We have a video website(stealth) for which we are planning to add offline play support for iphone, ipad, android and blackberry. Our desktop, in-browser UI works completely on flash. Our videos are all flvs and are streamed to the client side flash UI. These videos are also available as downloadable, offline videos.
Which is the video format/codec(flv? mp4? 3gp?) that has universal support from native video players on all/most of these mobile platforms, both from the point of view of playing it offline and streaming it online. As a last resort, we could always trans-code videos to multiple formats and stream the appropriate one for each of the platforms, but we want to avoid that if possible.