Using FFmpeg to screen capture in Linux
Often when I screen capture using kazam or gtk recordmydesktop video replays at a faster frame rate than the audio.
Taking some advice from Matthew Moore's video at • Video
He goes into much more detail if what I used doesn't work for your system
I used the following command in the terminal for ffmpeg
ffmpeg -f pulse -ac 2 -i default -f x11grab -s $(xwininfo -root | grep 'geometry' | awk '{print $2;}') -s 1366x768 -i :0.0 -threads 0 output.mkv
I used the following command in the terminal for mplayer
mplayer -tv driver=v4l2:width=240:height=120: -vo xv tv:// -geometry "99%:95%" -ontop