[teeedubb]

Mpeg2 isn't very CPU intensive so I wouldn't worry about it. I remember I had issues after enabling that setting with vdpau too, but that was a while ago - I think there is something in the wiki about it. Yeah you're bluray rips are most likely x264 or vc1 so disabling that setting won't affect them.

[nickr]

Blurays can be mpeg2 *It's in the spec) but most are h.264. http://www.blu-raystats.com/ tells us that only 5.8% of bluray are mpeg2.