is it opaque? color? what degree of transparency (do you see parts of the other video "underneath") ?

    What kind of "paste" ? (are you pasting stationary, or does the shadow move and track? )
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  3. Member
    Join Date: Apr 2014
    Location: United States
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    the camera will be stationary and looking straight down on a table where a hand that is using a tablet. It will be moving. Unfortunately, the screen on the tablet will be moving as well. However, I can turn the brightness down as much as possible.

    Once the hand has been cropped into it's own video, I simply want to make the entire image a single block color. I guessing from that point it should be easy (relatively of course) to make it the right color and transparent.

    I will likely need to crop the video of the hand, but it should remain stationary at that point in relation to the video I would be overlaying it over.

    Hopefully this is enough information. Thanks so much for the help!!!
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  4. Member
    Join Date: Jun 2012
    Location: USA
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    If your demo-ing something on the tablet, why not turn the brightness up, expose for that, turn off all other lights, let the hand go dark and just do it live?
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  5. Member
    Join Date: Apr 2014
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    Originally Posted by smrpix View Post
    If your demo-ing something on the tablet, why not turn the brightness up, expose for that, turn off all other lights, let the hand go dark and just do it live?
    It's a little different than that. The video work is necessary for the product, but your suggestion could make it easier to pull the hand from the video.

    I'm sorry I'm being so vague, I just don't want to talk to much about what it is for here in an open forum.
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  6. Member
    Join Date: Sep 2007
    Location: Canada
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    So are you demoing the tablet ? What is the purpose of the hand and shadow ?

    In terms of methods of doing this - The "gold standard" is rotoscoping - basically you draw points around the hand to isolate the hand. It's done frame by frame, but there are interpolation in software (so not every frame is required to be manually done). There are other assist tools like motion tracking, edge finding algorithms. It's the most accurate, but it's also the most tedious and usually the "last resort" method used

    Depending on the framing of the hand on the tablet (where the overlaps are, if the hand lies entirely in the frame of the tablet) - an easier method would be to display a green screen on the tablet and you can chroma key out the tablet screen, leaving the hand. Garbage mattes are easy to do around the periphery

    And I missed the "free" part of your requirement... There are free chroma keyers e.g. cinegobs, blender (steep learning curve) , aviutl, and a free rotoscoper would be claxa, blender as well

    A "shadow" implies that you don't need extreme accuracy or a perfect job of the edges, so you can probably get away using other methods than rotoscoping

    Unfortunately the vagueness prevents people from helping up with better custom solutions or options .The details are important and distinguish what you might be able to do this with either in post production with software , or with an acquisition technique
    Last edited by poisondeathray; 19th Apr 2014 at 14:11.
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  7. Crude, simple, lay down a green cloth, outdoors, let the hand cast a natural shadow.
    I am not responsible, and it's been proven over and over again.
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  8. Member racer-x's Avatar
    Join Date: Mar 2003
    Location: 3rd Rock from the Sun
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    Originally Posted by sum_guy View Post
    Crude, simple, lay down a green cloth, outdoors, let the hand cast a natural shadow.
    That's a good suggestion. No need to be exact, you can adjust in post. As for free s/w, I'd also recommend AviUtl. Nothing dificult here....it's just a question of your abilities and resourcefulness.
    The memories of a man in his old age, are the deeds of the man in his prime.......
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  9. I agree with racer-x, Aviutl would be an excellent choice for an editor. free and a lot easier to use than blender or some of the other editors.
    I am not responsible, and it's been proven over and over again.
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  10. Member racer-x's Avatar
    Join Date: Mar 2003
    Location: 3rd Rock from the Sun
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    Actually, if all this is a demo on a Tablet app functions, you can just use a picture of a hand with index finger shadow and animate it over any screen you want. Otherwise go with the geen cloth idea.
    The memories of a man in his old age, are the deeds of the man in his prime.......
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  11. Member
    Join Date: Sep 2007
    Location: Canada
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    Or your hand model could wear colored gloves and chroma key that. Color doesn't have to be green
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