I have placed an mp3 sound in InDesign CS5 and exported to an interactive pdf. In the media panel in InDesign, the sound is playing on page load. When I view the exported pdf in Acrobat X Professional, the sound plays automatically on page load. However, there is a sound icon with a playbar that appears in the pdf. Can I hide this sound icon and just let the sound play automatically?
I've stumbled on this issue and have come up with a really kludgy workaround.
In InDesign I set the poster to none. Then I click the content of the sound frame and make the striped sound element REALLY small. I mean microscopically small. I mean use the control panel to set the size of the element to p0.01 H and W.
Then use the Control panel icon to set frame to content. The sound and its frame will be really small. Hard to see in InDesign.
Now set whatever controls you want for the sound. Play on page load or play with a button or whatever.
The sound will play in the PDF. And still leave the playbar and a black box. But they will be too small to see.
Tip: The reason you shrink the sound element first is so you don't get a message on export that the file is clipped in a way Acrobat can't reproduce and will be adjusted.
I'm thinking that you could do a similar thing for video files that hang around. But they would have to play in a floating window.
All of this is because the Flash Player is now in charge of playing movies and sounds in PDF files.