[nils@fyps ~]$ ffmpeg -f x11grab -s 1920x1080 -r 24 -i :0.0 -f alsa -i hw:1,0,1 -ac 2 -c:v libx264 -preset fast -pix_fmt yuv420p -s 1024x576 -ar 44100 -threads 0 -f flv "rtmp://live.twitch.tv/app/live_********************************"
ffmpeg version git-2013-02-02-985e93a Copyright (c) 2000-2013 the FFmpeg developers
  built on Feb  2 2013 02:53:55 with gcc 4.7.2 (GCC)
  configuration: --prefix=/usr --enable-gpl --enable-libass --enable-libfaac --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree --enable-x11grab
  libavutil      52. 17.100 / 52. 17.100
  libavcodec     54. 91.100 / 54. 91.100
  libavformat    54. 61.104 / 54. 61.104
  libavdevice    54.  3.103 / 54.  3.103
  libavfilter     3. 35.100 /  3. 35.100
  libswscale      2.  2.100 /  2.  2.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  2.100 / 52.  2.100
[x11grab @ 0x2e0ce80] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 1920 height: 1080
[x11grab @ 0x2e0ce80] shared memory extension found
[x11grab @ 0x2e0ce80] Estimating duration from bitrate, this may be inaccurate
Input #0, x11grab, from ':0.0':
  Duration: N/A, start: 1359779388.075735, bitrate: 1592524 kb/s
    Stream #0:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 1920x1080, 1592524 kb/s, 24 tbr, 1000k tbn, 24 tbc
[alsa @ 0x2e2a860] cannot set sample format 0x10000 2 (Invalid argument)
hw:1,0,1: Input/output error