Rotoscope glitches for no apparent reason

[thomas95524452]

Imagine that i'm rotoscoping an airplane in a video of a plane flying through the sky. And i'm overlaying this onto a background video of the solar system.
Even though I have carefully checked every single frame and made sure that the Alpha Boundary is perfectly around the plane, when I export, the .avi sometimes shows quick flashing of frames with a large portion of the blue sky being overlayed too, even though i've checked every single frame and the sky is rotoscoped out.

Has anyone had this problem before? Is it perhaps an encoder problem?

Thank you!

[Szalam · Accepted solution]

Did you use the Roto Brush to do your rotoscoping? If so, did you freeze the Roto Brush when you were done tweaking it?

If you did freeze it or if you didn't use the Roto Brush, we will need the standard set of information.

[thomas95524452]

I used the one on the toolbar at the top. Clicked it, and started brushing my video. I did not freeze it. Could you go into this further? I'm not sure how to freeze it.

Extra info:

System: i7, Nvidia 970, 16gb

Outputting using 'best settings' and 'lossless'.
Source: h264
Version: 13.8

[thomas95524452]

Fixed it! I had to freeze it. I just found the setting now. The output is now perfect. Thank you!
As you can tell, i'm still new to this. Do you mind explaining the benefit? I'm gonna give it a further look now.

[Szalam]

Don't forget to mark the "correct" answer as such to help future forum goers find the right answer more quickly.

The Roto Brush is not as intuitive as it looks, check out the resources on this page; it's a pretty good resource.

[Dave_LaRonde]

If you know how to use Rotobrush, my guess is the source footage itself.  If you had to roto, that means it's a video file,  That video file could be in a highly compressed codec. As I just read, it IS highly-compressed -- H.264.  Ugh.

Despite all of Adobe's protestations to the contrary, I do not trust highly-compressed footage in AE.  I recommend giving yourself the best chance at success in AE by transcoding your footage to something that is NOT highly-compressed.  I go with Quicktime movies in JPEG 2000, PNG, Animation, or Photo JPEG codecs.