It is possible to stream a live event with red5 to different groups of people who have different internet connections with different speeds, for example for a person on dial up to stream to this person a high quality is useless because he will only see buffering, and little of the real video. Using multi bitrate it is possible to stream for dial ups, or high quality.
this is done on the fmle encoder, select more then 1 stream choose the bitrate you want to use and then on the stream name separate the stream names with a semicolon, for example:
then create 3 different players, if on strobe on the video source use:
RTMP + Stream name
this way you will have 3 players for 3 different group of viewers. More can be read at red5 hosting.