An alternative to youtube-dl has been described here: New Command Line YouTube Player And Downloader With Local Playlists Support: mps-youtube. The article is quite detailed but just to quote what seems relevant to your question:

mps-youtube is a new tool which, besides being able to download YouTube videos (either the whole video or just the audio), can also search and play YouTube videos and create local playlists, all from the command line.

By default, this is basically a YouTube audio player (and downloader), but you can enable (external) video playback from its options.

This program needs the presence of python-pip and mplayer (both of which installable by apt-get). Then, run sudo pip install mps-youtube and you're done.

You can read more about mps-youtube here.

Notes

this program downloads just the audio if you so wish and hence you save on bandwidth: instead of downloading a video and then extracting the audio at your end, you download just the audio.

if you don't wish to install all the recommends suggested by sudo apt-get install python-pip use sudo apt-get install --no-install-recommends python-pip. That works just as well (for the specific purpose of installing mps-youtube).