If you use Firefox or Chrome and want to “download” a YouTube video in Ubuntu you don’t need to bother installing extensions, addons or 3rd party applications.
- Go to the YouTube page of the video you want to download in Firefox
- Let it load completely (be sure to select HQ/HD if you want best quality)
- Do NOT close the browser OR the page
- Open Nautilus and navigate to /tmp
- Drag the file named “Flash” (followed by letters and numbers) to your desktop and rename it.
- That’s it!
If you use Google Chrome you will find the .flv’s inside your ~./cache/google-chrome/Media Cache folder.
You can play .flv’s in VLC or you can now convert the file to a different format using your preferred method. Handbrake is pretty good!
Thanks to FRUMMAGE @ Ubuntuforums