Video: Layer 4 in the CDN

Caching is a critical element of the streaming video delivery infrastructure, but with the proliferation of streaming services, managing caching is complex and problematic. Open Caching is an initiative by the Streaming Video Alliance to bring this under control allowing ISPs and service providers a standard way to operate.

By caching objects as close to the viewer as possible, you can reduce round-trip times which helps reduce latency and can improve playback but, more importantly, moving the point at which content is distributed closer to the customer allows you to reduce your bandwidth costs, and create a more efficient delivery chain.

This video sees Disney Streaming Services, ViaSat and Stackpath discussing Open Caching with Jason Thibeault, Executive Director of the Streaming Video Alliance. Eric Klein from Disney explains that one driver for Open Caching is from content producers which find it hard to scale, to deliver content in a consistent manner across many different networks. Standardising the interfaces will help remove this barrier of scale. Alongside a drive from content producers, are the needs of the network operators who are interested in moving caching on to their network which reduces the back and forth traffic and can help cope with peaks.

Dan Newman from Viasat builds on these points looking at the edge storage project. This is a project to move caching to the edge of the networks which is an extension of the original open caching concept. The idea stretches to putting caching directly into the home. One use of this, he explains, can be used to cache UHD content which otherwise would be too big to be downloaded down lower bandwidth links.

Josh Chesarek from StackPath says that their interest in being involved in the Open Caching initiative is to get consistency and interoperability between CDNs. The Open Caching group is looking at creating these standard APIs for capacity, configuration etc. Also, Eric underlines the interest in interoperability by the close work they are doing with the IETF to find better standards on which to base their work.

Looking at the test results, the average bitrate increases by 10% when using open caching, but also a 20-40% improvement in connection use rebuffer ratio which shows viewers are seeing an improved experience. Viasat have used multicast ABR plus open caching. This shows there’s certainly promise behind the work that’s ongoing. The panel finishes by looking towards what’s next in terms of the project and CDN optimisation.

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Speakers

Eric Klein Eric Klein
Director, CDN Technology,
Disney+
Dan Newman Dan Newman
Product Manager,
Viasat
Josh Chesarek Josh Chesarek
VP, Sales Engineering & Support
Stackpath.com
Jason Thibeault Jason Thibeault
Executive Director, Streaming Video Alliance

Video: Harness SSAI’s Superpowers

Server-side Ad Insertion (SSAI) is a great option for streaming services delivering video to a wide variety of devices and for those who need to avoid ad blockers. Whilst ad insertion can happen in the player, this mechanism can be interfered with allowing users to avoid ads. Whilst client-side ad insertion can much more easily create a unique stream for each client, dynamic SSAI can now do the same with a better user experience.

This panel from the OTT Leadership Summit at Streaming Media West 2019 brings together Disney, WarnerMerdia and Crunchyroll to share their experiences with SSAI. They discuss beaconing, ad standards, scaling, SCTE and more.

Beaconing goes hand in hand with ad playback providing metrics on what happened. When you perform certain actions, the player will reach out to a URL. This can be used to indicate such things as users skipping or pausing a video. The beacon information can then be used to verify how much of which ads were seen by whom and charge advertisers accordingly.

The panel moves on to discussing scaling using live sports as an example and cover questions to ask vendors to ensure you and they are ready for maximum scale. Bandwidth, is declared the biggest challenge, but a less obvious problem is that your upstream ad providers can’t always scale well. If you rely on calls from your server to others, then it’s vital to understand their scaling capacity and strategy. They discuss issues with losing beacons when operating at scale and the need for detailed logging and debugging in order to spot errors and reconcile the results.

Some time is next spent on VPAID and VAST 4 which are both messaging specifications to allow ad servers to tell applications which ads to play. The panel discusses the pros and cons in their use for SSAI where the stitcher needs to reach out to and ad server in real time to find out which ads to play.

At the end of the discussion, the panel takes questions from the floor but not before discussing SCTE Markers and ‘content conditioning’ which surrounds taking care of your source videos and encoder such that the two assets fit together properly at I-frame boundaries.

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Speakers

Robert Jameson Robert Jameson
Technical Director, Media Enablement
Turner | WarnerMedia
Stephen Gray Stephen Gray
Director, Ad Tech Systems
Walt Disney Direct-to-Consumer & International
Michael Dale Michael Dale
VP Engineering,
Crunchyroll
Nadine Krefetz Nadine Krefetz
Consultant, Reality Software
Contributing Editor, Streaming Media