I'm using CS3 and trying to get an flv file closer to 10 megs if I can--currently the file is 14 megs, 640x480, 800mbps, keyframe@30; audio comp @ 96, using the On2 codec. The quality is about as low as I want to go. Is the H264 codec significantly more efficient--can I expect to knock off a few megs with similar settings?
I've avoided upgrading to CS4 but if it will help in this case I will.
H.264 will definitely knock off a few megs and be better quality. You don't need to upgrade to CS4. You just need to an app to compress to H.264. It can even be a QuickTime file. Yes, Flash can play QuickTime movies, they don't have to be flv or f4v. That is unless you need the metadata information in them that Flash can read.