i am wondering what the best way to export an animation with an alpha channel is if i'm trying to keep the size down as much as possible. Normally when i export with alpha channel i use the "Animation" codec which seems to be bigger because its uncompressed. it needs to be 1080p30. so i guess i'm asking for export settings and codec settings.
i am using after effects cs3 on a mac pro os 10.4.9
Re: small file size for alpha channel graphics by david bogie on Feb 13, 2008 at 5:11:07 pm
In the olden days, we used to export a color movie and an alpha-only monochrome movie. The monochrome was used to feed the track matte feature in another application. the codecs for these two movies could be anything.
bogiesan
This is my standard sigfile so do not take it personally: "For crying out loud, read the freakin' manual."
Re: small file size for alpha channel graphics by Darby Edelen on Feb 13, 2008 at 6:56:57 pm
[david bogie]"In the olden days, we used to export a color movie and an alpha-only monochrome movie."
As an addendum to that thought, the Animation codec at 100% quality is lossless but it is not uncompressed. It uses a form of run line encoding to significantly compress areas of solid color without losing any data. Since alpha channels are generally large areas of black or white (unless you're dealing with an alpha of a snow storm, yikes!) you can generally get very decent compression of just an alpha channel from the Animation codec at 100% quality.
Darby Edelen Designer Left Coast Digital Santa Cruz, CA
