Defining a technology roadmap for tomorrows television. When it comes to TLA's, its all to play for...

UHD, HDR, WCG, HFR, NDI, NGA, 2SI, HLG, SDQS, PQ, ATSC... Just some of the newest crop of acronyms representing the technologies and standards at the forefront of broadcast innovation today. It's potentially rich pickings for manufacturers, as they compete to become key suppliers in your new workflows. And there's plenty of opportunity for newcomers to this sector to seriously disrupt things.

This article is aimed at those who wish to keep abreast with broadcast technology developments, but are not themselves a technical expert. It offers an overview of the current situation and is written in "producer friendly" terms - although in its nature, it is necessarily quite tech heavy.

With Second Screen, social media and UHD all rapidly developing, there's a lot to keep up with. If you don't feel fully conversant with what's happening to TV technology right now, you will find some explanation and sign-posting of the way(s) ahead within. I've structured things so that the "Techie bit" subheadings can be skimmed or skipped if digits really bore you.

The current landscape

All of the new technology currently being offered gives those in the business of television new and interesting ways to invest in their future. As ever, there are crucial decisions to make. Two significant elements of technological change are happening concurrently, UHD and IP. Together, these offer incredible possibilities to programme makers and broadcasters, and some cavernous pits in which to fall. There's certainly never been a better time to be strategic in your equipment investments. Technology wise, this is the most complicated and game-changing moment broadcast TV has ever seen. And here's why...

UHD

First things first. This isn't like the transition to HD. That was a straightforward "if", which rapidly became "when", followed shortly by "how much". Within reason, all you had to do was pour the required money in - and more pixels came out. Yes, there was also a transition to the widescreen 16:9 format from 4:3, but it was a relatively straightforward (and inexpensive) decision as to how to deal with that. UHD has come out of the traps before the starting gun has fired. It isn't finished yet. But here we are, already making programmes in it.

TV set manufacturers are busy shifting "UHD ready" units, knowing that many of them may well fall short when all standards solidify. Not a significant problem for them, as product cycles are much shorter and production volumes eclipse those of "professional" equipment by several orders of magnitude. But this is not a strategy which broadcasters, programme makers and facilities suppliers can afford to take. Those who make investment decisions about broadcast TV have a lot to think about.

More pixels

The first and most obvious change Ultra High Definition brings is more pixels. The technological challenge to create this is simply that of adding bandwidth. HD requires 1.5Gbps, UHD 12Gbps. Most of the equipment needed to move signals around a studio or truck therefore has to deal with shifting 8 times the bandwidth of HD to make UHD work.

Whilst this is a simple problem to describe, it is technically difficult to achieve. The maximum bandwidth which most equipment can currently pass is 3Gbps, (Often abbreviated to 3G). This leaves manufacturers needing to use 4 x 3G circuits to create one UHD signal. This process, known as Square Division Quad Split (SDQS), is currently just about the only way to move "traditional" digital broadcast signals around a facility. There is another called 2 Sample Interleave (2SI) which is a different way of encoding the signal across the 4 circuits.

Both of these systems cost a lot compared to HD and present the challenge of dividing the signal into 4 and then combining it back again without error. This is currently the technology usually employed in live UHD production, as it's the one current leading manufacturers are best able to create. But no one thinks it is ideal, and everyone expects it to fizzle out pretty quickly. In the medium term the much discussed IP, (Internet Protocol) will kill this completely. And this relies on totally different equipment to the majority of current broadcast kit.

Techie Bit

Current HD television, (in much of the world), is broadcast in frames consisting of 1080x1920 pixels, at 25 Frames Per Second. This is sent in halves, or fields, every 50th of a second. A field is basically every other line of pixels in a frame. This is known as Interlaced, as a full frame never exists at any point in time and every other line is interlaced to form one frame from two fields. This standard is generally described as HD1080i50.

