ffmpeg screencast for macos

ffscast.sh

# there's a bunch of things that don't work properly:
# - can't capture computer audio output - it desyncs
# - need to change the input devices (`-i "v:a"`) based on the output of `ffmpeg -f avfoundation -list_devices true -i ""`

ffmpeg \
    -thread_queue_size 150 -f avfoundation -probesize 50M -framerate 30 -pix_fmt uyvy422 -i "2:3" \
    -thread_queue_size 150 -f avfoundation -probesize 50M -framerate 30 -pix_fmt uyvy422 -capture_cursor 1 -capture_mouse_clicks 1 -i "4" \
    -filter_complex '
        [1]fps=fps=30[scr],
        [scr]scale=-1:1440[scr],
        
        [0]fps=fps=30[cam],
        [cam]crop=ih/1.6180339887:ih[cam],
        [cam]scale=-1:1440[cam],
        
        [scr][cam]hstack[vout],

        [0:a]afftdn[aout]
    ' \
    -map '[vout]' -c:v hevc_videotoolbox -b:v 5000k \
    -map '[aout]' -c:a libopus -b:a 256k \
    -y output.mkv