How do I create a matte that tracks with movement in the scene?

I am doing a teaching video for a software company.  The instructor is demonstrating how to build a website (using a drupal backend).  The instructor is describing how to create an article by pasting text into a form box, and then how to format the text.

The instructor pasted the wrong text during the recording.  I've fixed these errors in the past by requesting they give me a new screen capture with the proper text, and then I've essentially created an animation of that section of the lesson by overlaying an image of the proper text and then... (ack!!) keyframing an image of their cursor making the mouse movements, making sure the mouse ends up at the exact location where the error-footage ends.   Did I explain that one clearly?

It's all very smooth and  you'd never spot the fixed inserts.  But in this project, the instructor pasted the wrong text in the form field, and then scrolled vertically to show something higher on the page.  So, I need to create a matte of some sort to insert the new footage of the form field, and then have the matte/inserted footage track with the  scroll.

In this instance I can't animate the mouse movements because there is a lot of highlighting and formatting. Fortunately, the size of the interface elements is exactly the same in the original and the new footage.


  • Triem23Triem23 Moderator

    So track a point on the page he scrolls then parent your insert layer to the tracked point?

  • edited June 2017

    I've watched many tutorials on tracking, but it's new to me.  I'm not understanding how/whether to implement a point layer first.

    Also -- is it better to have the matte cut a hole in the video (in which to insert the new footage) or should I have the matte clip the replacement footage and then place it in a layer on top of the original?

    As always, I'm grateful for your assistance.

  • I'd cut out the replacement part in a separate Image program, so it's only the size of the part you want to replace. No Mattes required.

    If you don't want to do that, then put it in its own composite and Matte it there and embed that comp in the one with the background video.

    Track the top left corner of the thing you are overwriting and apply that to a New Point. Put the Overlay (image/comp) on a layer above that and at the correct location at the start of the track and then Parent it to the New Point.

    If you Parent it at a different time you'll have to adjust its position when you do Parent it, so put it in the right place first.

    Then you have your other overlay for the cursor on top of that, clipped to start and stop only when it needs to.

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