vlc实时转码成mp4v，并使用rtsp组播的命令
vlc 1.mpg :sout=#transcode{vcodec=mp4v,scale=0.4,acodec=mp4a}:rtp{sdp=rtsp://:554/test.sdp} :no-sout-rtp-sap :no-sout-standard-sap :sout-keep
vlc 1.mpg :sout=#transcode{vcodec=mp4v,scale=0.4,acodec=mp4a}:rtp{sdp=rtsp://:554/test.sdp} :no-sout-rtp-sap :no-sout-standard-sap :sout-keep