Amazon Web Services Archives – The Broadcast Knowledge

Video: Uncompressed Video in the Cloud

Posted on 12th July 2021 by Russell Trafford-Jones

Moving high bitrate flows such as uncompressed media through cloud infrastructure = which is designed for scale rather than real-time throughput requires more thought than simply using UDP and multicast. That traditional approach can certainly work, but is liable to drop the occasional packet compromising the media.

In this video, Thomas Edwards and Evan Statton outline the work underway at Amazon Web Services (AWS) for reliable real-time delivery. On-prem 2110 network architectures usually have two separate networks. Media essences are sent as single, high bandwidth flows over both networks allowing the endpoint to use SMPTE ST 2022-7 seamless switching to deal with any lost packets. Network architectures in the cloud differ compared to on-prem networks. They are usually much wider and taller providing thousands of possible paths to get to any one destination.

AWS have been working to find ways of harnessing the cloud network architectures and have come up with two protocols. The first to discuss is Scalable Reliable Delivery, SRD, a protocol created by Amazon which guarantees delivery of packets. Delivery is likely to be out of order, so packet order needs to be restored by a layer above SRD. Amazon have custom network cards called ‘Nitro’ and it’s these cards which run the SRD protocol to keep the functionality as close to the physical layer as possible.

SRD capitalises on hyperscale networks by splitting each media flow up into many smaller flows. A high bandwidth uncompressed video flow could be over 1 Gbps. SRD would deliver this over one or more hundred ‘flowlets’ each leaving on a different path. Paths are partially controlled using ECMP, Equal Cost Multipath, routing whereby the egress port used on a switch is chosen by hashing together a number of parameters such as the source IP and destination port. The sender controls the ECMP path selection by manipulating packet encapsulation. SRD employs a specialized congestion control algorithm that helps further decrease the chance of packet drops and minimize retransmit times, by keeping queuing to a minimum. SRD keeps an eye on the RTT (round trip time) of each of the flowlets and adjusts the bandwidth appropriately. This is particularly useful as a way to deal with the problem where upstream many flowlets may end up going through the same interface which is close to being overloaded, known as ‘incast congestion’. In this way, SRD actively works to reduce latency and congestion. SRD is able to monitor round trip time since it also has a very small retransmit buffer so that any packets which get lost can be resent. Similar to SRT and RIST, SRD does expect to receive acknowledgement packets and by looking at when these arrive and the timing between packets, RTT and bandwidth estimations can be made.

CDI, the Cloud Digital Interface, is a layer on top of SRD which acts as an interface for programmers. Available on Github under a BSD licence, it gives access to the incoming essence streams in a way similar to SMPTE’s ST 2110 making it easy to deal with pixel data, get access to RGB graphics including an alpha layer as well as providing metadata information for subtitles or SCTE 104 signalling.

	Thomas Edwards Principal Solutions Architect & Evangelist, Amazon Web Services
	Evan Statton Principal Architect, Amazon Web Services (AWS)

Video: Workflow Evolution Within the CDN

Posted on 22nd June 2021 by Russell Trafford-Jones

The pandemic has shone a light on CDNs as they are the backbone of much of what we do with video for streaming and broadcast. CDNs aim to scale up in a fast, sophisticated way so you don’t have to put in the research to achieve this yourself. This panel from the Content Delivery Summit sees Dom Robinson bringing together Jim Hall from Fastly with Akamai’s Peter Chave, Ted Middleton from Amazon and Paul Tweedy from BBC Design + Engineering.

The panel discusses the fact that although much video conferencing traffic being WebRTC isn’t supported, there are a lot of API calls that are handled by the CDN. In fact, over 300 trillion API calls were made to Amazon last year. Zoom and other solutions do have an HLS streaming option that has been used and can benefit from CDN scaling. Dom asks whether people’s expectations have changed during the pandemic and then we hear from Paul as he talks a little about the BBC’s response to Covid.

