Last Updated: Nov. 19, 2014

While any HD content looks noticeably better than standard-definition movies or TV shows, there are two levels of HD quality. The iTunes Store hasn't always offered content in HD, but when it started doing so, it only supported the lesser of the two: 720p. Since then, the iTunes Store's HD support has been upgraded to 1080p, but getting that higher-resolution standard isn't the default.

Here's what you need to know about getting 1080p content at iTunes.

The Difference Between 720p and 1080p HD

The two dominant HD standards—720p and 1080p—are both high definition and may be hard to differentiate using the naked eye, but they're not the same. That difference will be most noticeable when watching 720p content on a device that supports 1080p. The picture quality in that case won't be as good as 1080p content on a 1080p device.

The 720p HD standard offers a 1280 x 720-pixel resolution, while the 1080p standard packs in 1920 x 1080 pixels. Needless to say, 1080p images contain more information and more pixels, leading to a more detailed and high-quality image.

It's worth knowing that because 1080p content has 2.25 times as many pixels as 720p content, it takes up more storage space, and will take longer to download. That said, Apple's new compression scheme has allowed it to create 1080p files that are just 1.5 times bigger than 720p files, according to Ars Technica, which means faster downloads and less storage needed than one might expect.

Apple Devices That Support 1080p HD

As noted above, for the first few years of HD support at iTunes, content was only available in 720p. In keeping with that choice, Apple's devices only supported 720p HD content. With the introduction of 1080p at iTunes, that changed. As of this writing, the following Apple devices support 1080p:

• iPhone 6 Plus
• 3rd generation Apple TV (whose only real upgrade over the second-generation model is 1080p support)
• 3rd generation iPad and newer (which sports a 2048 x 1536 Retina Display)

Of course, any 1080p HDTV can also use 1080p content from iTunes.

Downloading 1080p HD Content from iTunes

Since not all Apple devices can play 1080p content yet, Apple gives users a choice of which kind of HD content they'd prefer to download. You don't make this choice at the iTunes Store when you buy or rent movies or TV shows. Instead, you make the choice in the iTunes program itself. To do this:

1. Make sure you're running iTunes 10.6 or higher. If not, download it.
2. Then open Preferences. On a Mac, this is in the iTunes menu. On a PC, it's under Edit.
3. In the Preferences window, click on Store.
4. Look for the option for When downloading High Definition video, prefer: and click the drop-down. Select 1080p.
5. Click OK.

Your iTunes is now set to download 1080p content whenever possible. Though, as that phrasing might indicate, there's one catch.

The One Limitation

Because 1080p support is a relatively new addition to iTunes and the iTunes Store, not all content is available in that format yet. That's why the setting is to prefer 1080p over 720p. With that setting, you'll get 1080p HD content whenever it's available. If it's not, you'll get 720p.

There's no specific warning about that, so you'll need to check out the information for the item you're interested in. To find that, look under its price in the iTunes Store and you'll see what HD formats the item is available in.