 FFmpeg video synthesis

ffplay -autoexit -f lavfi -i 'color=white:640x480:d=3,format=rgb24,trim=end=2'

ffmpeg -lavfi "color=white:640x480:d=3,format=rgb24,trim=end=2[v];sine=f=1000:d=2[a]" -map '[a]' -map '[v]' out.mkv

ffplay -autoexit -f lavfi -i 'color=white:640x480:d=3,format=rgb24,trim=end=2[a];color=black:640x480:d=3,format=rgb24,trim=end=2[b];[a][b]concat=n=2:v=1:a=0'

ffplay -autoexit -f lavfi -i "
color=white:480x480:d=3,
format=rgb24,
drawtext=
  fontcolor=black:
  fontsize=600:
  text='%{eif\:t\:d}':
  x=(w-text_w)/2:
  y=(h-text_h)/2
"