I use, on a Mac, a tool called "YTD" (YouTube Downloader). Be careful where you download it from thought, I had a version of this install some spamware once ... luckily it was the kind that I know how to remove on a Mac.

I don't have/know the exact "correct" site at the moment (I'm away from my computer)

Jim
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Genos / Tyros5 / HK Lucas Nano 600 / FTB Maxx 40a / EV ZX1A / Rock'n'Roller cart / Hauptwerk virtual pipe organ / misc other audio & music toys