$ ffmpeg -loglevel debug -s 1366x768 -f x11grab -i :0.0 -c libx264 -crf 28 -preset ultrafast /tmp/output.mp4 ffmpeg version 3.1.4-1~bpo8+1 Copyright (c) 2000-2016 the FFmpeg developers built with gcc 4.9.2 (Debian 4.9.2-10) configuration: --prefix=/usr --extra-version=...