When there is a binary available for macOS, this can be installed manually via the command line of macOS. Here is how it’s done.

Youtube-dl can use FFmpeg to convert and merge videos after download. But when you do not want to install ffmpeg via homebrew or macports, there is a binary of ffmpeg available under https://evermeet.cx/ffmpeg (found via the official website of ffmpeg).

1. Privileges

Maybe you need to know how to switch the roles in the terminal:

sudo -s admin lets you switch to the admin account, and with

sudo -s you switch to root.

2. Download binaries

Check out https://evermeet.cx/ffmpeg and download the archived binary (i used the release, not the snapshot).

3. Install on system

Move the extracted binary to the local bin path:

mv ffmpeg /usr/local/bin/

And done, youtube-dl should now find ffmpeg and work flawlessly :)