THE CTA’s Common Media Client Data standard, also known as CTA 5004, is a way for a video player to pass info back to the CDN. In fact, this is so powerful that it can provide highly granular real-time reports for customers but also enables hints to be handed back from the players so the CDNs can pre-fetch content that is likely to be needed. Furthermore, having a standard for logging will be great for customers who are multi-CDN and need a way to match logs and analyse their system in its entirety. This work is also being extended, under a separate specification to be able to look upstream in a CDN workflow to understand the status of other systems like edge servers.

The panel touches on custom-made analytics, low latency streaming such as Apples LL-HLS and why it’s not yet been adopted, current attempts in the wild to bring HLS latency down, Edge computing and piracy.

Watch now!
Speakers

	Peter Chave Principal Architect, Akamai Technologies
	Paul Tweedy Lead Architect, Online Technology Group, BBC Design + Engineering
	Ted Middleton Global Leader – Specialized Solution Architects, Edge Services Amazon
	Jim Hall Principal Sales Engineer, Fastly
	Moderator: Dom Robinson Director and Creative Firestarter, id3as Contributing Editor, StreamingMedia.com, UK

Video: Cloud Services for Media and Entertainment – Processing, Playout and Distribution

Posted on 24th May 2021 by Russell Trafford-Jones

What are the options for moving your playout, processing and distribution into the cloud? What will the workflows look like and what are the options for implementing them? This video covers the basics, describes many of the functions available like subtitle generation and QC then leads you through to harnessing machine learning,

SMPTE’s New York section has brought together Evan Statton and Liam Morrison from AWS, Alex Emmermann from Telestream, Chris Ziemer & Joe Ashba from Imagine Communications and Rick Phelps from Brklyn Media to share their knowledge on the topic. Rick kicks off proceedings with a look at the principles of moving to the cloud. He speaks about the need to prepare your media before the move by de-duplicating files, getting the structure and naming correct and checking your metadata is accurate. Whilst deduplicating data reduces your storage costs, another great way to do this is to store in IMF format. IMF, the Interoperable Media Format, is related to MXF and stores essences separately. By using pointers to the right media, new versions of files can re-use media from other files. This further helps reduce storage costs.

Rick finishes by running through workflow examples covering INgest, Remote Editing using PCoIP, Playout and VoD before running through the pros and cons of Public, Private and Hybrid cloud.

Next on the rosta are Chris & Joe outlining their approach to playout in the cloud. They summarise the context and zoom in to look at linear channels and their Versio product. An important aspect of bringing products to the cloud, explains Joe, is to ensure you optimise the product to take advantage of the cloud. Where a software solution on-prem will use servers running the storage, databases, proxy generation and the like, in the cloud you don’t want to simply set up EC2 instances to run these same services. Rather, you should move your database into AWS’s database service, use AWS storage and use a cloud-provided proxy service. This is when the value is maximised.

Alex leads with his learnings about calculating the benefits of cloud deployment focussing on the costs surrounding your server. You have to calculate the costs of the router port it’s connected to and the rest of the network infrastructure. Power and aircon is easy to calculate but don’t forget, Alex says, about the costs of renting the space in a data centre and the problems you hit when you have to lease another cage because you have become full. Suddenly and extra server has led to a two-year lease on datacentre space. He concludes by outlining Telestream’s approach to delivering transcode. QC, playback and stream monitoring in their Telestream Cloud offering.

Evan Statton talks about the reasons that AWS created CDI and they merged the encoding stages for DTH transmission and OTT into one step. These steps came from customers’ wishes to simplify cloud worksflows or match their on-prem experiences. JPEG-XS, for isntance, is there to ensure that ultra low-latency video can flow in and out of AWS with CDI allowing almost zero delay, uncompressed video to flow within the cloud. Evan then looks through a number of workflows: Playout, stadium connectivity, station entitlement and ATSC 3.0.

Liam’s presenation on machine learning in the cloud is the last of this section meeting. Liam focuses he comments and demos on machine learning for video processing. He explains how ML fits into the Articifical Intelligence banner and looks to where the research sector is heading. Machine learning is well suited to the cloud because of the need to have big GPU-heavy servers to manage large datasets and high levels of compute. the G4 series of EC2 servers is singled out as the machine learning instances of choice.

