Improved H.264 Compression Holds Down File Sizes on 1080p iTunes Store Content

Ars Technica takes a look at the new 1080p content available on the iTunes Store, showing how a "High" compression profile for H.264-encoded content on the iPhone 4S and new iPad and Apple TV are minimizing the increase in file size needed to move from 720p to 1080p.

itunes 720p 1080p comparison
Comparison of 720p (left) and 1080p (right) video quality in iTunes Store content

In a survey of several titles now available in 1080p on the iTunes Store, the report found that file sizes generally increased by 15-25% over their respective 720p versions, despite the number of pixels more than doubling to reach the higher standard.

The reason that the 1080p versions of the iTunes Store videos can be a good deal better without doubling the file size—or worse—can be found in the tech specs of the new AppleTV and the new iPad. The AppleTV now supports H.264 compression for 1920x1080 resolution video at 30 frames per second using High or Main Profile up to level 4.0, the iPad and the iPhone 4S the same up to level 4.1. The profile indicates what kind of decompression algorithms the H.264 decoder has on board—the "High" profile obviously has some tricks up its sleeve that the "Main" or "Baseline" profiles known to previous devices don't support. The level value indicates how many blocks or bits per second a device can handle.

The report also offers a comparison of video quality between the 720p and 1080p formats on the iTunes Store, noting that the increase in image quality for 1080p content is minor in many cases, but more significant in brighter scenes.

Popular Stories

iPhone 17 Pro 34ths Perspective

iPhone 17 Pro Launching Later This Year With These 10 New Features

Sunday March 23, 2025 10:00 am PDT by
While the iPhone 17 Pro and iPhone 17 Pro Max are not expected to launch until September, there are already plenty of rumors about the devices. Below, we recap key changes rumored for the iPhone 17 Pro models as of March 2025: Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and iPhone 16 Pro models have a titanium frame, and the iPhone ...
iOS 18

iOS 18.4 Expected Next Week - Here Are the Release Notes

Friday March 28, 2025 2:01 pm PDT by
With the second release candidate of iOS 18.4 that Apple seeded out today, the company finally provided us with release notes that give a full rundown on what to expect. There's an Apple Vision Pro app, new Apple Intelligence features for notifications and additional language support, plus an Apple News Food feature for Apple News+ subscribers, and several updates that should improve the...
Magic Mouse Green

What to Expect From the Magic Mouse 3

Saturday March 29, 2025 10:15 am PDT by
Apple is reportedly working on a new Magic Mouse. Below, we recap what to expect. The two key rumors for the Magic Mouse 3 so far include a relocated charging port, along with a more ergonomic design. It was briefly rumored that the Magic Mouse 3 would also feature voice control, but that was misinterpreted information. Relocated Charging Port While the Magic Mouse switched from...
Foldable iPhone 2023 Feature Homescreen

Six Things to Know About Apple's Upcoming Foldable iPhone

Friday March 28, 2025 3:54 pm PDT by
We've been hearing rumors about a foldable iPhone for almost a decade now, but it looks like we might finally see the device come to fruition in 2026. We're going to be waiting many more months for the foldable iPhone, but so far we're hearing good things. Apple wants to make it creaseless. It's taken Apple multiple years to design a foldable iPhone that it's satisfied with because Apple ...
top stories 2025 03 29

Top Stories: WWDC 2025 Announced, iPhone 17 Pro and iOS 19 Rumors, and More

Saturday March 29, 2025 6:00 am PDT by
Apple's big developer event is a little over two months away, and rumors about what we can expect to see in Apple's next major operating system updates are becoming increasingly frequent. A public release of iOS 18.4 is also imminent with a number of updates and improvements, although we won't be getting the major Apple Intelligence Siri upgrades that had reportedly been planned for this...
iOS 19 visionOS UI Elements

Apple Codename Provides Clue About iOS 19's Rumored New Design

Sunday March 30, 2025 6:40 am PDT by
Multiple sources have claimed that iOS 19 will introduce a new design with more translucent buttons, menus, notification banners, and more, and there is now another clue that points towards this glass-like appearance. Bloomberg's Mark Gurman today said the new design project is codenamed "Solarium" internally. A solarium is a room with glass walls that allow in plenty of sunlight, so this...
Facebook Feature

