I saw in a tutorial a discussion on using video with an alpha channel in After Effects relative to the way that the movie is exported. I have a video of a little flying cartoon dragon that I purchased from IStock. In the footage he just flaps his wings. I want to move him toward my model, who makes eye contact with the dragon, and then have things happen to the dragon via After Effects special effects. Then I need to export the movie out to be used on a website. I heard that the H-264 codec was really good for the web but doesn't support alpha channels. So I have two questions:
1. If I am going to precompose everything anyway, then make a movie using the H264 codec, does it matter that 264 doesn't support alpha channels?
2. My tendency is to output this to a swf. How would you recommend I utilized the dragon with an alpha channel, unfortunately at the back end of the footage, and then what settings do you recommend for best use on the web?
From what I understand you will export a final piece for the web, thus it does not matter if the final format supports alpha channels (unless you want your animation to overlap some other stuff on a website). Best format for web video- I prefer .f4v or.flv. Render out from AE in a lossless format (QT Animation mov)then use Adobe Media Encoder to compress.