The Free version of YouTube Downloader will download and convert them to suitable formats for copying to DVD.
My wife uses it all the time to download and save clips of her favourite actors.
Dell XPS 13 9370 (2018) review
No need to scan sketches into your computer with Moleskine's new smart pen
WWDC history: Apple's product launches since 2005
Comment importer des contacts d’un iPhone à un autre iPhone ?