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How to Deploy a Unified Delivery Model for DASH and HLS at Scale

July 21, 2020
3-Minute Read
Director of Innovation for Digital Television Applications

The video industry has been working hard to create a unified delivery workflow for the predominant streaming formats HLS and DASH that can provide the same quality level as traditional broadcast. Having separate delivery workflows for the different streaming formats creates additional costs related to processing, caching and storage. It also means more complexity.

The journey to reach this goal was long but now with Apple’s recent announcement to fully support the low-latency HLS extension in its devices running iOS14 in the fall 2020, all pieces of the puzzle are on the table.

Several challenges, mainly related to latency and monetization, have stood in the way of achieving a unified workflow for video streaming. However, today the industry is getting closer to its goal thanks to the efforts made to reduce duplicate low-latency streaming workflows, and by bringing monetization front and center. For the video streaming business there are different approaches to implement monetization. You can use the DRM for subscription services, or Dynamic Ad Insertion (DAI) for ad-sponsored services.  Low latency, and monetization are essential in a unified delivery model. Here are the steps to success.


Ensure reliable low-latency streaming without duplicate workflows

It is imperative that the OTT industry achieves the same latency for OTT as traditional broadcast of live content. Viewers don’t want to see a noticeable delay between a live video stream and the broadcast. The MPEG DASH format and Apple’s new HLS extension to support low latency are now solid, and the ecosystem, including encoder, packager, origin, CDN and player, is mature enough to support these extensions. They both rely on CMAF for the content format. These are examples of how the industry is answering this issue.

Although the low-latency extension for the existing DASH and HLS specifications are both based on segment using CMAF format, this doesn’t fully solve the workflow separation issue. As of today, we still need two separate ecosystems for the delivery of live content in DASH and HLS. Having duplicate workflows increases service providers overall costs, increases complexity and puts more stress on the OTT business model, slowing down OTT deployments.

To mitigate this issue, Apple and many streaming industry players, including technology solution providers for encoding, packaging, origin, CDN and OTT players, agreed to work together on finding a compatible mode between DASH and HLS for low-latency content delivery. This is a positive step in the right direction.

This work stems from the CTA/Wave project umbrella, and it is anticipated to provide recommendations and suggested evolutions for both DASH and HLS specifications in order to make unique workflows possible for these streaming formats. Once we create a common format for media files and a common delivery workflow, we can then truly realize low latency for live OTT service delivery, without any of the cost and complexity limitations.


Simplify monetization for video streaming

Over the years, finding a sustainable business model has been a challenge for OTT. To monetize content, OTT service providers need DRM and/or ad insertion tools, depending on their subscription model. There also needs to be a common way to support these features within the OTT delivery workflow.

Recently, unified support for the CBCS encryption scheme became available on all the major DRM systems such as Apple FairPlay for HLS, and Google Widevine and Microsoft PlayReady for DASH. As a result, a single media file can now be encrypted in the CBCS scheme and distributed to any player, regardless of the DRM system.

While dynamic and targeted ad insertion can make ads more relevant, service providers need to ensure a seamless video experience. Both DASH and HLS Low Latency specifications are currently being analyzed to ensure that legacy workflows can be used or slightly adapted to consider the additional constraints of having a shorter delivery path. It’s an ongoing process, and, as part of the expected outcome of the CTA/Wave project, HLS and DASH guidelines will be updated to properly use the timing information for inserting ads in the low-latency streams.


Reaching new levels of efficiency for live OTT

Delivering OTT video streaming with low latency is critical, especially for highly valuable content such as premium sports, which attracts a large audience. It’s even more imperative for streaming applications that are coupled with real-time engagement on social media platforms. But latency also has an impact on monetization.

For video streaming be successful and profitable, targeted ads need to be a part of the OTT streaming equation. Once the industry has developed a unified CMAF-based live OTT streaming system that supports common encryption (which has already done with CBCS), ad insertion and low latency for both HLS and DASH, we can greatly reduce processing, storage and delivery costs. What’s more — we can truly monetize the OTT video streaming experience.

Harmonic is an industry leader for media processing and delivery. Using our VOS360 platforms, you can improve subscriber’s experience with high-quality video and simultaneously simplify your workflows. Get in touch with us today to learn more about how we can help your business unify your OTT and broadcast workflows.


Patrick Gendron is Director of Innovation at Harmonic for Digital Television Applications. He joined Harmonic with the acquisition of Thomson Video Networks. Patrick recently moved from managing the Harmonic R&D Innovation team to the Marketing Innovation & Evangelism team and is Harmonic’s representative at DASH IF, DVB TM and Streaming Video Alliance. Previously, Patrick held senior program and engineering management positions in the digital television headend domain, with international R&D management activities, at Grass Valley and Nextream. He started his career as a research engineer at the Laboratoires Electronique de Rennes (Thomson CSF) where he developed new technologies for professional video transmission over optical fiber (long-haul, single-mode links). As digital technology was maturing for television applications, he moved to Thomson Broadband Systems in a project management role for a number of first-generation digital TV products such as satellite modulators and contribution MPEG codecs. Patrick is a graduate in Computer Science and Telecommunications from the Ecole Supérieure d’Electricité (Supélec).

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