Well, as I lost my database, I could not recover this article, but I still got my script, so here you go:
INRES="1920x1080" OUTRES="1920x1080" FPS="30" QUAL="medium" STREAM_KEY="live_123_xxx" ffmpeg -f x11grab -s "$INRES" -r "$FPS" -i :0.0+0,0 -itsoffset -00:00:01 -f alsa -i hw:3,0 -f alsa -i hw:0,0 -filter_complex amix=inputs=2:duration=first:dropout_transition=3 -af aresample -vcodec libx264 -preset "$QUAL" -s "$OUTRES" -acodec libmp3lame -ar 44100 -threads 6 -b:a 512k -pix_fmt yuv420p -f flv "rtmp://live.justin.tv/app/$STREAM_KEY"
You get your stream key here. Adjust resolutions as needed (input and output), aswell as FPS. In lines 13-16 you can change your audio devices (speakers and microphone, get them from “arecord -l” for microphones and“aplay -l”for speakers). Adjust threads to the amount of CPU cores you want to use to encode.