Video: IP-based Networks for UHD and HDR Video

If you get given a video signal, would you know what type it was? Life used to be simple, an SD signal would decode in a waveform monitor and you’d see which type it was. Now, with UHD and HDR, this isn’t all the information you need. Arguably this gets easier with IP and is possibly one of the few things that does. This video from AIMS helps to clear up why IP’s the best choice for UHD and HDR.

John Mailhot from Imagine Communications joins Wes Simpson from LearnIPVideo.com to introduce us to the difficulties wrangling with UHD and HDR video. Reflecting on the continued improvement of in-home displays’ ability to show brighter and better pictures as well as the broadcast cameras’ ability to capture much more dynamic range, John’s work at Imagine is focussed on helping broadcasters ensure their infrastructure can enable these high dynamic range experiences. Streaming services have a slightly easier time delivering HDR to end-users as they are in complete control of the distribution chain whereas often in broadcast, particularly with affiliates, there are many points in the chain which need to be HDR/UHD capable.

John starts by looking at how UHD was implemented in the early stages. UHD, being twice the horizontal and twice the vertical resolution of HD is usually seen as 4xHD, but, importantly, John points out that this is true for resolution but, as most HD is 1080i, it also represents a move to 1080p, 3Gbps signals. John’s point is that this is a strain on the infrastructure which was not necessarily tested for initially. Given the UHD signal, initially, was carried by four cables, there is now 4 times the chance of a signal impairment due to cabling.

Square Division Multiplexing (SQD) is the ‘most obvious’ way to carry UHD signals with existing HD infrastructure. The picture is simply cut into four quarters and each quarter is sent down one cable. The benefit here is that it’s easy to see which order the cables need to be connected to the equipment. The downsides included a frame-buffer delay (half a frame) each time the signal was received, difficulties preventing drift of quadrants if they were treated differently by the infrastructure (i.e. there was a non-synced hand-off). One important problem is that there is no way to know an HD feed is from a UHD set or just a lone 3G signal.

2SI, two-sample interleave, was another method of splitting up the signal which was standardised by SMPTE. This worked by taking a pair of samples and sending them down cable 1, then the next pair down cable 2, the pair of samples under the first pair went down cable 3 then the pair under 2 went down 4. This had the happy benefit that each cable held a complete picture, albeit very crudely downsampled. However, for monitoring applications, this is a benefit as you can DA one feed and send this to a monitor. Well, that would have been possible except for the problem that each signal had to maintain 400ns timing with the others which meant DAs often broke the timing budget if they reclocked. It did, however, remove the half-field latency burden which SQD carries. The main confounding factor in this mechanism is that looking at the video from any cable on a monitor isn’t enough to understand which of the four feeds you are looking at. Mis-cabling equipment leads to subtle visual errors which are hard to spot and hard to correct.

Enter the VPID, the Video Payload ID. SD SDI didn’t require this, HD often had it, but for UHD it became essential. SMPTE ST 425-5:2019 is the latest document explaining payload ID for UHD. As it’s version five, you should be aware that older equipment may not parse the information in the correct way a) as a bug and b) due to using an old standard. The VPID carries information such as interlaced/progressive, aspect ratio, transfer characteristics (HLG, SDR etc.), frame rate etc. John talks through some of the common mismatches in interpretation and implementation of VPID.

12G is the obvious baseband solution to the four-wires problem of UHD. Nowadays the cost of a 12G transceiver is only slightly more than 3G ones, therefore 12G is a very reasonable solution for many. It does require careful cabling to ensure the cable is in good condition and not too long. For OB trucks and small projects, 12G can work well. For larger installations, optical connections are needed, one signal per fibre.

The move to IP initially went to SMPTE ST 2022-6, which is a mapping of SDI onto IP. This meant it was still quite restrictive as we were still living within the SDI-described world. 12G was difficult to do. Getting four IP streams correctly aligned, and all switched on time, was also impractical. For UHD, therefore SMPTE ST 2110 is the natural home. 2110 can support 32K, so UHD fits in well. ST 2110-22 allows use of JPEG XS so if the 9-11Gbps bitrate of UHDp50/60 is too much it can be squeezed down to 1.5Gbps with almost no latency. Being carried as a single video flow removes any switch timing problems and as 2110 doesn’t use VPID, there is much more flexibility to fully describe the signal allowing future growth. We don’t know what’s to come, but if it’s different shapes of video rater, new colour spaces or extensions needed for IPMX, these are possible.

