Compensating for camera skew

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tanguero
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Compensating for camera skew

Post by tanguero »

I'm a new user (on the trial version of X7). I have a video where the camera was set up on a tripod about 8 degrees off. Now this should be an often-enough occurrence that I'd think there'd be single simple filter to compensate for this. What I want to do is:

- Rotate the picture 8 degrees clockwise (i.e., 352 degrees counterclockwise)
- Auto-crop out the 4 black "triangles" created by the rotation at the edges, by the minimum necessary so that (a) the result is rectangular once again (b) in the same aspect ratio as before and (c) without any distortion (stretching) of the image.
- Have this rotation+crop adjustment fixed during the entire clip.

After playing around with the skew controls, and cascading Rotation and Crop filters (why are there THREE of them-Crop, Crop and Cropping??) and removing the time variation out of them, and then still not getting what I wanted (manual is no help--too brief), I figured that I'm probably making a simple thing complicated, so I thought I'd pose the question to the forum.

Thanks!
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lata
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Re: Compensating for camera skew

Post by lata »

Hi

Try using the Customise Motion option.

Right click the clip in the timeline and choose Customise Motion.

Rotation and Size should do what you want?

There is also a FX Picture in Picture filter that is quite versatile
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tanguero
Posts: 111
Joined: Sat Jan 03, 2015 4:19 pm
operating_system: Windows 7 Professional
System_Drive: C
32bit or 64bit: 64 Bit
ram: 8GB

Re: Compensating for camera skew

Post by tanguero »

lata wrote: Try using the Customise Motion option.
Right click the clip in the timeline and choose Customise Motion.
Rotation and Size should do what you want?
Thanks, that in fact does the trick! For my problem I needed to set:
Rotation: Z=-8 (since rotation is counter-clockwise by default) -- can also rotate any of the 4 magenta handles to rotate visually.
Size: X=Y=124% (keeping aspect ration locked helps) by trial and error (the yellow size handles for visual adjustment unfortunately don't let you extend to numbers >100%)
Repeat the above for Keyframe 1 (the end-of-clip keyframe) (or rightclick the Keyframe 0 marker and select "Copy and Paste to All")

And it indeed seemed that the PIP filter could probably do the same thing but this was simpler. Thanks again for the quick and complete response!
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