Apple's fMP4 announcement at WWDC a 'significant step' for video encoding standards, Akamai says

Mixed among the more glamorous announcements at Apple's Worldwide Developer Conference last week was one that few outside the online video industry may have paid attention to: The top software and hardware manufacturer said it will add support for fMP4 (fragmented MP4) to its HLS (HTTP live streaming) protocol in iOS 10 as well as tvOS and MacOS. It's a decided move toward standardizing a key aspect of online content delivery.

Akamai applauded the decision by Apple to go with a specific support method, saying it moves the industry closer to stripping away some of the complexity involved in delivering online video.

"fMP4 is the parent of the emerging Common Media Application Format (CMAF), and Apple's plan to support fMP4 brings the industry closer to the single format for OTT distributors and playback support on all consumer electronics devices," said Akamai's Will Law in a blog post on the company's website.

While the OTT industry has shifted significantly toward reducing the number of media protocols used in encoding and delivery, there's still some work to be done.

Akamai's blog post gives more detailed specifics on various media standards and the state of this particular industry segment, but its meaning could be lost on the average OTT viewer. One big benefit of fMP4 is the way it makes adaptive bitrate streaming easier for the provider and reduces issues for the viewer.

Essentially, fragmented MP4 differs from "normal" MP4 in that an fMP4 video can be separated into segments – a concise explanation can be found here. Rather than sending one huge MP4 file to a video player that supports adaptive bitrate and hoping for the best, an fMP4 has defined segments – say, one every 10 seconds – that align across bitrates.

HLS is one of four major adaptive formats used by most of the OTT industry: Smooth, HDS and their pending replacement, DASH, are also in common use.

"Today, HLS specifies the use of TS (transport stream) file containers, while DASH, although allowing TS, almost uniformly uses ISO Base Media File Format (ISOBMFF) in practice, in particular a variant known as the aforementioned fragmented mp4," Law wrote. "The result is that content distributors wanting to reach a HLS and DASH audience must encode and store the same audio and video data twice – once wrapped in TS containers and then again wrapped in ISOBMFF."

That makes caching video less efficient.

The announcement gives weight to the ongoing CMAF initiative, first proposed jointly by Microsoft and Apple.

"Apple's announcement to support fMP4 in HLS under iOS10, macOS and tvOS gives the industry more confidence that CMAF will live up to its billing as the driver of convergence," said Law.

For more:
- see the Akamai blog post
- learn about fragmented MP4

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