Latest post Tue, Nov 16 2010 7:33 PM by knejmann. 8 replies.
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  • Fri, Nov 5 2010 6:03 AM

    • Neophyte
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    Need help stabilizing a background with a foreground

    Hello everyone

    I was using a greenscreen in a few shots. The shots depict a psuedo police line up and includes several pans as people step forward and speak a few words. I used spectramatte key and successfully keyed out the green screen and added a background. As the camera pans the background and characters move out of sync with each other and give an unrealistic look. I've made several attempts using 3D warp and stablize to correct this problem but i'm inexperienced and it's my first time using stablize and 3d warp on something of this magnitude. ( i'm a student, hence the name neophyte)

     

    I've seen several tutorials many of you have been so kind to provide about stablize and would like so say that I have a good idea of how it works but lack the experience to make it work properly.

     

    Any help would be appreciated.

  • Fri, Nov 5 2010 10:10 AM In reply to

    • SussexJohn
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    Re: Need help stabilizing a background with a foreground

    Have you tried Region Stabilize?  I'm getting some very solid results with this tool

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    SussexJohn

  • Fri, Nov 5 2010 10:28 AM In reply to

    Re: Need help stabilizing a background with a foreground

    Do you have any tracking marks on the green screen? Some tape crosses or corners?

    Sounds like you need to extract the panning information with a track and then apply the same movement to an oversized BG plate.

    Honestly, I would always attempt this type of shot in After Effects where you have a more versatile toolset, although I dare say you could get decent results in MC if you are good with the tools.

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  • Fri, Nov 5 2010 11:18 PM In reply to

    • Neophyte
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    Re: Need help stabilizing a background with a foreground

    I haven't tried region stabilize but it ran across my mind as I was leaving school earlier today. I'll have to try it on monday and inform you on how well it works.

     

     

    No there are no markers at all on the greenscreen. Well unfortunately we don't have after effects at the school. Could you please explain to me how to extract planning information and apply the movement to the BG?

     

  • Sat, Nov 6 2010 1:59 AM In reply to

    • jwrl
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    Re: Need help stabilizing a background with a foreground

    Neophyte:
    unfortunately we don't have after effects at the school.
    I was going to suggest AE too.  It's a pity that you don't have it.  That's how I'd probably attack this problem.

    However there is always a plan B.  I'm assuming that the background is pretty static - it usually is with a line-up.  If you have access to Photoshop this will be easy, but really any art package should work.

    Export several individual frames of your background, making sure you cover the whole camera move.  Open them in Photoshop or similar and patch them together to make a single long panoramic frame.  Save it as a JPEG, PNG, Targa, whatever format file.

    Now in Media Composer import that art and put it in V1.  You will only be using this as a placeholder, so at this stage it doesn't really matter what it looks like.  Edit your foreground into V2 over the top of the still and set up your key.

    Drop an Avid Pan and Zoom effect on V1 and open your original source art inside the P&Z effect.  You will be able to pan across the full background width at full resolution.  It's now just a process of tracking your foreground moves inside P&Z.

    MC 7.0.4 - Asus P6T Deluxe V2 mobo - Intel i7 920 2.66GHz - Windows 7 Ult64 SP1 - nVidia Quadro FX 1800 - 16 Gbyte low latency DDR3 RAM - Internal 8 Tb... [view my complete system specs]
  • Sat, Nov 6 2010 3:07 AM In reply to

    • Neophyte
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    Re: Need help stabilizing a background with a foreground

    The background is completely static, it's just a high resolution jpeg.

    in V2 I have the greenscreen shots, the characters move and speak in these shots. This is where the panning occurs.

    In V1 I have a Jpeg. It's an empty police line up background. It currently has a 3D warp effect on it.

  • Sat, Nov 6 2010 6:58 AM In reply to

    • jwrl
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    Re: Need help stabilizing a background with a foreground

    Neophyte:
    The background is completely static, it's just a high resolution jpeg ... In V1 I have a Jpeg. It's an empty police line up background. It currently has a 3D warp effect on it.
    jwrl:
    Drop an Avid Pan and Zoom effect on V1 and open your original source art inside the P&Z effect.  You will be able to pan across the full background width at full resolution.  It's now just a process of tracking your foreground moves inside P&Z.

    MC 7.0.4 - Asus P6T Deluxe V2 mobo - Intel i7 920 2.66GHz - Windows 7 Ult64 SP1 - nVidia Quadro FX 1800 - 16 Gbyte low latency DDR3 RAM - Internal 8 Tb... [view my complete system specs]
  • Tue, Nov 16 2010 3:19 AM In reply to

    • Neophyte
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    Re: Need help stabilizing a background with a foreground

    I'm just about finished with the video. Here's a clip of the skit involving the background. I've been working on tracking but I haven't gotten it down. This is a version without tracking data and before I changed the height levels in certain shots. So please ignore them. What i'm having trouble with is simply the background motion.

  • Tue, Nov 16 2010 7:33 PM In reply to

    • knejmann
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    Re: Need help stabilizing a background with a foreground

    Pan&Zoom would give you the best background image quality but it allows neither tracking nor 3D rotation. Instead I think you should use a 3D Warp on the background and use tracking to control the position. If you have no tracking marks/targets on your (green screen?) background you'll have to do some experimentation to find the right (most static) targets in each shot.

    If you have more questions try to be a little more specific :-)

    The Avid MC Advanced FX manual has a whole chapter on tracking.

    Media Composer 2018.12.1 - Windows 10 - Dell 8520 - Blackmagic Decklink Studio 4K - Interplay and NEXIS storage - Avid Artist Color. Plus a lot of HP Z420... [view my complete system specs]

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    Aarhus, Denmark 

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