[rtmpdump] mplayer can, but rtmpdump can't

[user]

mplayer rtmp://xxx.xxx.xxx.xxx/media/nintendo/N3DS-PE-low.f4v
-dumpstream -dumpfile out.flv
works fine, but

./rtmpdump -r rtmp://xxx.xxx.xxx.xxx/media/nintendo/N3DS-PE-low.f4v -o
out.flv
RTMPDump v2.3
(c) 2010 Andrej Stepanchuk, Howard Chu, The Flvstreamer Team; license: GPL
Connecting ...
INFO: Connected...
WARNING: Received FLV packet before play()! Ignoring.


XML file with IP : http://p.umcdn.com/ondemand/nintendo/N3DS-PE-low.f4v.xml

player : http://live.nintendo3ds.nintendo-europe.com/