Try spraying some PB Blaster so that it will get in behind the disc and let it sit for a while. Try what is shown in the youtube video. If that doesn't work resort back to the hammer.
My friend's Highlander was like that. There were spots on the disc where you could thread bolts to break the connection but instead it actually tore the metal apart, that's how badly they were rusted on. After letting them all sit for a half hour I was able to get them off using the hammer again. Good luck.