In the neverending quest for MP4 without licensing woes, there appears to be an (obvious) way to make this happen for 2 more platforms: AIR Windows & Mac, still no way for Flash Player. But dealing with those 2 platforms would mean Flash Player becoming the last platform with mp4 licensing issues.
The answer is – using the native OS Windows / Mac encoders. This would mean leaving ffmpeg for mp4 (goodbye to “crossplatform” internal code for those 2 platforms). But obviously, getting this to work would mean AIR mp4 native encoding, completely free of any royalties or licensing for H.264 / AAC – which is a higher priority than keeping the code comfortable.
So this will become pretty high priority after stabilizing Android.