At Vistek, we’re fortunate to have employees with a tremendous amount of insight and experience with our products. When it comes to video, having the right answers is the only way to make an informed decision on equipment, settings and so on.
That’s why it’s our pleasure to introduce an all new column here at the Blog. Brian Young will be discussing the issues and questions he comes across as a seasoned video professional. A noted speaker, trainer, presenter and panellist, Brian is also a long standing member of SMPTE and CICA. Brian has delivered numerous technology papers to CCBE, WABE & CSC, to name a few.
Brian is dynamic presenter who provides a unique mix of technical savvy along with practical hands-on production experience, combined with his over 25 years of business expertise. He is highly regarded in the areas of Acquisition Products and Post Production, and has been instrumental in the introduction of a broad range of High Definition products to Canada.
We’re kicking things off with his take on perhaps the biggest issue in video today: 4K technology.
Unless you have been under a rock for the past year, you know that digital cinema, video and consumer electronics in general are moving towards adopting the much talked-about 4K or UHD (ultra high definition) tech. Major players like Sony have publicly stating that they are “unifying Sony though Ultra HD” meaning they feel that UHD will become a driving technological force across multiple platforms.
This year, the buzz coming out of CES was overwhelming as almost everyone was talking about 4K, showing off new TVs, cameras, laptops, mobile devices, streaming media services and more – all containing 4K or UHD technology.
And yes, there’s a ton of spin out there at the moment about 4K or UHD TV – both pro and con. Many people have asked me how to steer through all this noise and make the right decisions when it comes to making equipment purchases for today and tomorrow. And so in this ongoing series of articles and updates I hope to explore the various aspects of transitioning to a 4K/ UHD world.
This transition is similar to the move from HD from SD, in that 4K is going to usher in substantial change. And since we all fear change to some degree, we’ll see our share of misinformation. Naturally, it’ll take some time (these things don’t happen overnight) but things will change – and probably faster than we expect. That’s why being prepared is in all our best interests.
I once read an article that referred to the latter half of the 20th century as “the lost 50 years”. It stated that, while it was one of the most explosive periods for recorded visual media, the quality of that archive is so poor that in many cases it’s either lost altogether or virtually unwatchable / unusable. That’s a fact that many documentary film makers now attest to. This is to say that SD footage simply does not stand up visually by today’s standards.Much of our visual media from the pre-digital/HD days may appear to be lesser in quantity, but is often superior, as it’s derrived from 35mm or 16mm film, which is actually accepted in digital resolution as being approximately 4K.
The move to 4K is not so much about change as it about the acquisition of images in a manner that best preserves them – making them timeless in quality and ultimately producing a better archive. 4K guarantees superior quality images today, along with an ideal preservation for tomorrow.
4K Myth #1:
The visual change is too slight, or not substantial enough a change from HD and therefore unnoticeable.
The fact is, 4K/UHD images can be literally 4x the resolution of today’s 2K or HD images – something that is quickly apparent to even the most non technical among us. Images pop off the screen, providing a clarity and depth of image that is instantly more engaging. Many have remarked that 4K resolution looks 3D in nature, with a massive difference in color depth. That’s all thanks to their enhanced sharpness and signal resolution.
4K Myth #2
4K requires large displays to see any apparent benefit
To answer that, let’s make a comparison: Retina display on an iPhone is better than anything that came before it and are easier to view and read. In that same notion, 4K-quality have already arrived on mobile devices, as multiple brands previewed this technology just weeks ago at CES. So, with 4K quality already rolling out on numerous mobile devices, clearly display size is irrelevant. In fact, several brands at CES even demo’d mobile devices capable of both wirelessly receiving and displaying 4K/UHD video.
4K Myth #3
The cost of adopting 4K is totally overwhelming
Today’s latest laptops, desktops and pro machines already work to process these high quality files. And as far as storage is concerned, the cost per minute of storing high quality 4K or UHD files is now significantly less than when we first started working with file-based SD video. And on the camera side, 4K capability is becoming rapidly widespread and more affordable. New codecs are being introduced that enable 4K recording and transmission using just a small premium in bandwidth over what we already use today for HD. What all that means is that ultimately, you’ll be getting 4K quality with minor or negligible differences in cost.