Facebook's New iPhone App Feature Turns the Clock Back to 2007

Thursday March 27, 2025 1:59 pm PDT by
In the mid-to-late 2000s, Facebook was all about staying connected with friends and family. However, as the social media platform added new features and grew over time, that core experience began to get drowned out. That changes starting now, according to Meta, which today introduced a new feature that will "bring back the joy" of classic Facebook. Specifically, Meta has redesigned the...
Foldable iPhone 2023 Feature Homescreen

iPhone Foldable Display Said to Feature iPad-Style 4:3 Aspect Ratio

Friday March 28, 2025 3:44 am PDT by
Apple's upcoming "iPhone Fold" will feature a foldable screen with a 4:3 aspect ratio, according to a Chinese leaker who previously leaked the book-style device's display dimensions. The Weibo-based account Digital Chat Station claims that Apple will adopt a "roughly" 4:3 aspect ratio on the inner display in order to achieve consistency between the outer display, as well as to ensure parity...

Top Rated Comments

studentmac Avatar
170 months ago
Howaaaarrrd!!!
Score: 34 Votes (Like | Disagree)
theMaccer Avatar
170 months ago
Pic of Penny would be much better.
Score: 18 Votes (Like | Disagree)
SB27 Avatar
170 months ago
The Hidden Side of Apple Value

The press mainly focuses on the hardware, sales figures, etc. What people miss about the value that Apple is delivering to customers can be found in this story. At every turn and in every nook and cranny of the Apple ecosytem, their engineers are finding ways to deliver better bang for the buck. Video compression is just one of thousands of ways that Apple thinks completely differently about the user experience than anyone else. This is why they are a $500B company.

I was also struck while watching the keynote for the iPad by the amount of energy and focus put into iLife and iWork. That stuff is simply amazing for only $4.99 a copy (and with mostly free upgrades).

Yes, we are trapped in a closed Apple ecosytem. I like to think of myself as "happily trapped" given the sheer amount of energy, dollars, focus and excellence being delivered in every aspect of their ecosystem.

I will put the pom-poms down now, but this story prompted a visceral reaction and I felt it was worth noting.
Score: 17 Votes (Like | Disagree)
Mr. Retrofire Avatar
170 months ago
At every turn and in every nook and cranny of the Apple ecosytem, their engineers are finding ways to deliver better bang for the buck. Video compression is just one of thousands of ways that Apple thinks completely differently about the user experience than anyone else.
Not really. Apple use(d) their own H.264-encoder, which produces larger files with worse quality, compared to the open source x264-encoder (the command line version). The picture below shows how efficient the x264-encoder is (just an example):



They should work together with the x264-developers (http://www.videolan.org/developers/x264.html). They know the best settings and encoding strategies [1]. x264 is the H.264-encoder with the best visual quality. Warner Brothers use the x264-encoder to encode commercial BDs.

More info:
Seventh MPEG-4 AVC/H.264 Video Codecs Comparison (http://compression.ru/video/codec_comparison/h264_2011/)

Btw:
Apples uses still BZIP2 and ZLIB, which use 10-20 year old compression algorithms (BWT & deflate), to compress the file system, disk images, installer packages, software downloads (Mac App Store), software updates and so on. The newer LZMA and LZMA2 algorithms are not only faster (decompression), the resulting files require also 30 percent less disk space (faster file transfers (downloads)). Apple does not like & use good compression algorithms.


[1]
http://doom9.org/
http://doom10.org/
http://mewiki.project357.com/wiki/X264_Settings
Score: 9 Votes (Like | Disagree)
Deadman64 Avatar
170 months ago
I downloaded 1080P versions of my movies from iTunes and played them on my system (have a 1st gen aTV with a Crystal HD card for 1080P/DTS content on my 60" Pioneer Elite). Truthfully, I saw little difference between the 1080P and 720P iTunes versions, yet a major difference between my 1080P handbraked encodes and direct Blu-Ray movies.

I think that would be a good comparison.

1080P iTunes/Apple TV vs. a 1080P Blu-Ray.
Score: 9 Votes (Like | Disagree)
luke.mac1 Avatar
170 months ago
noting that the increase in image quality for 1080p content is minor in many cases, but more significant in brighter scenes.

So what they're saying is that the difference between 720p and 1080p in the iTunes store is almost negligible? I mean you can see the difference there on the scaled up image, but I imagine you can't really see it on a small screen. Maybe it will be better on a 27" imac or 50" HDTV.
I still think they should offer a larger, higher quality file size for people who wish to download it... maybe something to select in the preferences section of iTunes...
Score: 8 Votes (Like | Disagree)