John finishes his conversation with Wes mentioning two big benefits of moving to IT-based infrastructure. One is the ability to use the free Wireshark or EBU List tools to analyse video. Whilst there are still good reasons to buy test equipment, the fact that many checks can be done without expensive equipment like waveform monitors is good news. The second big benefit is that whilst these standards were being made, the available network infrastructure has moved from 25 to 100 to 400Gbps links with 800Gbps coming in the next year or two. None of these changes has required any change in the standards, unlike with SDI where improvements in signal required improvements in baseband. Rather, the industry is able to take advantage of this new infrastructure with no effort on our part to develop it or modify the standards.

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Speakers

John Mailhot John Mailhot
Systems Architect, IP Convergence,
Imagine Communications
Wes Simpson Wes Simpson
RIST AG Co-Chair, VSF
President & Founder, LearnIPvideo.com

Video: UHD – commercial success or work in progress?

Where is UHD? Whilst the move to HD for US primetime slots happened very quickly, HD had actually taken many years to gain a hold on the market. Now, though SD services are still numerous, top tier channels all target HD and in terms of production, SD doesn’t really exist. Is UHD successfully building the momentum needed to dominate the market in the way that HD does or are there blockers? Is there the will but not the bandwidth? Can we show that UHD makes financial sense for a business? This video from the DVB Project and UltraHD Forum answers these questions.

Ian Nock takes the mic first and explains the UltraHD Forum’s role in the industry ahead of introducing Dolby’s Jason Power. Ian explains that the UltraHD Forum isn open organisation focused on all aspects of Ultra High Definition including HDR, Wide Colour Gamut (WCG), Next Generation Audio (NGA) and High Frame Rate (HFR). Jason Power is the chair of the DVB Commercial Module AVC. See starts by underlining the UHD-1 Phase 1 and Phase 2 specifications. Phase 1 defines the higher resolution and colour gamut, but phase 2 delivers higher frame rate, better audio and HDR. DVB works to produce standards that define how these can be used and the majority of UHD services available are DVB compliant.

On the topic of available services, Ben Schwarz takes the stand next to introduce the UltraHD Forum’s ‘Service Tracker‘ which tracks the UHD services available to the public around the world. Ben underlines there’s been a tripling of services available between 2018 to 2020. It allows you to order by country, look at resolution (from 2K to 8L) and more. Ben gives a demo and explains the future plans.

Paul Bray focusses on the global television set business. He starts looking at how the US and Europe have caught up with China in terms of shipments but the trend of buying a TV set – on average – an inch larger than the year before, shows little sign of abating. A positive for the industry, in light of Covid-19, is that the market is not predicted to shrink. Rather, the growth that was expected will be stunted. The US replaces TVs more often than other countries, so the share of TVs there which are UHD is higher than anywhere else. Europe still has a large proportion of people who are happy with 32″ TVs due to the size and HD is perfectly ok for them. Paul shows a great graph which shows the UHD Penetration of each market against the number of UHD services available. We see that Europe is notably in the lead and that China barely has any UHD services at all. Though it should be noted that Omdia are counting linear services only.

Graph showing UHD Penetration per geographical market Vs. Number of Linear UHD services in that Market

Graph showing UHD Penetration per geographical market Vs. Number of Linear UHD services.
Graph and Information ©Omdia

The next part of the video is a 40-minute Q&A which includes Virginie Drugeon who explains her work in defining the dynamic metadata that is sent to the receiver so that it can correctly adapt the picture, particularly for HDR, to the display itself. The Q&A covers the impacts of Covid-19, recording formats for delivery to broadcasters, bitrates on satellite, the UltraHD Forum’s foundational guidelines, new codecs within DVB, high frame rate content and many other topics.

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Download the presentations
Speakers

Jason Power Jason Power
Chair of the DVB Commercial Module AVC Working Group
Commercial Partnerships and Standards, Dolby Laboratories
Ben Schwarz Ben Schwarz
Chair of Ultra HD Forum Communication Working Group
Paul Gray Paul Gray
Research Director,
Omdia
Virginie Drugeon Virginie Drugeon
Senior Engineer, Digital Standardisation,
Panasonic
Ian Nock Moderator:Ian Nock
Chair of the Interoperability Working Group of the Ultra HD Forum
Principal Consultant & Founder, Fairmile West

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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Free registration required

Speaker

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