i was wondering if its possible to "pause" the buffering activity.

lets say a client have 10MB downstream, and he starts to play a 1GB flv movie, 2 hours duration.
fetching 1GB file with 10MB ability, takes 100 seconds (1 minute, 40 seconds).
i was wondering if its possible to limit the buffer to X seconds overhead.. for example... if the clients play position is 10:00, when the buffer hits 5 minutes inadvance, pause it .. so while he watchs position: 10:00 , buffer will end at: 15:00 ,
while he watch 20:00 , buffer will end at 25:00 ...

is it possible to "pause" it , and continue a request on demand ?

thanks a lot, shai

ps:
even while capping the bandwidth to 1MB, or even 500KB, the result is better, but far from being optimal without limitation of buffer size