PS3 freezing while watching BDs

[miked924]

In the last few weeks my PS3 has been freezing up while watching BDs...first happened when watching Donnie Brasco a few weeks ago. Everytime I popped the disc out and put it back in it said "This is an invalid disc". So I thought it may be that disc so I tried The Departed (which I watched straight through with no problem when I got it) and it also said invalid disc. I tried Donnie Brasco again the next day and and watched Revenge after it and then there was no problem. Now I'm watching The Fountain and it just keeps freezing. I've been powering down the ps3 and inserting the disc again and even if it does play it won't make it 10 minutes. First time I played it, it froze about 13 min into it. Tried again today and it froze for the first time at 30 min. Other discs won't play either if I try them once the freezing begins on any other disc. I've also never had any issues playing games on it, those never seem to freeze up. This was also happening before I updated to 1.8 so it wasn't that update. The unit doesn't seem any hotter than it usually does but I keep thinking it might be a heat issue. Not sure what else it could be that's causing it, anyone have any ideas?