The latest version of Edge Animate was released recently and one of the new features was the ability to save with a transparent poster image. That was a great addition but when I tried to place the OAM file in InDesign and tested it out, I still had a black background.
I did a bit of digging and found out the transparent background only works on PNG and JPG articles. I always use PDF format for folios so rasterizing everything was not something I wanted to do. Then I remembered a post on the User to User forums a while back with a great tip on how to get this working on PDF folios.
When you publish the OAM, be sure to set the poster image to transparent.
After you place it, select the OAM file and then open the layers panel. You’ll see the OAM file there twice. Once as a container (the frame) and once as the content (you may need to click the triangle expand the selection).
Make sure you have the frame selected and open the Effects panel and set the opacity to zero.
Let’s finish it up in the Folio Overlays panel. With the OAM file still selected open that panel and it will automatically show the Web Content pane. Set it to Auto Play with a .125 second delay (this prevents the animation from playing before the page loads). Select “Transparent Background” and deselect “Allow User Interaction” and “Scale Content to Fit.”
The animation will now play with transparent background.
I wish I could find the post to provide the proper credit for this very clever solution.