Video: Edge Compute and the CDN

Requests to servers are returned only tens of milliseconds later which is hardly any time to wait. But they quickly add up to users waiting seconds for their player to find out what video it wants, get it and finally start showing it. We all know that time is money when it comes to people ‘pressing play’ so reducing this startup time.

Anime streaming service, CrunchyRoll went to task to reduce their startup time. Michael Dale, VP of Engineering there, sits with Heather Chamberlin Mellish from AWS to describe how they used AWS to optimise the communications needed to establish a streaming session,

Named Katana, the project looked at the 12+ requests involved between third parties and the player itself which were all needed to start the session. Advertising companies need to be consulted, streaming manifest files need to represent chunks from multiple CDNs, SSAI and metrics were done with third-party vendors and the service is protected with DRM. These are just some of the factors which led to so many return trips needing to be accomplished before shipping.

This talk provides an overview and a little bit of a ‘behind the scenes’ of a blog post which also covers this project.

Key to success was deploying on AWS [email protected] which is a server which allows you to run code within AWS’s CloudFront. If you have Python or Javascript, this allows you to run it at the edge server closest to the user. For Crunchyroll’s global audience, this is particularly useful as it avoids having to set up infrastructure in every one of the AWS regions but still reduces much of the return trip time. Michael explains that, although Lambda is often viewed as an ephemeral service, when it’s not in use it can be suspended and used again in the future allowing it to maintain state for a player.

Michael explains the ways in which Katana has achieved success. Many of the third-party services have been brought into [email protected] and AWS. DRM and Advertising are still third-party, but doing most things within the edge and also pre-emptively returning information such as manifests has removed many requests. The video breaks down their use of GraphQL and how Multi-CDN and SSAI workflows have been implemented.

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Speakers

Michael Dale Michael Dale
VP Engineering,
Crunchyroll
Heather Mellish Heather Chamberlin Mellish
Principal Edge Go To Market Specialist,
AWS Amazon Web Services

Video: Reliable and Uncompressed Video on AWS

Uncompressed video in the cloud is an answer to the dreams that many people are yet to have, but the early adopters of cloud workflows, those that are really embedding the cloud into their production and playout efforts are already asking for it. AWS have developed a way of delivering this between computers within their infrastructure and have invited a vendor to explain how they are able to get this high-bandwidth content in and out.

On The Broadcast Knowledge we don’t normally feature such vendor-specific talks, but AWS is usually the sole exception to the rule as what’s done in AWS is typically highly informative to many other cloud providers. In this case, AWS is first to the market with an in-prem, high-bitrate video transfer technology which is in itself highly interesting.

LTN’s Alan Young is first to speak, telling us about the traditional broadcast workflows of broadcasters giving the example of a stadium working into the broadcaster’s building which then sends out the transmission feeds by satellite or dedicated links to the transmission and streaming systems which are often located elsewhere. LTN feel this robs the broadcaster of flexibility and cost savings from lower-cost internet links. The hybrid that he sees working in medium-term is feeding the cloud directly from the broadcaster. This allows production workflows to take place in the cloud. After this has happened, the video can either come back to the broadcaster before on-pass to transmission or go directly to one or more of the transmission systems. Alan’s view is the interconnecting network between the broadcaster and the cloud needs to be reliable, high quality, low-latency and able to handle any bandwidth of signal – even uncompressed.

Once in the cloud, AWS Cloud Digital Interface (CDI) is what allows video to travel reliably from one computer to another. Andy Kane explains what the drivers were to create this product. With the mantra that ‘gigabits are the new megabits’, they looked at how they could move high-bandwidth signals around AWS reliably with the aim of abstracting the difficulty of infrastructure away from the workflow. The driver for uncompressed in the cloud is reducing re-encoding stages since each of them hits latency hard and, for professional workflows, we’re trying to keep latency as close to zero as possible. By creating a default interface, the hope is that inter-vendor working through a CDI interface will help interoperability. LTN estimate their network latency to be around 200ms which is already a fifth of a second, so much more latency on top of that is going to creep up to a second quite easily.

David Griggs explains some of the technical detail of CDI. For instance, it has the ability to send data of any format be that raw packetised video, audio, ancillary data or compressed data using UDP, multicast between EC2 instances within a placement group. With a target latency of less than one frame, it’s been tested up to UHD 60fps and is based on the Elastic Fabric Adapter which is a free option for EC2 instances and uses kernel bypass techniques to speed up and better control network transfers. CPU use scales linearly so where 1080p60 takes 20% of a CPU, UHD would take 80%. Each stream is expected to have its own CPU.

