A few specific details will help us understand how you did this and thus maybe enable us to give some solutions. When you're in a project, you know all details and you just want to solve the things that do not work, but remember we are not mind readers, remote viewers or AE diviners... so we have no idea how you set up your project unless you tell us.
So- did you track the star corners and link the flare to that data or did you animate by hand?
Is the footage progressive or interlaced?
Any other details that may clarify the way you worked...
What version of AE do you run? If it isn't AE 10, aka AE CS5, you'll probably experience big problems with footage shot on any kind of HDV camera. Not when previewing, but when rendering:
Dave's Stock Answer #1:
If the footage you imported into AE is any kind of the following -- footage in an HDV acquisition codec, MPEG1, MPEG2, AVCHD, mp4, mts, m2t, H.261 or H.264 -- you need to convert it to a different codec.
These kinds of footage use temporal, or interframe compression. They have keyframes at regular intervals, containing complete frame information. However, the frames in between do NOT have complete information. Interframe codecs toss out duplicated information.
In order to maintain peak rendering efficiency, AE needs complete information for each and every frame. But because these kinds of footage contain only partial information, AE freaks out, resulting in a wide variety of problems.
I'm a Mac guy, so I like to convert to Quicktime movies in the Animation or PNG codecs; both are lossless. I'll use Apple's Compressor, Adobe Media Encoder or Quicktime Pro to do it.
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
I understand AE uncompresses any footage you import into it, so it should not matter the footage type. especially since this flare is not part of the image it is generated in AE and all looks fine with the exeption the movement of the lens flare.