To truly understand why 4K is worth embracing, we’ll need a proper understanding of what 4K is.
UHD (or ultra HD) is a ubiquitous term used to describe image resolutions beyond Full HD (>1920×1080). Originally, there were two specifications for HD images or HD broadcast standards. One that had a lower spatial resolution (pixel count) but generally could provide a higher temporal resolution (frame rate) of 1280×720 (pixels) up 60P (frames). Then there was the broader adopted standard of Full HD that had a higher spatial resolution, but generally lower temporal resolution of 1920×1080 60i where the 60i stands for interlaced fields, so the frame count was actually 30fps or 29.97. Many professionals chose to shoot at 24fps (or technically 23.98) to mimic film style image judder while sacrificing temporal resolution, which complicated matters. It is also important to note that the transition from CRT displays to flat panel during the HD adoption period essentially eliminated the need for 60i interlace signals.
Most of today’s HDTV’s and cameras can accommodate up to 1920×1080 60P signals, but broadcast cannot support that frame rate as it’d require twice the available bandwidth. In other words, two channels would be required – not what providers or subscribers want to hear in today’s multichannel universe. However Blu-rays and playback files are available in full 1920 x1080 60P via HDMI 1.4, so most compatible HD displays do play 60P images.
1920X1080 HD is about 6x the pixels or spatial resolution of 640×480 which was the resolution of SD standard definition NTSC television. Due to the 1280×720 or 1920×1080 pixel count, HD signals are considered to be wide aspect, defined as being natively 16×9 in aspect ratio whether they are 720 or 1080 in nature where SD was a 4×3 (more square) aspect ratio. Since cinema screens have wider aspect ratios than televisions the 2K cinema DCP (Digital cinema projection) standard identified an aspect ratio of 17×9 or 2048 horizontal pixels by 1080 vertical pixels. Since both HD and true 2K have an horizontal pixel count near 2,000 pixels they are often generalized together as being 2K resolution.
Does that mean that 4K twice 2K?
4K is generalized to encompass two standards: one for cinema and one for television. True cinema 4K has horizontal resolution of 4096×2160 with a horizontal pixel count of just over 4,000 pixels hence the categorization as 4K and hat delivers a 17×9 aspect ratio. The vast majority of consumer and pro displays and cameras cannot actually support this cinema 4K resolution. Instead they work at a resolution that is 4x or quad HD also known as QFHD (quad full high definition) at 3840×2160 pixels delivering exactly 4x HD in spatial resolution, with the same 16×9 aspect ratio. So in essence both can deliver the same image resolution to a given part of the screen, QFHD is simply slightly cropped from 17×9 to 16×9 image size the same as 2K and HD.
Within cinema 4K or QFHD you can now also have the choice of varying progressive (no longer interlace) frame rates up to and even beyond 60P, for example True cinema 4k products might also be able to now support true 24P, where QFHD products are more likely to support the 23.98 video standard. HFR (high frame rate) beyond 60 fps might also be supported in some cases, although as I’m sure you can appreciate processing and storing this type of bandwidth is on the extreme side and so is offered at quite a premium price point if at all.
4K can produce a better HD signal than can be natively produced in HD itself.
This level of “4K” or UHD video resolution when compared against say digital photo’s, means that we are actually capturing over an 8 megapixel image per frame. Which is quite significant as an 8 megapixel image can actually produce a very good quality 8×12” print. So imagine the possibilities of a still camera with a motor drive capable of capturing 60 frames per second.
4K video could in fact allow you to produce images for any medium print, web, video in a single pass.
Another thing to note is color sampling. Just as in SD or HD you can reduce the amount of information you want to store or transmit overall by reducing the color space from 4 2 2 to 4 2 0. Those options are also available in 4K, or even options for a full raw recording within 4K. But remember, with 4K you already have 4x the pixel count which means even a 4 2 0 a 4K signal can produce an excellent down converted 4 2 2 HD signal. In fact, 4K can produce a better HD signal than can be natively produced in HD itself.
Most early adopters of HD in fact were just looking for ways to improve their SD deliverables (while sometimes unknowingly also improving their archive footage) something that just as easily applies today as the 4K era dawns, now that the HD transition is essentially complete, we are looking to delivering and preserving even higher quality images that can engage more viewers.