From Optflux
If you’d rather do without the problem of downloading a particular download facebook videos to download your selected YouTube video, you can always use an online tool. Though there are a lot of web-based download platforms for YouTube, GetanyVideo is our current favorite. It’s neat and fast and won’t maybe you have clicking through pages which spawn popups or another intrusive ads.
1: Discover the YouTube video you wish to download and duplicate its URL from the address bar towards the top of your browser window.
Step 2: Visit the GetanyVideo website.
Step 3: Paste it into the bar that reads “Enter the video's link...”
Step 4: Select your chosen video format and click on the respective blue “Download” button on the right-hand side.