Ok... I did what you said: mplayer rtp://192.168.1.8:5004 -> almost no delay mplayer -demuxer lavf rtp://192.168.1.8 -> it almost freezes (i think there are about 1 fps or something :) ) ffplay rtp://192.168.1.8:5004 -> errors convert from a pipe to another pipe -> dunno what happens. it just hang.