There are several UHD standards. The one now generally accepted to be the standard in TV broadcasting consists of frames of 2160x3840 pixels, sent as whole frames at 50FPS. This is known as Progressive, as a whole frame is sent every 50th of a second. This is usually written as UHD2160p50. (Incidentally, this is often referred to as 4k, which isn't quite true, as that is really a cinema format, but life is short and 4k sounds good.) Also incidentally, this equates to 8.3 megapixels per frame.

Each pixel comprises of a number of bits of information, the size of this information is known as the Bit Depth. Current broadcast standards have a Bit Depth of 10bits. Each pixel, whether UHD or HD, consists of the same amount of information regarding how bright it is and what colour it is. However...

Brighter, quicker, more colourful pixels

If the transition to UHD was only ever to be limited to adding more pixels, things would be relatively simple, and much the same challenge as the transition from SD to HD. However, UHD in this form is unlikely to set viewers on fire, as all it offers them is more pixels of the same quality, and therefore the ability to hang a bigger screen on their wall without things looking fuzzy.

What many stakeholders think will tip UHD into the mainstream will be better quality pixels, not just more of them. To achieve this will entail the adoption of extra features, such as High Dynamic Range, (HDR - which increases the contrast ratio from black to white), Wide Colour Gamut (WCG- which increases the colours available), and High Frame Rate (HFR- where more frames are transmitted every second). The first two of these features add complexity to the information carried in each pixel, (the bit depth) and present challenges in backwards compatibility to HD. The third (HFR) adds yet more bandwidth. If you transmit 100 frames per second, then bandwidth must double to 24Gps to cope.

HFR seems unlikely to become mainstream, as the bandwidth issues are tricky to overcome, but HDR and WCG are looking a firm bet. However, to add to the fun, there are some competing methodologies being proposed to make this happen. Things are moving along, but there is still work to be done before all stakeholders reach a consensus. All of which could redraw the challenges of UHD to some degree and could potentially make some equipment choices rapidly obsolete.

Techie Bit

Each pixel in an HD TV Picture contains information to describe it's brightness and colour. The data therein is read and processed by use of a Look Up Table (LUT), which contains the information required to convert this data to actual dots on the screen. In HD, this LUT is defined by the ITU-R Recommendation BT.709 (Rec 709). With UHD, HDR and WCG will mean each pixel will require a bit depth of 12 in order carry the extra information in it and a different LUT will be needed to convert that data to dots on the screen. There is added excitement here in that some manufacturers are stating that, with the use of some very clever maths, a bit depth of 10 can produce the same results.

All this is currently being defined under Rec 2020 and Rec 2100, and this is the rub, because this means that an HD rec709 LUT will not be able to read and translate the data in an HDR, WCG pixel without it first being transcoded. And that, it turns out, isn't straightforward. There's a lot of work going on here, with some competing thoughts on how best to achieve this. Notably from the BBC/NHK, who have developed Hybrid Log Gamma (HLG) and Dolby, who have Dolby Vision, which employs a technique called Perceptual Quantisation (PQ), as well as Sony, who have have their own S-log protocol. They are all extremely clever systems, with pro's and cons which can - and do - fill many tech articles right now. For the purposes of this paper, it's fair to say that it's likely that future TV sets, and professional equipment, will need to be able to cope with more than one of these standards.

More loudspeakers, more choice

Meanwhile, the world of audio has seized the UHD "moment" to attempt to offer innovations in how we listen to TV. Next Generation Audio (NGA) is a relatively broad term defining new ways to add more speakers, notably in the form of Dolby Atmos. But more than that, so called "Object Audio" gives programme makers the ability to offer viewers the chance to choose they audio they want to hear. For example, the age old debate about how loud commentary should be compared to crowd FX in a football broadcast, or dialogue to music in a drama, can be left in the viewers hands. More than that, alternative languages, (or commentators) can be seamlessly integrated into your soundtrack. Provided, of course, the viewer has the latest equipment and a clue how to use it.

