Need help with Motion tracking and behaviors for film

Discussion in 'Digital Video' started by Zwhaler, Mar 16, 2012.

  1. Zwhaler macrumors 604


    Jun 10, 2006
    I have little experience with Motion, but basically what I am seeking to accomplish is to take a shot that I have panning across the front of a movie theater sign showing the current movies that are out, and edit that shot with my own custom title so that the theater sign shows different text that I put in. Now, if I simply overlaid a title then some of the original words beneath might still show, so I'm thinking I might fit a generator over the original text and motion track it with the custom title on top of it, so there would be two layers, both motion tracked. I found some help pages on this subject from Apple but would like some feedback from fellow users/editors detailing how to go about this process. Motion 5 and FCP X here. Thanks for any suggestions & info.
  2. floh macrumors 6502

    Nov 28, 2011
    Stuttgart, Germany
    First: I hope you did not pan very far. :) Otherwise, you are going to have significant 3D movement happening to your sign. Motion can only do 2D tracking, which is fine for many things but might fail (i.e. look very unrealistic) for extensive camera movement. In this case, you will probably need a 3D match moving tool. If so, let us know and we'll point out some.

    Second: If you have already mastered the tracking with simple text and are just annoyed by the background, you can always just create the complete sign (background and text) in some graphics programm and have that be tracked in Motion. Unless you want the text animated in some way...

    Third: I am absolutely not a Motion expert, but I can remember there is a simple way to motion track several objects or layers to a single path:

    You select the source footage and choose Behaviours->Motion Tracking->Analyze either from the Library tab or directly from the "Behaviours" button with the little cogwheel above your timeline. You can then add multiple tracking points with high contrast and analyze the motion. You will then have a track attached to your original footage.

    Now create your sign background and your text. To both those layers, add the tracking behaviour by selecting each one and then choosing Behaviours->Motion Tracking->Match Move from the library tab. Now assign the source of this match moving to be the Analyze path you created earlier. Select the match move of an object and switch to the Behaviour tab in the Inspector. Do not create a new tracker and analyze the motion again, but rather just choose the already created tracking path as source. To do so, either choose your path from the small cogwheel next to the "Source" property of your Match Move, or just drag and drop said path to the small window next to source.

    As I said, I don't have huge experience with Motion, but this definitely worked for me. Oh, I just found a very simple youtube tutorial on exactly this kind of motion tracking:
    Simple Motion Tracking with Motion 5

    Fourth and maybe most simplistic: Just put your Text and sign background in the same group and have the whole group move with the background. I haven't tried it, but I'm pretty sure this would also do the trick.

    I hope all my menu entries were usable (my version of Motion is German, so I can't check...) and I could help some.
  3. wonderspark macrumors 68040


    Feb 4, 2010
    I'm an After Effects guy myself, but you need to mask over whatever is already on the theater marquee, because yes, it will show through.

    That will mean adding new lines between rows of lettering for realism, as the letters on a marquee sit in little slots that you can see. Best to create a whole new marquee image (black letters on white lit marquee panel with the faint lines and everything) and track that.

    I'm willing to bet you'll have some distortion to contend with as the sign moves across the lens aberration from one end of the frame to the other.

    It might sound crazy, but if you have Photoshop, you can open video footage with it, edit it frame by frame, then render back to same file with changes intact. I once removed wires from a shot that way.

    Sounds like fun!
  4. handsome pete macrumors 68000

    Aug 15, 2008
    If he only did a pan, then a 2D tracker would be perfectly suited for the job. There's no parallax in panning so there's no real change in 3D perspective.

    Now if it was a dolly/tracking shot, that would be a different story.

    I mostly use AE so I haven't used motion in years. But even if you watch some AE tutorials on 2D motion tracking or sign/text replacement you should get a good idea on the principles of the process. That should help you accomplish it in motion.
  5. Zwhaler thread starter macrumors 604


    Jun 10, 2006
    Thank you all for the replies, the shot had minimal panning at a slow speed... I'll get to work and follow the steps posted and also check out that YouTube video. :)
  6. Zwhaler thread starter macrumors 604


    Jun 10, 2006
    I managed to complete the project going off of your guys advice, so thank you. I used a combination of motion tracking and keyframe editing to smooth out the nuances (small rotation and x,y axis transformation keyframe editing) and it looks great for my first motion project. I look forward to discovering what else I can do with this application.

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