Video: Extension to 4K resolution of a Parametric Model for Perceptual Video Quality

Measuring video quality automatically is invaluable and, for many uses, essential. But as video evolves with higher frame rates, HDR, a wider colour gamut (WCG) and higher resolutions, we need to make sure the automatic evaluations evolve too. Called ‘Objective Metrics’, these computer-based assessments go by the name of PSNR, DMOS, VMAF and others. One use for these metrics is to automatically analyse an encoded video to determine if it looks good enough and should be re-encoded. This allows for the bitrate to be optimised for quality. Rafael Sotelo, from the Universidad de Montevideo, explains how his university helped work on an update to Predicted MOS to do just this.

MOS is the Mean Opinion Score and is a result derived from a group of people watching some content in a controlled environment. They vote to say how they feel about the content and the data, when combined gives an indication of the quality of the video. The trick is to enable a computer to predict what people will say. Rafael explains how this is done looking at some of the maths behind the predicted score.

In order to test any ‘upgrades’ to the objective metric, you need to test it against people’s actual score. So Rafael explains how he set up his viewing environments in both Uruguay and Italy to be compliant with BT.500. BT.500 is a standard which explains how a room should be in order to have viewing conditions which maximise the ability of the viewers to appreciate the pros and cons of the content. For instance, it explains how dim the room should be, how reflective the screens and how they should be calibrated. The guidelines don’t apply to HDR, 4K etc. so the team devised an extension to the standard in order to carryout the testing. This is called ‘subjective testing’.

With all of this work done, Rafael shows us the benefits of using this extended metric and the results achieved.

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Speakers

Rafael Sotelo Rafael Sotelo
Director, ICT Department
Universidad de Montevideo

Video: Deployment of Ultra HD Services Around the Globe

In some parts of the industry UHD is entirely absent. Thierry Fautier is here to shine a light on the progress being made around the globe in deploying UHD.

Thierry starts off by defining terms – important because Ultra HD actually hides several, often unmentioned, formats behind the term ‘UHD’. This also shows how all of the different aspects of UHD, which include colour (WCG), HDR, audio (NGA) and frame rate to name only a few, fit together.

There’s then a look at the stats, where is HDR deployed? How is UHD typically delivered? And the famed HDR Venn diagram showing which TVs support which formats.

As ever, live sports is a major testing ground so the talk examines some lessons learnt, and features a BBC case study, from the 2018 World Cup. Not unrelated, there is a discussion on the state of UHD streaming including discussion of CMAF.

Leading nicely onto Content Aware Encoding (CAE), which was also in use at the world cup.

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Speaker

Thierry Fautier Thierry Fautier
President-Chair, Ultra HD Forum
VP Video Strategy, Harmonic

Video: Intro to 4K Video & HDR

With all the talk of IP, you’d be wrong to think SDI is dead. 12G for 4K is alive and well in many places, so there’s plenty of appetite to understand how it works and how to diagnose problems.

In this double-header, Steve Holmes from Tektronix takes us through the ins and outs of HDR and also SDI for HDR at the SMPTE SF section.

Steve starts with his eye on the SMPTE standards for UHD SDI video looking at video resolutions and seeing that a UHD picture can be made up of 4 HD pictures which gives rise to two well known formats ‘Quad split’ and ‘2SI’ (2 Sample Interleave).

Colour is the next focus and a discussion on the different colour spaces that UHD is delivered with (spoiler: they’re all in use), what these look like on the vector scope and look at the different primaries. Finishing up with a roundup and a look at interlink timing, there’s a short break before hitting the next topic…HDR

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High Dynamic Range is an important technology which is still gaining adoption and is often provided in 4K programmes. Steve defines the two places HDR is important; in the acquisition and the display of the video then provides a handy lookup table of terms such as HDR, WCG, PQ, HDR10, DMCVT and more.

Steve gives us a primer on what HDR is in terms of brightness ‘NITS’, how these relate to real life and how we talk about it with respect to the displays. We then look at HDR on the waveform monitor and look at features of waveform monitors which allow engineers to visualise and check HDR such as false colour.

The topic of gamma, EOTFs and colour spaces comes up next and is well explained building on what came earlier. Before the final demo and Q&A, Steve talks about different ways to grade pictures when working in HDR.

A great intro to the topics at hand – just like Steve’s last one: Uncompressed Video over IP & PTP Timing

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Speakers

Steve Holmes Steve Holmes
Senior Applications Engineer,
Tektronix

Video: ST 2110 – From Theory to Reality

Delivering an all-IP truck is no mean feat. tpc explains what they learnt, what went well and how they succeeded in delivering a truck which takes no longer to fire up than a traditional SDI truck.

A common questions among people considering a move to IP is ‘do I need to?’ and ‘how can I get ready?’. Here at The Broadcast Knowledge we always say ‘find a small project, get it working, learn what goes wrong and then plan the one you really wanted to do.’ The Swiss broadcasting service provider ‘Technology and Production Centre’, known as ‘tpc’, has done just that.

tpc is currently working on the Metechno project – a large all-IP news, sports and technology center for Swiss radio and television. In order to acquire necessary experience with the SMPTE ST 2110 standard, tpc designed the UHD1 OB van ahead of time which has been used in TV production for 6 months now. In this video, Andreas Lattmann shares the vision of the Metechno Project and, critically, his experiences related to the design and use of the truck.

The UHD1 is a 24-camera OB van with all IP core based on Arista switches with non-blocking architecture. It is the equivalent of an 184-square UHD SDI system however, it can be expanded by adding additional line cards to network switches. The truck is format agnostic, supporting both HD and UHD formats in HDR and SDR. IP gateways are incorporated for SDI equipment.

The SMPTE ST 2110 specification separates video and audio into discrete essence streams which boosts efficiency and flexibility, but we hear in this talk that more attention to latency (lip sync) is required compared to SDI systems. Andreas talks about the flexibility this truck provides with up-/down-conversion, color-correction for any video plus how IP has enabled full flexibility in what can be routed to the multiviewer screens.

Anderas spends some time discussing redundancy and how IP enables full redundancy – an improvement over many SDI infrastructures and how SMPTE’s ST 2022-7 standard makes this possible.

The main GUI is based on a Lawo VSM control system which aims to deliver a familiar experience for operators who used to work in the SDI domain. Network training has been provided for all operators because troubleshooting has changed significantly with the introduction of essences over IP. This is not least because NMOS IS-04 and 05 standards were not mature enough during design of the truck, so all IP connections had to be managed manually. With more than 50 thousand IP addresses in this system, AMWA’s NMOS IS-04 which manages discovery and registration and IS-05 which manages the setup and take-down of connections would have helped significantly in the lean management of the truck.

Lattmann emphasizes importance of using open standards like SMPTE ST 2110 instead of proprietary solutions. That allows you to choose the best components and not rely on a single manufacturer.

The learning’s the Andreas presents us involve difficulties with PTP, IP training, the benefits of flexibility. From a video point of view, Andreas presents his experiences with HDR->SDR workflows, focussing in HDR and UHD.

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Speaker

Andreas Lattmann Andreas Lattmann
CTO, Head of Planning & Projects
tpc Switzerland AG