Last week, we took a look at the compression being employed by Apple with its new 1080p content on the iTunes Store, a feature that has allowed Apple to increase file sizes by only 15-25% compared to 720p even as the number of pixels have more than doubled. A number of commenters were interested in seeing how 1080p iTunes content compares to Blu-ray, and Ars Technica has now returned with a new analysis looking at the relative quality of those two sources.



Comparison of color and detail in iTunes 1080p (left) and Blu-ray (right) formats

I was surprised to see how close the iTunes 1080p download comes to Blu-ray, considering that it's only a fraction of the file size. And let's be honest: there are lots of Blu-ray titles that look much worse than this iTunes download. But despite an impressive effort by Apple, Blu-ray still reigns king when it comes to image quality. And unlike iTunes titles, BRDs can have uncompressed multi-channel audio, multiple audio language options, and special features.

The report offers a number of blown-up comparison shots, finding that the iTunes Store content generally compares fairly well to Blu-ray content, although it does struggle a bit more with bright highlights, scenes with high detail and noise levels, and dark gradients.



Comparison of dark gradient handling in iTunes 1080p (top) and Blu-ray (bottom)

(Brightness enhanced for clearer demonstration)

Apple's move to 1080p video content in the iTunes Store is part of a significant shift to higher-resolution offerings, pairing the new new content with movie support for iTunes in the Cloud and new 1080p hardware in the new iPad and Apple TV set to debut on Friday.