using stabilize and the anchorpoints move to -193/16 on viewer

i using stabilizing track with single point, when i switch back to viewer, the video plane (at first frame) anchor move  to position  -193/16.

when i using double point stabilize in the viewer the anchor point move to -282/21.2

hitfilm4pro with current update, win7 uptodate, i920, gtx970 with newer driver

filming on ipad4 with minimal vertical movements. 

the same on hitfilm3pro. in this case, that must be normal.

Comments

  • The stabilization occurs in the Anchor Point setting, yes, and works by positioning the center point of your track at the center of the frame. If you offset your track's center point to be closer to frame center, then the video itself will be offset less. But the reason the track is applied to the Anchor Point is that this allows you to later use the Position setting to move the stabilized video around within your composition.

  • edited July 2016

    But slightly confusingly (if you don't know the underlying reason for it; which I don't) when you Transform a point from the Tracker it does that to the Position, not the Anchor Point.

  • Triem23Triem23 Moderator

    @Palacono the Anchor Point determines the "center" of a layer or model. Rotation, Scale and TRANSLATION (changes in POSITION)  center around the anchor point (a lot of techniques start with changing the anchor). 

    In the case of stabilizing a layer, you are telling the tracker to keep a point steady. This point is the new "center". Sliding the anchor point around is basically moving the layer around the point you slide the image around so the center stays on the tracked feature. This then leaves the user the task of re-centering and scaling the the footage. Therefore the anchor point is what needs to be moved. Otherwise, scaling the image up to fill the screen would destroy the stabilization since it would scale from center of frame, not the tracked point. 

    Changing the position of a layer is really moving the anchor point around. But, if the stabilization keyframes were made on Position then manually re-centering the frame would destroy the stabilization because now re-scaling the image would be around the incorrect point, unless you always scale first, then position. Which is restrictive and dumb! Manipulating the anchor is what allows translation and scale to be adjusted without destroying the stabilization. 

    Every point-track stabilizer changes an anchor point. 

    Now, an anchor point defines the "center" of an area or volume. A point has no area or volume, hencr has no anchor point. It's it's own anchor, therefore it has to alter position values. 

  • edited July 2016

    ah, thanks alot for the explanation,

    i found a "cheat", inserting the same value (transform) from "anchor" xy   to "position" xy, make my videoplane back on the center... so i have no black shapes around.

     

  • edited July 2016

    @Triem23 OK, that does make sense. There have been times when I wanted a 'reverse parent' option where I transform a point from the tracker, then want several things to follow it so they stay with the layer. Instead I end up using the layer itself as the parent to those other things (so text sticks to the video, for instance), but as I'm trying to train myself to use points for more things like that, it feels slightly kludgy.

    And, have you checked your PMs? I asked you a question. :)

Sign in to comment

Leave a Comment