AWS Media Blog

Enabling CMAF for Video Processing and Delivery

The benefits of using HEVC / H.265 for video content, with its quality improvements and compression efficiency gains compared to AVC / H.264, are well understood. At its 2017 Worldwide Developers Conference, Apple announced that its desktop, mobile platforms and all future hardware will support HEVC content. Apple had already revealed in 2016 the addition of fragmented MP4 (fMP4) support to HTTP Live Streaming (HLS), a format that historically supported only TS (transport stream) file containers. Adding fMP4 to HLS takes an important step towards consolidating the streaming formats used for over-the-top (OTT) video distribution.

Separately, a new media file format in the process of standardization is the Common Media Application Format, or CMAF, which incorporates fMP4 along with other media technologies. The combination of these developments signals the migration from AVC to HEVC and the convergence to a single file format that supports the vast ecosystem of video devices. Because of this, CMAF is widely expected to become the standard for OTT, greatly simplifying the lives of video providers while assuring consistently high-quality streaming experiences for viewers.

AWS Elemental is implementing CMAF support across on-premises and cloud-based video solutions. In April, AWS Elemental MediaPackage added support for CMAF HLS endpoints. And in June, AWS Elemental MediaConvert added support for CMAF outputs using both DASH and HLS endpoints. CMAF support is in development for other AWS Elemental Media Services as well as appliance-based solutions; in fact, the company showcased an end-to-end solution for HEVC, fMP4, and CMAF (for both HLS and DASH clients) in conjunction with just-in-time packaging and delivery for the first time at the 2018 NAB Show.

With CMAF support, AWS Elemental video solutions can create a single file format for live or on-demand streams using either the AVC or HEVC codec along with fMP4 segments. These segments are then delivered as different adaptive streaming technologies using separate manifest files. Because major players (Google with Widevine, Microsoft with PlayReady, and Apple with Fairplay) have all moved to support Common Encryption that is interoperable with CMAF, video solutions from AWS Elemental can also create a single encrypted file compliant with a variety of concurrent digital rights management (DRM) standards. This eliminates the need for separate content silos to support each type of consumer device. Together, these new capabilities offer substantial benefits to video providers by eliminating the cost and complexity of packaging and storing multiple versions of streaming protocols and DRM files on the origin server. And, by removing the need to generate multiple file formats, CMAF can dramatically reduce encoding costs.

Another benefit is content caching efficiency in the network when delivering content. CMAF support limits the overall packaging load of a video workflow that is also applying just-in-time technology to support older devices. CMAF-compliant devices require only lightweight manifest packaging and can use more shared video fragments in caches and content delivery networks, which helps to drive down OTT latency and further improve distribution costs and performance.

Closed captioning for multiple languages presents another challenge for video providers, with different standards being supported by different streaming technologies. CMAF functionality simplifies closed caption delivery by supporting the various standards used by different streaming technologies. Again, this promises significant cost savings for video providers.

In summary, fMP4 and CMAF implementation is future-proofing video delivery through an ‘encode, package, encrypt, and cache once’ approach that supports a variety of consumer devices. AWS Elemental is working with several video providers to deploy CMAF in 2018, to spearhead support for this technology for both on-premises and cloud-based video workflows.

Want to learn more about CMAF? This e-book explains HEVC and CMAF, and ways to incorporate them into your video encoding and distribution pipelines and retain the broadest possible compatibility with your customers.

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James McIntyre

James McIntyre