Customers can enjoy the iTunes films in HD on their Mac or PC and on their widescreen TV with Apple TV, as well as in standard definition on their iPhone or iPod with video. Which is very convenient. However, HD at iTunes isn't what I consider full HD quality -- which would be 1080p. iTunes is 720p, which is good, but not the very best. The best is what you get with Blu-ray.
Admittedly, movies from iTunes don't take up shelf space and more and more things are going digital. High def movies on iTunes also come with a "standard" version for viewing on iPods and iPhones, as well. On the other hand, they do take up LOTS of hard drive space.
But it's quality I'm discussing here. The iTunes 720p resolution is, technically, a higher resolution than DVD, and technically, yup, that's HD. However, as noted by Gizmodo, like every other video download service touting HD videos, it's all actually lower quality than DVD.
As explained by Gizmodo, regular DVD runs at about 6-8 megabits per second. High-def iTunes content, despite having a higher resolution, is half that: 4Mbps. And Blu-ray is 40Mbps.
Then there's audio quality. A compressed Dolby Digital 5.1 soundtrack running at a low bitrate simply doesn't compare to the lossless soundtrack of a Blu-ray disc. The sound is much muddier and murkier.
The iTunes 720p resolution is, technically, a higher resolution than DVD, and technically, yup, that's HD. However, as noted by Gizmodo, like every other video download service touting HD videos, it's all actually lower quality than DVD.
As explained by Gizmodo, regular DVD runs at about 6-8 megabits per second. High-def iTunes content, despite having a higher resolution, is half that: 4Mbps. And Blu-ray is 40Mbps.
Then there's audio quality. A compressed Dolby Digital 5.1 soundtrack running at a low bitrate simply doesn't compare to the lossless soundtrack of a Blu-ray disc. The sound is much muddier and murkier.
And don't look for 1080p iTunes downloads any time in the near future because this positively eats up bandwidth. A standard 720p file downloaded either through iTunes or an Apple TV consumes about 4Mbps of data. That's a tenth the total bit transfer rate of the optical format and a fifth of the nearly 20Mbps for over-the-air HDTV.

In a perfect world, I'd be able to mix and match. Movies that don't benefit from the very highest definition (such as, say, most romantic comedies -- and, no, I don't mean that as an insult) I could buy at iTunes. But the films that really shine in 1080p (say the new Star Trek movie) I could buy on Blu-ray -- and watch on my Mac when I wanted. IF Mac OS X had Blu-ray support.
