This is a tricky one to solve, a lot depends on footage but you can try turning up the Frequency and/or Smooth Colors (although this does blur the result somewhat) parameter.
The best way to do this is to make a black & white mask of where you want the sparkles to appear. Then place this on the video track below the sparkles and in the effect editor for Sparkles set the Mask:1 Track Below and Background: Two Tracks Below.
Sapphire has several different plug-ins you can use. RackDefocus will simulate a camera defocus, while ZDefocus takes a depth buffer to due a depth-of-field defocus. Aharon is referring to our Convolve plug-in which allows you to input a black & white Kernal as your lens shape for a custom lens defocus. You can download a free 3 week trial from:
We are working on a release of FXPlug for Motion and FCP and it will be a free upgrade to anyone who has bought or buys our V2 package for AE & compatible product.
This is an issue where Avid doesn’t properly render the alpha in multiple effects. The solution is to render the topmost effect (S_Layer) on V3 to have this work properly.