I'm working on a book to be an epub. The epub version works perfectly (sound/animation), then I had to make another version for the publish online. The problem was, when convert to publish online directly, sound was going on way before it's page, for example, on the first page we were hearing the next 4 pages almost at the same time. I solved this problem by inserting play/pause buttons for the sounds. It was working perfectly fine last week, and now this week, some pages don't play sound at all. But in the epub preview in InDesign, everything is working perfectly fine.