HD and Beyond: What the 4K? Part 1
By David Meyer, Kordz.
4K is an exciting and necessary development in the world of electronic displays. Unlike 3D which is really just...
By David Meyer, Kordz.
4K is an exciting and necessary development in the world of electronic displays. Unlike 3D which is really just a novel side-step feature, 4K defines a whole new level of detail and immersive realism on the screen. But it's still early days and the industry is generally still on a learning curve.
As a member of both CEA's 4K Working Group, and CEDIA's Technology Working Group as HDMI Subject Matter Expert and co-author of their 4K white papers, I regularly get asked a whole lot of questions on the topic, such as:
In this two-part series, I will answer these questions, and cover some additional areas along the way.
Why Do We Need 4K?
The answer to this question is actually quite logical. Screen sizes have got a whole lot bigger on average over the last several years, but viewing distances have generally not increased. There was a time when we thought that a 34" (CRT) TV was massive, and when flatpanel displays came along, 42" became the norm. These days 55-60" is common for general living rooms, and there is a growing catalogue of even larger sizes from the big CE brands.
As screen sizes get bigger without changing resolution or viewing distance, the pixels too become relatively larger. There comes a tipping point where our own visual acuity may exceed the display's pixel density, meaning an effective loss of perceived resolution.
Now give some thought to IMAX, which employs a massive screen and the audience sitting relatively close. Achieving this high-quality immersive experience is made possible with the use of a much larger film cell than is the case in a classic 35mm cinema. 4K delivers the same effect in the home, enabling larger screens with relatively close viewing distances.
[caption id="attachment_5319" align="aligncenter" width="438"] 70mm IMAX film cell compared with traditional 35mm film cell.[/caption]
There is another consideration, namely the marked increase in resolution of the other devices we typically use every day. 1080p was regarded as remarkable back in 2005 but is, after all, only 2 megapixels (1920 x 1080 = 2,073,600). Let's face it, these days you would turn your nose up at a 2MP camera in a phone! By comparison, 4K offers a far more contemporary 8.3MP. Enough said.
What's the Difference Between 4K and Ultra-HD?
Nothing. Let me explain. The name '4K' was derived from the commercial D-cinema space, being a SMPTE-defined standard for a 4096-pixel horizontal resolution (Hres) image. This evolved from 2K before it, being 2048 pixels wide. Display hardware needs physical pixels, so commercial 4K display devices such as DLP projectors, employ 2160 vertical pixels (Vres), while 2K is 1080 Vres - the latter being the same as for consumer 1080p.
In 2009 HDMI Licensing announced the HDMI 1.4 specification which first defined 4K formats for broader use, including consumer, with HDMI as the transport. This included two formats:
Three years later in 2012, the CEA, via its 4K Working Group, targeted a consumer-friendly moniker for this new format, as evolution from Full-HD (1080p). Ultra-HD was the result, and is in fact interchangeable with the term 4K or 2160p. Same thing.
For the record, expect to see the 3840 Hres version dominate, as it retains the same standardised aspect ratio of 16:9 or 1.78:1 as does 720p and 1080p. 4096 may be offered in some high-end product only, as is the case with Sony's flagship VPL-VW1100ES projector.
[caption id="attachment_5321" align="aligncenter" width="600"] The Sony VPL-VW1100ES projector supports 4096 x 2160 pixels.[/caption]
What About Content?
It is valid at this point to reference the age-old dilemma of which came first - the chicken or the egg? Think back to the early days of 1080p. Do you remember that? The first few generations of devices comprised only upscaling DVD players and the occasional AVR doing the same. Arguably, none did it well, as superior images did not result, only increased bandwidth demands on a not-yet-matured HDMI. It took until about 2006 when HD-DVD and Blu-ray came along with native 1080p content, finally giving way to Blu-ray as victor in 2008.
That is now so long ago that we seem to have conveniently forgotten that step which is necessary in evolving a new format. With 4K, we get to do it all over again, but expect it all to happen a whole lot faster. For one thing, 4K actually has a head start on where 1080p was at the same point in its infancy, as there already exists an impressive back-catalogue of titles, both through rescanning/mastering and also native capture, i.e. movies being shot in 4K. All we're now waiting on is at least one ratified source platform.
[caption id="attachment_5320" align="aligncenter" width="530"] Shooting of 4K content is already widespread.[/caption]
The Blu-ray Disc Association (BDA) is already working on the next version of the BD specification. This is rumoured to be quite lateral in its approach, paving the way for inevitable development of both 4K High Frame Rate (HFR) and even 8K formats. It clearly does not want to have to come back and redo it all over again in a couple of years! Stay tuned.
When questioning if there's any point to 4K without content availability, consider that content providers would not release titles unless there were displays available to support it. The displays must come first, followed by source devices, concurrent with content. The first steps are already well advanced, with an impressive offering to market at typical early-adopter prices. They will inevitably come way down.
4K is a logical evolution in HD video, finally offering a serious upgrade path from the long-matured 1080p. 2MP just doesn't quite cut it anymore, particularly as TVs have become progressively larger, making screen size/viewing distance ratios smaller. 4K, in conjunction with evolving display technologies such as OLED, is the answer to our growing demands for size and quality.
In part 2 next month, we'll look at the issues surrounding 4K and HDMI.
David Meyer is the Founder and Managing Director of Kordz, specialist in reliable long-reach HDMI. Following the launch of HDMI 2.0 at IFA in Berlin in September 2013, Kordz became the first approved HDMI 2.0 Adopter in the world, outside of the HDMI Forum.
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