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Mocha AE corner pin over-scaling
I’m tracking a video into a dolly (in) shot of a tv screen. The track is perfect. I export tracking data as “Corner Pin Motion Blur”, copy it to clipboard, paste it to my new video in AE which has the same specs as the comp. The problem is that the video ends up at around 720% when it reaches full screen. I’ve read that this is an issue that was fixed in Mocha 2.5, but I’m on version 4.0.2.
I understand that corner pin uses scale, so I’ve tried to start my tracking at the point in the dolly shot when the tv screen is at its biggest, but it still scales up the image too much.
Can anyone tell me what I’m missing?
Thank you.
Footage: Shot on A7Sii, 4k 24fps.
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7 Replies
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100% Scale is determined by the last place you adjusted the surface.
If you’ve tweaked the surface somewhere in the shot, mocha will take that position in time as the 100% scale, then scale up and down fro there.
So the solution is to tweak the surface from the largest point.
Martin Brennand | Product Manager | mocha – Imagineer Systems
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OK, so if I track the tv, and it’s a good track, I can still tweak the very last frame in Mocha before exporting the tracking data, and that last frame will be what determines 100% scale in AE? I need that last frame to be 100% (or close).
Thanks!
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Jason, can you show us some screenshots or a video capture demonstrating the problem? You can drag and drop jpgs or copy paste from clipboard right in the text field.
Roei Tzoref
After Effects Artist & Instructor
♫ Ae Blues Tutorials -
Martin’s solution worked! I was a little unsure of how to implement it bc I’m brand new to Mocha, but it ended up being just as he described. The z-space tracking data from Mocha is interpreted by AE’s Corner Pin through the scale parameter, so you have to drop a reference point of sorts (the way Martin described above) before copying/saving in Mocha to tell AE when the target image should be at 100%.
I googled it about 25 times and couldn’t find anything. I can’t imagine I’m the only person to encounter this issue, but maybe it’s not too common.Thanks for all the help guys!
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Glad it worked!
I think what we need to do is add a new parameter in mocha to make this clearer, even if it’s just a “set 100%” button. I’ll write it up as a feature for future versions!
Martin Brennand | Product Manager | mocha – Imagineer Systems
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Cool! That would definitely help clear up confusion for anyone trying it for the first time, and eliminate the need to make an unnecessary adjustment to set a keyframe of sorts.
Thanks again! Our long, single-take from outside a house, through the front door, and into a living room TV screen works! We weren’t sure it could be pulled off.-J
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[Jason Kapell] “The problem is that the video ends up at around 720% when it reaches full screen.”
one way to avoid this scenario, and Martin can correct me if I am wrong here, is to use “corner pin only”, and for the motion blur you could use CC Force Motion blur on top of the corner pin. you will get the same results as MB corner pin and with no downgrading issues due to scaling.
Roei Tzoref
After Effects Artist & Instructor
♫ Ae Blues Tutorials
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