What are some alternatives?
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.
FlashGot - FlashGot is a browser extension for Mozilla Firefox that is designed to make it easy to download a whole batch of files in one go. The extension is open source and free to use, but it is no longer compatible with the most recent version of Firefox.
SaveFrom.net - Free Online service to Download YouTube videos at one click! The best YouTube Downloader supporting fast and easy vimeo, Facebook and Dailymotion video Download and much more!
ClipGrab - vanbittern entwickelt individuelle Weblösungen.
youtube-dl - A small command-line program to download videos from https://alternativeto.
Magic Actions for YouTube - Magic Actions is an extension that changes the way you’ll watch videos on YouTube.