youtube-dl
Best and easy way to download an video/audo is to use youtube-dl tool. This tool is available in Homebrew and it works for multiple resources, not only youtube.
Install brew install ffmpeg if you need to extract the audio.
E.g. of this: Descargar Un pais para contarlo
Commands
Download in mp4 format:
youtube-dl -o "test.mp4" --merge-output-format mp4 https://www.rtve.es/alacarta/videos/un-pais-para-escucharlo/pais-para-escucharlo-programa-1/4969918/
Download the mp4 and extract the audio in a mp3 file:
youtube-dl -o "test2.%(ext)s" --merge-output-format mp4 --extract-audio --audio-format mp3 https://www.rtve.es/alacarta/videos/un-pais-para-escucharlo/pais-para-escucharlo-programa-1/4969918/
Download audio for a video
Install brew install ffmpeg
youtube-dl -x --audio-format mp3 https://www.youtube.com/watch?v=7E-cwdnsiow
Download from text file
youtube-dl -a url.txt
Download best/worse audio/video
youtube-dl -f best https://www.youtube.com/watch?v=7E-cwdnsiow
youtube-dl -f bestaudio https://www.youtube.com/watch?v=7E-cwdnsiow
youtube-dl -f worstvideo https://www.youtube.com/watch?v=7E-cwdnsiow
$ youtube-dl -f bestvideo+bestaudio https://www.youtube.com/watch?v=7E-cwdnsiow