Video: SMPTE Technical Primers

The Broadcast Knowledge exists to help individuals up-skill whatever your starting point. Videos like this are far too rare giving an introduction to a large number of topics. For those starting out or who need to revise a topic, this really hits the mark particularly as there are many new topics.

John Mailhot takes the lead on SMPTE 2110 explaining that it’s built on separate media (essence) flows. He covers how synchronisation is maintained and also gives an overview of the many parts of the SMPTE ST 2110 suite. He talks in more detail about the audio and metadata parts of the standard suite.

Eric Gsell discusses digital archiving and the considerations which come with deciding what formats to use. He explains colour space, the CIE model and the colour spaces we use such as 709, 2100 and P3 before turning to file formats. With the advent of HDR video and displays which can show bright video, Eric takes some time to explain why this could represent a problem for visual health as we don’t fully understand how the displays and the eye interact with this type of material. He finishes off by explaining the different ways of measuring the light output of displays and their standardisation.

Yvonne Thomas talks about the cloud starting by explaining the different between platform as a service (PaaS), infrastructure as a service (IaaS) and similar cloud terms. As cloud migrations are forecast to grow significantly, Yvonne looks at the drivers behind this and the benefits that it can bring when used in the right way. Using the cloud, Yvonne shows, can be an opportunity for improving workflows and adding more feedback and iterative refinement into your products and infrastructure.

Looking at video deployments in the cloud, Yvonne introduces video codecs AV1 and VVC both, in their own way, successors to HEVC/h.265 as well as the two transport protocols SRT and RIST which exist to reliably send video with low latency over lossy networks such as the internet. To learn more about these protocols, check out this popular talk on RIST by Merrick Ackermans and this SRT Overview.

Rounding off the primer is Linda Gedemer from Source Sound VR who introduces immersive audio, measuring sound output (SPL) from speakers and looking at the interesting problem of forward speakers in cinemas. The have long been behind the screen which has meant the screens have to be perforated to let the sound through which interferes with the sound itself. Now that cinema screens are changing to be solid screens, not completely dissimilar to large outdoor video displays, the speakers are having to move but now with them out of the line of sight, how can we keep the sound in the right place for the audience?

This video is a great summary of many of the key challenges in the industry and works well for beginners and those who just need to keep up.

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Speakers

John Mailhot John Mailhot
Systems Architect for IP Convergence,
Imagine Communications
Eric Gsell Eric Gsell
Staff Engineer,
Dolby Laboratories
Linda Gedemer, PhD Linda Gedemer, PhD
Technical Director, VR Audio Evangelist
Source Sound VR
Yvonne Thomas Yvonne Thomas
Strategic Technologist
Digital TV Group

Video: Broadcast 101 – Audio in an IP Infrastructure

Uncompressed audio has been in the IP game a lot longer than uncompressed video. Because of its long history, it’s had chance to create a fair number of formats ahead of the current standard AES67. Since many people were trying to achieve the same thing, we find that some formats are compatible with AES67 – in part, whilst we that others are not compatible.

To navigate this difficult world of compatibility, Axon CTO Peter Schut continues the Broadcast 101 webinar series with this video recorded this month.

Peter starts by explaining the different audio formats available today including Dante, RAVENNA and others and outlines the ways in which they do and don’t interoperate. After spending a couple of minutes summarising each format individually, including the two SMPTE audio formats -30 and -31, he shows a helpful table comparing the,

Timing is next on the list discussing PTP and the way that SMPTE ST 2059 is used then packet time is covered explaining how the RTP payload fits into the equation. This payload directly affects the duration of audio you can fit into a packet. The duration is important in terms of keeping a low latency and is restricted to either 1ms or 125 microseconds by SMPTE ST 2110-30.

Peter finishes up this webinar talking about some further details about the interoperability problems between the formats.

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Speaker

Peter Schut Peter Schut
CTO,
Axon

Video: Real World IP – PTP

PTP, Precision Time Protocol, underpins the recent uncompressed video and audio over IP standards. It takes over the role of facility-wide synchronisation from black and burst signals. So it’s no surprise that The Broadcast Bridge invited Meinberg to speak at their ‘Real World IP’ event exploring all aspects of video over IP.

