The performance boost can be significant, in contrast to having to download every object for each separate movie. Multiple libraries per movie . With this feature, the movie doesn't have to download the whole library before it can start playing. It downloads just what it needs to get going and later downloads other libraries at strategic points as it plays. Streaming audio .
Graphics files are much bigger than sound files.
Therefore, the Flash Player sometimes takes so long to download and display visual content that you hear the crash before you see the tree fall, for example. When you create the composition, sight and sound are in sync. When you preview on a local browser, they're somewhat out of synch. The difference gets worse when you play the composition online. This typically happens when you use a single continuous sound track behind the animation, as opposed to short, isolated sounds that are tied to specific frames.