How to decrease the video latency with flashplayer?

I wrote a flv player with AS and find the video will be buffered in the NetStream for 2.5s when the first frame is decoded. But i set the buffertime is 0.1s. How to decrease the netstream buffertime, especially to reduce the span time between the frameenter time and the decoded time for the first time. 
By the way, the testing based on IE 8 and Flash player 10.3.183.7, the framerate is 25.