= FFmpeg video synthesis
{c}
Video with a solid color:
* 2 second white video:
``
ffplay -autoexit -f lavfi -i 'color=white:640x480:d=3,format=rgb24,trim=end=2'
``
Also add some audio:
``
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
``
TODO how to ffplay the video + audio directly? `-map` does not seem to work unfortunately.
* 2 second white followed by 2 second black video:
``
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'
``
* bibliography:
* https://superuser.com/questions/1153930/how-to-generate-a-pure-white-background-video-with-ffmpeg
Display count in seconds on the video:
* black text on white background. Start from 0 and count up to 2:
``
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
"
``
* bibliography:
* https://gist.github.com/derand/31b8312fd64156120cb8f45825a1f0f7
* https://www.reddit.com/r/ffmpeg/comments/11kxugt/make_a_video_timer_or_countdown/