More screens

We are all familiar with what is currently called Second Screen, as programme makers and broadcasters find new ways to reach their audiences and bring eyeballs to their first screen offerings. Its clear that this will become the primary route to gain and retain audiences for pretty much everything in future. Producers and broadcasters who are not all over this will probably start running out of viewers pretty quickly. But more than Second Screen, multi-screen experiences, where viewers watch their TV whilst interacting using a phone or tablet, are catching on quickly too.

Currently, much of this work is done in technological and production silos, with broadcast and internet talent often totally separated. This won't last. Part of the reason it won't last is due to the technology which is, in some cases already here, and in others, very much on its way. The possibilities for programme makers to synergise are really opening up here. Systems such as EVS C-Cast are a good example of what is currently possible.

IP

Earlier, we discussed the challenges of moving "traditional" broadcast signals around a facility in UHD. Well, the internet moves data around pretty well these days, and its no surprise that this technology will form the basis of all TV production someday soon. However, as ever, there are hurdles to jump. Many of the routers and switches which connect us to the information super-highway are built on an infrastucture of up to 10Gbps per connection. You will remember that a UHD signal is 12Gbps. Uh oh.... Yes, this therefore involves compression to squeeze 12 into 10 - and compressing a signal takes time and introduces complexity.

Yet it has been done. In the UK, Arena TV are already operating their OBX, the worlds first significant IP-based production truck. And it works. There are advantages in using this technology as the backbone of your facility. Much of the core kit is tried and tested computer equipment, which is available off the shelf. There are people out there who are well versed in its operation, such as Videlio, who system integrated OBX for Arena.

However, all you have to do in TV is wait a minute, and another technology comes along. And so, right now, its just about possible to build an IP infrastructure based on a 100Gbps infrastucture, removing the need to compress those 12G signals. And that's exactly what Timeline TV have recently announced that they are doing, with a new large production truck based on this technology, currently under construction.

Convergence

Perhaps the most important aspect of the introduction of IP in broadcast workflows, is the convergence of skills and equipment it facilitates. When you look at machines such as the NewTek Tricaster TC1, they offer a range of capabilities undreamed of in traditional broadcast technology until recently. I posit that it won't be long before this one-box type of technical solution, or at least a descendant of it, will be available to those building the largest scale production resources; no doubt in the form of scalable blocks. But who will build it? And when? Traditional market leaders such as Sony and Grass Valley will no doubt want to be there, but there could well be disruption from manufacturers who are not approaching from a professional broadcasting background.

And there's more. Several technologies are migrating from computing to broadcasting. Notably Augmented Reality (AR) and Virtual Reality (VR). Which are enabling first, second and gaming, (or third screen) to come together in ways that are revolutionising viewer engagement. A great example being the award winning offering of FIA Formula E from Aurora Media Worldwide and Little Dot Studios.

So now what?

So what, apart from massive expenditure and a lot of room for doubt, does all this offer programme makers? In a very few years time, I have no doubt that our technology landscape will have changed very significantly. Facilities suppliers rarely get to choose when they need to invest in the next generation of technology, and have to contend with investment cycles which mean a miss-step now could leave them seriously disadvantaged in a very short time. Programme makers are rightly feeling the need to embrace and exploit all the tools that are rapidly becoming available. The skill-sets required to create for second screen, OTT, linear TV and social media are all converging, and there's a need to choose suppliers who understand this, and can facilitate it.

I think it's fair to say that things have never moved faster than they are doing today. Scrupulous research and clear thinking are required to ensure that the technology your programme making relies upon is as future-proofed and cost-effective as possible. The possibilities have never been more diverse or exciting.

Simon Bowler - TX98

TX98 consults with businesses to help them plan for the future, and make sure they thrive in it. Sometimes with know how, sometimes with "management bandwidth", often with both. coming up, I have an interesting schedule at NAB, where I wll be engaging with those who are defining the technology we will be using in the future and reporting back to clients who need to know. If you are in need of some additional management resources to ensure you stay on top of the game then please get in touch, to see how I can help.

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