David Boldt, head of software engineering at Meinberg, explains how you can accurately transmit time over a network. He summarises the way that PTP accounts for the time taken for messages to move from A to B. David covers different types of clock explaining the often-heard terms ‘boundary clock’ and ‘transparent clock’ exploring their pros and cons.

Unlike black and burst which is a distributed signal, PTP is a system with bi-directional communication which makes redundancy all the more critical and, in some ways, complicated. David talks about different ways to attack the main/reserve problem.

PTP is a cross-industry standard which needs to be interpreted by devices to map the PTP time into an understanding of how the signal should look in order for everything to be in time. SMPTE 2059 does this task which David cover.

PTP-over-WAN: David looks at a case study of delivering PTP over a WAN. Commonly assumed not practical by many, David shows how this ways done without using a GPS antenna at the destination. To finish off the talk, there’s a teaser of the new features coming up in the backwards-compatible PTP Version 2.1 before a Q&A.

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Speakers

Daniel Boldt

Daniel Boldt
Head of Software Engineering
Meinberg

Video: BBC Cardiff Central Square – Update

It’s being closely watched throughout the industry, a long-in-the-making project to deploy SMPTE ST 2110 throughout a fully green-field development. Its failure would be a big setback for the push to a completely network-based broadcast workflow.

The BBC Cardiff Central Square project is nearing completion now and is a great example of the early-adopter approach to bringing cutting-edge, complex, large-scale projects to market. They chose a single principle vendor so that they could work closely in partnership at a time when the market for ST 2110 was very sparse. This gave them leverage over the product roadmap and allowed to the for the tight integration which would be required to bring this project to market.

Nowadays, the market for ST 2110 products continues to mature and whilst it has still quite a way to go, it has also come a long way in the past four years. Companies embarking similar projects now have a better choice of products and some may now feel they can start to pick ‘best of breed’ rather than taking the BBC approach. Whichever approach is taken there is still a lot to be gained by following and learning from the mistakes and successes of others. Fortunately, Mark Patrick, Lead Architect on the project is here to provide an update on the project.

Mark starts by giving and overview of the project, its scale and its aims. He presents the opportunities and challenges it presents and the key achievements and milestones passed to date.

Live IP has benefits and risks. Mark takes some time to explain the benefits of the flexibility and increasingly lower cost of the infrastructure and weighs them agains the the risks which include the continually developing standards and skills challenges

The progress overview names Grass Vally as the main vendor, control via BNCS having being designed and virtualised, ST 2110 network topology deployed and now the final commissioning and acceptance testing is in progress.

The media topology for the system uses an principal of an A and a B network plus a separate control network. It’s fundamentally a leaf and spine network and Mark shows how this links in to both the Grass Valley equipment but also the audio equipment via Dante and AES67. Mark takes some time to discuss the separate networks they’ve deployed for the audio part of the project, driven by compatibility issues but also within the constraints of this project, it was better to separate the networks rather than address the changes necessary to force them together.

PTP timing is discussed with a nod to the fact that PTP design can be difficult and that it can be expensive too. NMOS issues are also actively being worked on and remains an outstanding issue in terms of getting enough vendors to support it, but also having compatible systems once an implementation is deployed. This has driven the BBC to use NMOS in a more limited way than desired and creating fall-back systems.

From this we can deduce, if it wasn’t already understood, that interoperability testing is a vital aspect of the project, but Mark explains that formalised testing (i.e. IT-style automated) is really important in creating a uniform way of ensuring problems have been fully addressed and there are no regressions. ST 2110 systems are complex and fault finding can be similarly complex and time consuming.

Mark leaves us by explaining what keeps him awake at night which includes items such as lack of available test equipment, lack of single-stream UHD support and NMOS which leads him to a few comments on ST 2110 readiness such as the need for vendors to put much more effort into configuration and management tools.

Anyone with an interest in IP in broadcast will be very grateful at Mark’s, and the BBC’s, willingness to share the project’s successes and challenges in such a constructive way.

Watch now!

Speaker

Mark Patrick Mark Patrick
Lead Architect,
BBC Major Projects Infrastructure