Record screen in Linux with avconv (replacement for ffmpeg in Ubuntu):
avconv -f alsa -i pulse -f x11grab -r 25 -s 1920×1080 -i :0.0+0,0 -vcodec libx264 -pre:0 lossless_ultrafast -threads 0 video.mkv
Compress video and make ready for YouTube:
avconv -i video.mkv -c:v libx264 outputfile.mp4
Record screen in Linux with ffmpeg:
jonas@erebus:~$ ffmpeg -f x11grab -r 15 -s 1280*800 -i :0.0 -vcodec libx264 -vpre lossless_ultrafast -threads 4 -y -sameq out.mkv
Compress video and make ready for YouTube:
ffmpeg -i video.mkv -vcodec libx264 -vpre hq -crf 22 -threads 0 video.mp4