Thread: How Video On Demand Works (long and technical!)
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Old 12-01-2005, 16:38   #23
Tristan
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Re: How Video On Demand Works (long and technical!)
Quote:
Originally Posted by wir3d
When a movie is loaded on to a VOD server for the first time, "trick-play" files are generated. One is just an MPEG of your movie being played fast-forward at 6-7x speed, and another is an MPEG of your movie going backwards. These files, and the main movie file, are all cross-indexed together with respect to time.

When you REW or FF, the server stops playing out the main movie, and switches to playing out the appropriate trick play file, from the appropriate index point.

This saves a huge amount of CPU load on the server, freeing up more capacity for normal playback: generating the FF/REW image on the fly is a fairly expensive process.
I was told about this after I posted the big long thing above. Decided not to include it as I couldn't think of a way to put it consisely, but you've done a grand job there
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