screencast | record-audio | record video | noise cancelation
assuming you also want [the sound](ffmpeg-record-audio]
see what’s available
ffmpeg -hide_banner -formats
record as MPEG4
ffmpeg -hide_banner -loglevel info \ -f pulse -i default -ac 1 \ -f x11grab -s 1920x1080 -i :0.0 \ -threads 0 -y output.avi
moar audio options
# -acodec pcm_s16le # -acodec aac
moar video options
# -video_size 1920x1080 # -framerate 25 # -r 30 # -vcodec libx264 -preset ultrafast
moar performance options
# -thread_queue_size 512 # -probesize 10M
https://stackoverflow.com/questions/19828236/how-to-record-audio-with-ffmpeg-on-linux
https://stackoverflow.com/questions/29478548/screen-capture-with-audio-in-ffmpeg ==> FLV trick
https://video.stackexchange.com/questions/15249/screen-capture-and-audio-recording-in-ffmpeg ==> fixed -video_size and -ac