Convert Video to mp3
Let's all be honest for a moment: we've all ... not paid for ... music. Whether it was via a file sharing app like Kazaa or Napster, or it was downloading and seeding on bittorrent, or maybe even downloading a music video and ripping its audio, we've all pulled some "gangsta shit" to get a track or two. You should only feel ashamed if it was Nickleback. And hey, there are times when you legitimately want to pull audio from a video...though I can't think of any.
If you do want to pull the audio of a video file, for whatever reason, you can do so easily with ffmpeg. Let's use ffmpeg to take a downloaded YouTube video and rip its audio into and MP3:
ffmpeg -i music-video.webm -vn -ar 44100 -ac 2 -ab 192 -f mp3 music.mp3
Using the command above, we take the source video and output its audio to mp3 with a 192kb/s bitrate.
There are in-browser tools and websites you can use to rip audio from YouTube or other video files, but ffmpeg is quick, simple, and hassle free. You can also replace "mp3" with other audio formats if you so choose!
In case anybody is not into command line, there is a UI for this conversion,
https://addons.mozilla.org/en-US/firefox/addon/media-converter-and-muxer/
Thanks for saving my time!
"ffmpeg -i music-video.webm -vn -ar 44100 -ac 2 -ab 192 -f mp3 music.mp3"
above command helped to convert video to audio (Ubuntu machine).