Liam shows demos of super resolution and frame interpolation the later being used to generate slow motion clips, increasing the framerate of videos, improving the smoothness of stop-motion animations and more. Bringing this together, he finishes by showing some 4K 60fps videos created from ancient black and white film clips.

The extensive Q&A looks at a wide range of topics:
The need for operational change management since however close you get the cloud workflows to match what your staff are used to, there will be issues adjusting to the differences.
How to budget due to the ‘transactional’ nature of AWS cloud microservices
Problems migrating TV infrastructure to the cloud
How big the variables are between different workflow designs
When designing cloud workflows, what are the main causes of latency? When fighting latency what are the trade-offs?
How long ML models for upconverting or transcoding take finish training?

Watch now!
Speakers

	Liam Morrison Principal Architect, Machine Learning, Amazon Web Services (AWS)
	Alex Emmermann Cloud Business Development, Telestream
	Joe Ashba Senior Solutions Architect, Imagine Communications
	Chris Ziemer VP Strategic Accounts & Partnerships, Imagine Communications
	Rick Phelps Founder, Brklyn Media
	Evan Statton Principal Architect, Amazon Web Services (AWS)
	Moderator: Ed DeLauter

Video: FOX – Uncompressed live sports in the cloud

Posted on 23rd February 2021 by Russell Trafford-Jones

Is using uncompressed video in the cloud with just 6 frames of latency to get there and back ready for production? WebRTC manages sub-second streaming in one direction and can even deliver AV1 in real-time. The key to getting down to a 100ms round trip is to move down to millisecond encoding and to use uncompressed video in the cloud. This video shows how it can be done.

Fox has a clear direction to move into the cloud and last year joined AWS to explains how they’ve put their delivery distribution into the cloud remuxing feeds for ATSC transmitters, satellite uplinks, cable headends and encoding for internet delivery, In this video, Fox’s Joel Williams, Evan Statton from AWS explain their work together making this a reality. Joel explains that latency is not a very hot topic for distribution as there are many distribution delays. The focus has been on getting the contribution feeds into playout and MCR monitoring quickly. After all, when people are counting down to an ad break, it needs to roll exactly on zero.

Evan explains the approach AWS has taken to solving this latency problem and starts with considering using SMPTE’s ST 2110 in the cloud. ST 2110 has video flows of at least 1 Gbps, typically and when implemented on-premise is typically built on a dedicated network with very strict timing. Cloud datacentres aren’t like that and Evan demonstrates this showing how across 8 video streams, there are video drops of several seconds which is clearly not acceptable. Amazon, however, has a product called ‘Scalable Reliable Datagram’ which is aimed at moving high bitrate data through their cloud. Using a very small retransmission buffer, it’s able to use multiple paths across the network to deliver uncompressed video in real-time. The retransmission buffer here being very small enables just enough healing to redeliver missing packets within the 16.7ms it takes to deliver a frame of 60fps video.

On top of SRD, AWS have introduced CDI, the Cloud Digital Interface, which is able to describe uncompressed video flows in a way already familiar to software developers. This ‘Audio Video Metadata’ layer handles flows in the same way as 2110, for instance keeping essences separate. Evan says this has helped vendors react favourably to this new technology. For them instead of using UDP, SRD can be used with CDI giving them not only normal video data structures but since SRD is implemented in the Nitro network card, packet processing is hidden from the application itself.

The final piece to the puzzle is keeping the journey into and out of the cloud low-latency. This is done using JPEG XS which has an encoding time of a few milliseconds. Rather than using RIST, for instance, to protect this on the way into the cloud, Fox is testing using ST 2022-7. 2022-7 takes in two identical streams on two network interfaces, typically. This way it should end up with two copies of each packet. Where one gets lost, there is still another available. This gives path redundancy which a single stream will never be able to offer. Overall, the test with Fox’s Arizona-based Technology Center is shown in the video to have only 6 frames of latency for the return trip. Assuming they used a California-based AWS data centre, the ping time may have been as low as two frames. This leaves four frames for 2022-7 buffers, XS encoding and uncompressed processing in the cloud.

Watch now!
Speakers

	Joel Wiliams VP of Architecutre & Engineering, Fox Corporation
	Evan Statton Principal Architect, Media & Entertainment, AWS

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