The video ends with Alan looking at the future where all broadcast functionality can be done in the cloud. For him, it’s an all-virtual future powered by the increasingly accessible high-bandwidth internet connectivity coming in a less than the cost of bespoke, direct links. David Griggs adds that this is changing the financing model moving from a continuing effort to maximise utilisation of purchased assets, to a pay as you go model using just the tools you need for each production.

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Please note, if you follow the direct link the video featured in this article is the seventh on the linked page.

Speakers

David Griggs David Griggs
Senior Product Manager,
AWS
Andy Kane Andy Kane
Principal Business Development Manager,
AWS
Alan Young Alan Young
CTO and Head of Strategy,
LTN Global

Video: AV1 Commercial Readiness Panel

With two years of development and deployments under its belt, AV1 is still emerging on to the codec scene. That’s not to say that it’s no in use billions of times a year, but compared to the incumbents, there’s still some distance to go. Known as very slow to encode and computationally impractical, today’s panel is here to say that’s old news and AV1 is now a real-time codec.

Brought together by Jill Boyce with Intel, we hear from Amazon, Facebook, Googles, Amazon, Twitch, Netflix and Tencent in this panel. Intel and Netflix have been collaborating on the SVT-AV1 encoder and decoder framework for two years. The SVT-AV1 encoder’s goal was to be a high-performance and scalable encoder and decoder, using parallelisation to achieve this aim.

Yueshi Shen from Amazon and Twitch is first to present, explaining that for them, AV1 is a key technology in the 5G area. They have put together a 1440p, 120fps games demo which has been enabled by AV1. They feel that this resolution and framerate will be a critical feature for Twitch in the next two years as computer games increasingly extend beyond typical broadcast boundaries. Another key feature is achieving an end-to-end latency of 1.5 seconds which, he says, will partly be achieved using AV1. His company has been working with SOC vendors to accelerate the adoption of AV1 decoders as their proliferation is key to a successful transition to AV1 across the board. Simultaneously, AWS has been adding AV1 capability to MediaConvert and is planning to continue AV1 integration in other turnkey content solutions.

David Ronca from Facebook says that AV1 gives them the opportunity to reduce video egress bandwidth whilst also helping increase quality. For them, SVT-AV1 has brought using AV1 into the practical domain and they are able to run AV1 payloads in production as well as launch a large-scale decoder test across a large set of mobile devices.

Matt Frost represent’s Google Chrome and Android’s point of view on AV1. Early adopters, having been streaming partly using AV1 since 2018 in resolution small and large, they have recently added support in Duo, their Android video-conferencing application. As with all such services, the pandemic has shown how important they can be and how important it is that they can scale. Their move to AV1 streaming has had favourable results which is the start of the return on their investment in the technology.

Google’s involvement with the Alliance for Open Media (AOM), along with the other founding companies, was born out of a belief that in order to achieve the scales needed for video applications, the only sensible future was with cheap-to-deploy codecs, so it made a lot of sense to invest time in the royalty-free AV1.

Andrey Norkin from Netflix explains that they believe AV1 will bring a better experience to their members. Netflix has been using AV1 in streaming since February 2020 on android devices using a software decoder. This has allowed them to get better quality at lower bitrates than VP9 Testing AV1 on other platforms. Intent on only using 10-bit encodes across all devices, Andrey explains that this mode gives the best efficiency. As well as being founding members of AoM, Netflix has also developed AVIF which is an image format based on AV1. According to Andrey, they see better performance than most other formats out there. As AVIF works better with text on pictures than other formats, Netflix are intending to use it in their UI.

Tencent’s Shan Liu explains that they are part of the AoM because video compression is key for most Tencent businesses in their vast empire. Tencent cloud has already launched an AV1 transcoding service and support AV1 in VoD.

The panel discusses low-latency use of AV1, with Dave Ronca explaining that, with the performance improvements of the encoder and decoders along-side the ability to tune the decode speed of AV1 by turning on and off certain tools, real-time AV1 are now possible. Amazon is paying attention to low-end, sub $300 handsets, according to Yueshi, as they believe this will be where the most 5G growth will occur so site recent tests showing decoding AV1 in only 3.5 cores on a mobile SOC as encouraging as it’s standard to have 8 or more. They have now moved to researching battery life.

The panel finishes with a Q&A touching on encoding speed, the VVC and LCEVC codecs, the Sisvel AV1 patent pool, the next ramp-up in deployments and the roadmap for SVT-AV1.

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Speakers

Yueshi Shen Yueshi Shen
Principle Engineer
AWS & Twitch
David Ronca David Ronca
Video Infrastructure Team,
Facebook
Matt Frost Matt Frost
Product Manager, Chome Media Technologies,
Google
Andrey Norkin Andrey Norkin
Emerging Technologies Team
Netflix
Shan Liu Dr Shan Liu
Chief Scientist & General Manager,
Tencent Media Lab
Jill Boyce Jill Boyce
Intel