

If you play the clip again, then the player can present the content once more without downloading again: the player uses the file in cache that time.

These clips normally are complete files when finished and normally do end up in the cache. Then there is semi-streaming, which can start playing before the file is completely downloaded.

This streaming video normally won't end up in a cache. This in turn means that what you receive may not be complete: sometimes a few frames may be missing due to arriving too late, and the player just skips these. means serving as many frames as the bandwidth allows up to the captured maximum.
