Brad Gilmer Archives – The Broadcast Knowledge

Video: Deterministic Video Switching in IP Networks

Posted on 19th July 2021 by Russell Trafford-Jones

The broadcast industry spent a lot of time getting synchronous cuts working in analogue and SDI. Now IP is being used more and more, there’s a question to be asked about whether video switching should be done in the network itself or at the video level within the receiver. Carl Ostrom from the VSF talks us through the pros and cons of video switching within the network itself along with Brad Gilmer

First off, switching video at a precise point within the stream is known as ‘deterministic switching’. The industry has become used to solid-state crosspoint switching which can be precisely timed so that the switch happens within the vertical blanking interval of the video providing a hitless switch. This isn’t a hitless switch in the meaning of SMPTE ST 2022-7 which allows kit to switch from one identical stream to another to deal with packet loss, this is switching between two different streams with, typically, different content. With the move to ST 2110, we have the option of changing the destination of packets on the fly which can achieve this same switching with the benefit of saving bandwidth. For a receiving device to do a perfect switch, it would need to be receiving both the original video and next video simultaneously, doubling the incoming bandwidth. Not only does this increase the bandwidth, but it can also lead to uneven bandwidth.

Carl’s open question to the webinar attendees is whether network switching is needed and invites Thomas Edwards from the audience to speak. Thomas has previously done a lot of work proposing switching techniques and has also demonstrated that the P4 programming language for switches can actually successfully manipulate SMPTE ST 2110 traffic in real-time as seen in this demo. Thomas comments that bandwidth within networks built for 2110 doesn’t seem to a problem so subscribing to two streams is working well. We hear further comments regarding network-based switching and complexity. possibly also driving up the costs of the switches themselves. Make before break can also be a simpler technology to fault find when a problem occurs.

Watch now!
Speakers

	Carl Ostrom Vice President, VSF
	Brad Gilmer Executive Director, Video Services Forum Executive Director, Advanced Media Workflow Association (AMWA)

Video: IP Systems – The Big Picture

Posted on 6th July 2021 by Russell Trafford-Jones

Early adopters of IP are benefiting from at least one of density, flexibility and scalability which are some of the promises of the technology. For OB vans, the ability to switch hundreds of feeds within only a couple rack units is incredibly useful, for others being able to quickly reconfigure a room is very valuable. So whilst IP isn’t yet right for everyone, those that have adopted it are getting from it benefits which SDI can’t deliver. Unfortunately, there are aspects of IP which are more complex than older technology. A playback machine plugged into an SDI router needed no configuration. However, the router and control system would need to be updated manually to say that a certain input was now a VT machine. In the IP world, the control system can discover the new device itself reducing manual intervention. In this situation, the machine also needs an IP configuration which can be done manually or automatically. If manual, this is more work than before. If automatic, this is another service that needs to be maintained and understood.

Just like the IT world is built on layers of protocols, standards and specifications, so is a modern broadcast workflow. And like the OSI model which helps break down networking into easy to understand, independent layers such as cabling (layer 1), point to point data links (layer 2), the network layer (3) etc. It’s useful to understand IP systems in a similar way as this helps reduce complexity. The ‘Networked Media System Big Picture’ is aimed at helping show how a professional IP media system is put together and how the different parts of it are linked – and how they are not linked. It allows a high-level view to help explain the concepts and enables you to add detail to explain how each and every protocol, standard and specification are used and their scope. The hope is that this diagram will aid everyone in your organisation to speak in a common language and support conversations with vendors and other partners to avoid misunderstandings.

Brad Gilmer takes us through the JT-NM’s diagram which shows that security is the bottom layer for the whole system meaning that security is all-encompassing and important to everything. Above the security layer is the monitoring layer. Naturally, if you can’t measure how the rest of your system is behaving, it’s very hard to understand what’s wrong. For lager systems, you’ll be wanting to aggregate the data and look for trends that may point to worsening performance. Brad explains that next are the control layer and the media & infrastructure layer. The media and infrastructure layer contains tools and infrastructure needed to create and transport professional media.

Towards the end of this video, Brad shows how the diagram can be filled in and highlighted to show, for instance, the work that AMWA has done with NMOS including work in progress. He also shows the parts of the system that are within the scope of the JT-NM TR 1001 document. These are just two examples of how to use the diagram to frame and focus discussions demonstrating the value of the work undertaken.

