Preparing Content for Apple iOS Devices
Video creators that want their work to play on Apple iOS devices need to know a little about the H.264 codec and about Baseline and High profiles. For those just starting out, StreamingMedia.com contributor Jan Ozer addressed the subject at the recent HTML5 Video Summit in Los Angeles.
"H.264, the thing that you need to know, it's a wonderful standard. It's adapted by the ITU, the ISO, but if you're here for iOS devices, it's the primary codec used for iOS devices and that's really all you need to know," began Ozer.
So H.264 is the codec needed. But what are these things called "profiles"?
"When you're producing for iOS devices, the critical characteristic you need to know is something called a profile. So what is an H.264 profile? ...It defines a set of coding tools or algorithms that can be used to generate the bitstream," said Ozer.
There are Baseline and High profiles, but Baseline is the one that applies for iOS-supported video.
"The Baseline profile gives you the lowest possible quality, but it's easy to play back. And the High profile gives you the highest possible quality, and it's a little bit harder to play back. Why did the H.264 creators give us profiles? So that people who were producing devices could support H.264 at a more or less limited level. So when Apple decided to build the original iPod, they wanted to support H.264 but they needed to limit the budget for RAM and for CPU power. So they said, 'Okay, we'll support the Baseline profile.' You, as a video producer, if you want to get your video on that device, you know that you need to produce to H.264 using the Baseline profile in your encoding tool. So it's a convenient meeting spot between hardware developers on one side and video producers on the other side," explained Ozer.
For more on encoding for iOS devices, watch the full video below and download Ozer's slide presentation.
How-To: Encoding Video for iDevices
This seminar starts by detailing the playback specs for all iDevices, old and new. Then, it shares the strategies used by prominent iTunes publishers to serve the complete range of installed iDevices. Next, the seminar switches to cellular wireless delivery, with a technical description of Apple's HTTP Live Streaming, including recommendations for the number of streams and Apple's encoding parameters. The seminar concludes with a review of encoding options for HTTP Live Streaming and techniques for serving multiple target platforms such as Flash and iDevices with one set of encoded H.264 files.
Speaker: Jan Ozer, Principal, Doceo Publishing