Youtube-dl
There's also a GUI wrapper for it: <a href="https://github.com/MrS0m30n3/youtube-dl-gui/" rel="nofollow">https://github.com/MrS0m30n3/youtube-dl-gui/</a><p>And a php web app that uses youtube-dl as a a backend: <a href="https://github.com/Rudloff/alltube/" rel="nofollow">https://github.com/Rudloff/alltube/</a>