How to download an MP3 track from a YouTube video

Install youtube-dl from the official repository in Ubuntu:

sudo apt-get install youtube-dl

To download a video execute the following:

youtube-dl <url>

E.g

youtube-dl http://www.youtube.com/watch?v=_z-hEyVQDRA

You can also specify other options

-b            Best quality
-m            Mobile version
-d            High Definition
-g            Don’t download, just show the url
-c            Resume download of a video which was interrupted before
-w            Don’t overwrite existing file

For complete list of switches execute man youtube-dl in terminal.

Information from http://www.absolutelytech.com/2010/06/26/howto-download-youtube-video-from-command-line-ubuntu/
Converting to mp3

Now install ffmpeg from the official repo.

sudo apt-get install ffmpeg

Next have a look to make sure the flv file has downloaded from youtube by typing

ls *flv

This will list all the flv files you have. What you should see is a flv file with the same name as the 'v' component of the youtube url you downloaded.

E.g if you downloaded http://www.youtube.com/watch?v=_z-hEyVQDRA then you should have a file called _z-hEyVQDRA.flv

Next you need to copy that file name and then put it in an ffmpg command like

ffmpeg -i <file name>.flv -acodec liblamemp3 <song name>.mp3

So for this example you would type

ffmpeg -i _z-hEyVQDRA.flv -acodec liblamemp3 MasterOfPuppets.mp3

Once this has successfully completed you will now have the mp3 file you were after.

Note For cleanup you may want to type rm _z-hEyVQDRA.flv to get rid of the flv file that you no longer need.



You can also download the mp3 directly from youtube without converting using ffmpeg

youtube-dl --extract-audio --audio-format mp3 <video URL>

Playlist

youtube-dl -cit --max-quality FORMAT --extract-audio --audio-format mp3 http://www.youtube.com/playlist?list=XXXXXXXXXXX

From the online help:

-x, --extract-audio        convert video files to audio-only files (requires
                           ffmpeg or avconv and ffprobe or avprobe)

Bear in mind as well that youtube-dl defaults to using avconv so you should consider specifying either avconv or FFmpeg at the commandline. From the online help:

--prefer-avconv                  Prefer avconv over ffmpeg for running the
                                 postprocessors (default)
--prefer-ffmpeg                  Prefer ffmpeg over avconv for running the
                                 postprocessors

Further options for keeping the original video, adjusting the bitrate or quality of the audio and a few others can be seen by looking at youtube -h.


https://github.com/rg3/youtube-dl