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Speaker

	Brad Gilmer Executive Director, Video Services Forum Executive Director, Advanced Media Workflow Association (AMWA)
	Moderator: Wes Simpson LearnIPVideo.com

Video: A Frank Discussion of NMOS

Posted on 21st June 2021 by Russell Trafford-Jones

What NMOS isn’t is almost as important as what NMOS actually is when it comes to defining a new project implementing SMPTE ST 2110. Written by AMWA, NMOS is a suite of open specifications which help control media flow hence the name: Network Media Open Specifications. Typically NMOS specifications are used alongside the ST 2110 standards but in this hype-free panel, we hear that 2110 isn’t the only application of NMOS.

AMWA Executive Director Brad Gilmer introduces this ‘frank’ panel with Imagine’s John Mailhot explaining the two meanings ‘NMOS’ has. The first is the name of the project we have just introduced in this article. The second is as shorthand for the two best-known specifications created by the project, IS-04 and IS-05. Together, these allow new devices to register their availability to the rest of the system and to receive instructions regarding sending media streams. There are plenty of other specifications which are explained in this talk of which two more are mentioned later in this video: IS-08 which manages audio channel mapping and IS-09 which allows new devices to get a global configuration to automatically find out facts like their PTP domain.

Security is “important and missing previously,” says Jed Deame from Nextera but explains that since NMOS is predominantly a specification for HTTP API calls, there is nothing to stop this from happening as HTTPS or another protocol as long as it provides both encryption and authorisation. The panel then explores the limits of the scope of NMOS. For security, its scope is to secure the NMOS control traffic, so doesn’t stretch to securing the media transport or, say, PTP. Furthermore, for NMOS as a whole, it’s important to remember it defines control and not more than control. Brad says, though, that even this scope is ambiguous as where does the concept of ‘control’ stop? Is a business management system control? What about scheduling of media? Triggering playback? There have to be limited.

Imagine Communications’ John Mailhot explores the idea of control asking how much automation, and hence NMOS-style control, can help realise one of the promises of IP which is to reduces costs by speeding up system changes. Previously, Brad and John explain, changing a studio from doing NFL to doing NHL may take up to a month of rewiring and reprogramming. Now that rewiring can be done in software, John contends that the main task is to make sure the NMOS is fully-fledged enough to allow interoperable enumeration, configuration and programming of links within the system. The current specifications are being reinforced by ‘modelling’ work whereby the internal logical blocks of equipment, say an RGB gain control, can be advertised to the network as a whole rather than simply advertising a single ‘black box’ like an encoder. Now it’s possible to explain what pre and post-processing is available.

Another important topic explored by NVIDIA’s Richard Hastie and Jeremy Nightingale from Macnica, is the use of NMOS specifications outside of ST 2110 installations. Richard says that NVIDIA is using NMOS in over 200 different locations. He emphasises its use for media whether that be HEVC, AV1 or 2110. As such, he envisages it being used by ‘Twitch streamers’ no doubt with the help of the 2110-over-WAN work which is ongoing to find ways to expose NMOS information over public networks. Jeremy’s interest is in IPMX for ProAV where ‘plug and play’ as well as security are two of the main features being designed into the package.

Lastly, there’s a call out to the tools available. Since NMOS is an open specification project, the tools are released as Open Source which companies being encouraged to use the codebase in products or for testing. Not only is there a reference client, but Sony and BBC have released an NMOS testing tool and EasyNMOS provides a containerised implementation of IS-04 and IS-05 for extremely quick deployments of the toolset.

Watch now!
Speakers

	Brad Gilmer Executive Director, Video Services Forum Executive Director, Advanced Media Workflow Association (AMWA)
	John Mailhot CTO Networking & Infrastructure
	Jed Deame CEO, Nextera Video
	Richard Hastie Senior Sales Director, NVIDIA
	Jeremy Nightingale President Macnica Americas, Inc.

Webinar: Building Large SMPTE ST 2110 Systems Using JT-NM TR-1001-1

Posted on 10th January 2019 by Russell Trafford-Jones

When? 10th Jan 2019. 1:00 PM EST / 10:00 AM PST / 18:00 GMT

TR 1001-1 from the JT-NM (Joint Task Force on Networked Media) gives guidance on protocols, configuration and architectures to use when setting up large ST-2110 systems.

John Mailhot and Brad Gilmer, both well trusted industry figures who are in the thick of creating and testing ST-2110 and the surrounding specifications, will lead us through what it is, what it tells us and, ultimately, how we can best go about creating a large ST 2110 system.

Speakers

	John Mailhot CTO, Networking & Infrastructure, Imagine Communications
	Brad Gilmer President, Gilmer & Associates & Executive Director of the Video Services Forum (VSF)

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