Live screencasting with ffmpeg, ffserver

Put this ffserver.conf file on your server:

 Port 8090  
 RTSPPort 5554  
 BindAddress 0.0.0.0  
 MaxHTTPConnections 500  
 MaxClients 200  
 # 8 Mbits  
 MaxBandwidth 8000  
 CustomLog -  
 NoDaemon  
 <Feed screencast.ffm>  
     File /tmp/screencast.ffm  
     FileMaxSize 30M  
     ACL allow 0.0.0.0 255.255.255.255  
 </Feed>  
 <Stream screencast.swf>  
  Feed screencast.ffm  
  Format swf  
  VideoCodec flv  
  VideoFrameRate 20  
  VideoBufferSize 80000  
  VideoBitRate 768  
  VideoQMin 1  
  VideoQMax 5  
  VideoSize 1376x768  
  PreRoll 0  
  StartSendOnKey  
  AudioBitRate 64  
  AudioChannels 2  
  AudioSampleRate 44100  
  AVOptionAudio flags +global_header  
 </Stream>  
 <Stream status.html>  
     Format status  
     ACL allow localhost  
     ACL allow 192.168.0.0 192.168.255.255  
 </Stream>  
 <Redirect index.html>  
     URL http://www.ffmpeg.org/  
 </Redirect>  

here's a shortcut screencast.sh file, run this on your desktop machine you're screencasting from:

 #!/bin/sh  
 ffmpeg -f x11grab -r 25 -s wxga -i :0.0 -f alsa -ac 2 -ar 44100 \  
  -i hw:PCH,0,0 http://server:8090/screencast.ffm  

Now, simply log on to your server, run ffserver -f ffserver.conf. Then run screencast.sh from your desktop.

You might need to change the input device, you can list them with arecord -l.
Also, replace 'server' with your server address, and check the input dimensions (-s wxga above) and the output dimensions (VideoSize in ffserver.conf) it's a bit tricky and doesn't match the input size to 100%, because the VideoSize dimensions need to be a multiple of 16.