I have the same problem since this morning. Worked fine last night, but now YouTube and Vodlocker (and a few others I tried) have a stuttering sound, like an FM station that can't stay in place (loud,soft,loud,soft). Thinking my speakers were dead I tried CD+DVD, but they work just fine, also no sound issues with IE and Firefox.
I have Opera version 32.0.1948.25 installed, though I don't know when the latest version was updated, because it's done automatically (so don't know if it was done somewhere between last night and this morning).
I work with Windows Vista (I know, I know, ... deep sigh) but since 2 other browsers work just fine, I do have the feeling it's Opera related.
Afterthought: I did however update DIVX this morning, so maybe it's related to that?
Any ideas, any help would be appreciated...