I'm trying to convert a webm file that has a transparent background to an mp4 file. Mp4 doesn't have transparency so I'm trying to using this color: #D9DADB. How can I make this conversion happen with a single command in ffmpeg?
I've tried the following command and I seem to get a black background instead of a gray one:
ffmpeg -f lavfi -i color=c=0xD9DADB -i 123.webm 123.mp4