avconv -i http://admin:""@192.168.1.99:99/Videostream.cgi -b 4000k -s qvga -minrate 4000k -maxrate 4000k -bufsize 1835k -timestamp now -bufsize 1835k -vcodec mjpeg -f flv rtmp://coreserver/live


Here is the Output

avconv version 0.8.6-6:0.8.6-1ubuntu2, Copyright (c) 2000-2013 the Libav developers
  built on Mar 31 2013 01:04:55 with gcc 4.7.2
[ingenient @ 0x39020] Could not find codec parameters (Video: mjpeg)
[ingenient @ 0x39020] Estimating duration from bitrate, this may be inaccurate
http://admin:@192.168.1.99:99/Videostream.cgi: could not find codec parameters