Programming With QuickTime VR
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All of the discussion so far is sufficient to allow you to create a valid QuickTime VR movie. However, there are special considerations when the movie is to be played back on the Internet. Originally, both QuickTime movies and QuickTime VR movies had to be completely downloaded to the user's local hard disk before they could be viewed. Starting with QuickTime 2.5, if the movie data is properly laid out in the file, standard linear QuickTime movies can be viewed almost immediately. The frames that have been downloaded so far are shown while subsequent frames continue to be downloaded.
The important change that took place to allow this to happen was for QuickTime to place global movie information at the beginning of the file. Originally it was at the end of the file. After that, the frame data simply needs to be in order in the file. Similarly, QuickTime VR files also need to be laid out in a certain manner in order to get some sort of quick feedback when viewing on the Web. Roughly speaking this involves writing out all of the media samples in the file in a particular order. Apple now provides a movie export component that does this for you: the QTVR Flattener.
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