What is CMAF and the implication for HLS

HLS Upgraded with Support for Fragment MP4 Files and More

So far, HLS and DASH have been competitors in the streaming industry, but with the recent developments, HLS has now become compatible with DASH. What does this mean for the industry? What does this mean for the streaming protocols? How will this impact the current and traditional streaming practices? Those are some questions that we will try to answer today.

What Do We Know So Far?

Support for Fmp4:

Apple recently announced its support for fragmented MP4 files. Apple has finally included byte-range addressing for fragmented MP4 files, which means that the file will be playable in HLS without having to multiplex it into the traditional MPEG-2 Transport Stream. This new update will make HLS compatible with the current standard, MPEG-DASH.

This will definitely increase your storage footprint by 2 times, and the CDN efficiency will also be reduced. Furthermore, the converted content will not be reusable across different devices.

Previously, you had to multiplex your content into MPEG-2 Transport Stream, and then you had to multiplex your content into fragment MP4 files in order to be used with the native HTML5 playback. However, with the recent development, you will only have to multiplex your content once, and it will be supported by HLS and MPEG-DASH.

This development and support function was announced at WWDC16. Here’s a snapshot to give you a clear idea of how the HLS m3u8 will look:

If you want to test the support functionality by yourself, you can do that at the official HLS Test Asset released by the Apple developers. There are also some additional guidelines to help you understand the conversion method in a better way.

Here’s the key features when it comes to HLS support for Fmp4 files:

  • HLS content compatible with DASH and vice versa.
  • Encode and multiplex your content once.
  • Use the encoded files with HLS or DASH.
  • Reuse the same content for HLS and DASH to improve the CDN efficiency.
  • Negligible changes in HLS playlists.

DRM Protected Fmp4 Segments:

Simple support for fragment MP4 files isn’t the only thing new with HLS. It now also supports DRM-protected fMP4 segments using MPEG-CENC (Common Encryption). It is supported by all the major browsers, and MPEG-DASH already supports DRM protected Fmp4 files.

Offline Playback:

Users can now persist videos on their respective devices and can view them later on without the need for an active internet connection.

The applications will control the downloadable renditions of the video as well. This way, the application can only download the important media files and audio tracks for the users and save memory in doing so. FairPlay content can now also be played without any connection to the license server.

Here are the key points to give you a better idea:

  • Supports FairPlay streaming with cbcs mode.
  • Syncing the DRM technologies together.
  • Encode the data once and use it with Widevine, PlayReady, PrimeTime and FairPlay.
  • Control downloadable media renditions.
  • Offline playback available for times when you don’t have access to an internet connection.

In-Playlist Timed Metadata:

The new functionalities of HLS also support a new metadata format. It shares some common features with the ID3 tags, but it will not be packaged in the media stream. It will fetch the entire information in advance when you download the manifest, and you can use it for features like navigation control, etc.

If you want to take a cursory look at the new In-playlist timed metadata, here are some key points for you:

  • Similar feature support as ID3 tags.
  • Advanced information control when you download the manifest.
  • Advanced information can be used for navigation, etc.
  • Contains bindings for SCTE-35 tags.

The Bottom Line:

With the new updates, Apple has taken the first step to harmonize the DRM technologies together. The new HLS protocol will also bring together different streaming protocols, reduce storage footprint and allow you to use the same encoded files for different protocols.

This will make it easier for the users to switch from one technology to another. It will surely have a huge impact on the media and the streaming industry. We just have to wait and watch the effects as more and more users start using the new features.

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