I find ads inside Internet videos really annoying. As consumers of the media we are subject to the whim of the media presenter, since they package the software to play the media along with the media itself. So if they want an ad in our way, they just put it there.
I typically find this very annoying, but I have found a compromise today. Make the video widescreen. That's a simple fix because it creates unused regions in a standard player screen where ads can go. If the ad isn't standing between me and my video, well... I really don't mind it being there at all.