This will avoid the need for OTT video providers to generate and publish separate metadata for the proprietary APIs of every CDN vendor that they might traverse in their delivery chain. The two companies aim to deliver the CDN configuration metadata standards through a Streaming Video Alliance’s (SVA) technical specifications document that will serve as the streaming industry’s guide, due for completion by the end of 2022.

This will benefit not just streamers, but many online content providers, which will be able to adopt a common metadata model and single API to publish CDN configurations to all vendors. Currently, such organisations have to model and publish metadata separately within each CDN vendor’s proprietary API or management portal, which becomes cumbersome and expensive for publishers that distribute their content over multiple streaming networks.

“We believe all streaming providers will benefit from standardisation across commercial CDN providers and the Open Cache industry, which is why we’ve led the charge, working alongside companies like Lumen, on evangelising this important work,” said Michael Fay, vice president, software engineering, Disney Streaming. “Hundreds of millions of subscribers already engage with Disney+, Hulu, ESPN+ and Star+, and as demand increases for our direct-to-consumer platforms, we believe standardization will be a key driver in maintaining our reputation for delivering a high-quality viewing experience for subscribers at scale.”

Open caching has been developed to reduce the burden on internet service providers (ISPs) imposed by rapid proliferation of on demand video traffic over their networks, by allowing it to be stored locally and then delivered as required to users nearby. But the ability to overlay delivery networks across multiple CDNs is required to make open caching work effectively at scale on a global basis. The Streaming Video Alliance (SVA) has stepped in by setting up its Open Caching Working Group with two primary objectives. The first is to identify the critical components of a non-proprietary caching system, and then secondly establish basic architectural guidelines for implementation of an open caching system.

Lumen, formerly Century Link, is a US telco that operates a major CDN via its Lumen Edge Platform, optimized for latency-sensitive video content. The company’s CDN product specialist Glenn Goldstein is lead editor of the SVA’s Configuration Interface Specifications, a series of documents describing use cases and other technical specifications for interoperability within the CDN and open caching ecosystems. This led to Disney’s choice of Lumen to help standardize CDN configuration metadata to simplify its global distribution and balance loads optimally across multiple CDN networks.

Configuration metadata enabling content to traverse multiple CDNs from different providers is just one aspect of a complex field. For broadcasting and video streaming, metadata is also needed to provide information about specific streams or files, known as essence. Metadata can either be embedded directly into the video content or included as a separate file within an overall media container, such as MP4 or MKV.

Metadata can then describe an entire video file, or specific frames within it, to include timestamps, resolution of the video, file size, ad-insertion points, colour spaces, error messages, and details of variants such as closed captions and language of the audio.

To be useful, metadata must be recognizable by not just CDNs that the content traverses, but also target devices, whether these are set top boxes, smart TVs, PCs or smartphones, in order for content to be displayed correctly.