Some cars, like mine, have a video player that can only play specific DivX videos (a.k.a. old format). It doesn’t play YouTube videos.
Of course it is illegal to easily download YouTube videos using yt-dlp, you need to pay premium and watch in their proprietary app or website. Even when you download it, what you get is the cryptic webm format that is not easily playable.
It is possible though, to convert the video you have downloaded to such DivX format using this command (original source here and here):
ffmpeg -i input-file.webm -c:v mpeg4 -q:v 5 -tag:v DIVX -s 640x480 -c:a libmp3lame -q:a 5 -ac 2 -ar 44100 -filter:v fps=25 output-file.aviOr, if you don’t care about DivX format, it is also possible to convert to the usual mp4 format:
ffmpeg -i input-file.webm output-file.mp4Therefore, if you did the things I explained above, you may break the law in your country. You have been warned.