This one is working fine for me. ->
Code:
rtmpdump -r "rtmp://198.100.149.81/live/espn" -a "live/espn" -f "WIN 11,6,602,171" -W "http://livecupbrazil.com/player/player.swf" -p "http://livecupbrazil.com/sports.php?n=espn&ckattempt=2" -y "espn.video" -o espn.video.flv