I've tried this but didn't work
Code:
rtmpdump -r "rtmp://89.248.171.90/cast4u/" -a "cast4u/" -f "WIN 24,0,0,221" -W "http://www.cast4u.tv/static/scripts/fplayer.swf" -p "http://www.cast4u.tv/embedplayer/btsp1/1/630/450" -y "btsp1?id=29&pk=80eb0f28ce60258e501b1081624717d4527f7f3fda942e1bff5bf95ae5abe33e" -T "%XB00(nKH@#." -o "BT1.flv"