http://www.screencast.com/t/CdVnCpXd Please watch my screencast that will explain my delima I need a step by step for dummies as I just downloaded after effects and got part of the way but now stumpped
This question is asked all the time. I'ts answered in the FAQ and in several tutorials and several columns. Unless you are specifically going to go to Flash you should not use EXPORT ever for anything. Add your composition to the Render Cue and then adjust the output module settings to render to a format that supports alpha channels, set the color to RGB + Alpha and matted to Straight. Render and you'll get a movie that has an alpha channel if you picked a format that supports alpha transparency.
To give you more specific instructions you should tell us what you plan to do with the video. I have no idea and it could be anything. There are dozens if not hundreds of options here so please let us know what you want to do with the video and what the end product will be.
I Have hundreds of videos that are mp4 format and Ideally I'd like to lay this type of transparancy over mp4 video just to used in a video--O may eventually also want to incorperate walking figure in web page shortly after (png or jpg) image file on web page is opened--Thanks
I also do a lot of work in camtasia studio and really would like to have that transparant video also incorperated as an overlay in that program. For still transparancies I use png or gif for movies flv is not an option and of course avi shows the alpha channel as black--I need it transparent.
You'll want to composite your movies either in After Effects or a NLE. Export them as QuickTime with PNG compression or Animation Codec QT or use one of the few AVI's that support transparency. I also do a bunch of Screen Capture movies but I render them to a production codec and edit them either in AE, PPro or FCP, add my overlays and go from there.
Haven't used Camtasia for a long time but the screen cap program I do use fully supports bringing in movies with transparent backgrounds as well as stills.
Neither the Media Player or the QuickTime player will playback videos with alpha channels with a transparent background because the background of the media player is black. Both AVI and QT in the right format fully support alpha channels.