Searched quite a bit on the net for this but haven't found any discussions on it. Many of the YouTube 1080p vids are much sharper and detailed than iTunes 1080p movies. I was surprised when I downloaded my first iTunes movie last night at 1080p. I expected at least as good as the YouTube trailers. Even my Blu-ray disks played on the computer are at first glance on par with iTunes but fall well short of the YouTube 1080p. Why is this, and has this been the experience of others?