Harmy said:

@CatBus: That's interesting. It's definitely true about the noisiness, I noticed it with my BD player, though I don't understand why that is. Can anyone explain? It seems logical to me that if you have the film compressed to fill a disc of the same physical size, the information required to show say one second of the film should take up the same size physical area on the disc, only on DVD it will be less actual information but the rotation speed should then be the same.

I honestly don't know why, but it's not the same physical size. 8GB on a AVCHD is the whole disc. 8GB on a Blu Ray is a narrower band towards the hub, not even the whole disc. My assumption is it's related to data density. On a Blu Ray you can get more data per square inch so to speak, so you don't need to rotate as fast to get the same bitrate. But I don't know that for sure, I'm just thinking out loud.

EDIT: Ah I see what you're saying now. Maybe it's just those magic blue lasers. I have no clue.