Over the last few years, more and more TV manufacturers have been pushing us into purchasing their latest and greatest buzzword, 4K or UHD. However, there is a massive amount of confusion around the subject. This article aims to demystify some of these areas.
There is a minefield of technicalities and jargon around this area, so beware. This article will attempt to explain these as simply and completely as possible. If it's a bit overwhelming, don't hesitate to get in contact, we're generally very happy to talk about TV's and Display's in general.
With the release of a confirmed 4K Blu-Ray Format and a few other recent announcements, we're now very sure of what TV's will actually be able to play 4K content and which will not.
This article will cover:
- What is 4K?
- Will my TV actually play 4K?
- 4K Blu-Ray
- Chroma Subsampling
- Other 4K Sources
- 4K over longer lengths
What is 4K?
4K refers to the resolution of a video image, which should theoretically mean an image over 4000 pixels wide. Even the name has been confused by the marketing guru's to mean something completely different from it's technical definition.
In the context of consumer grade equipment it actually means Ultra High Definition TV (UHD-TV), which is a resolution of 3840×2160 pixels.
This higher resolution (all other things being equal) should make your images far clearer, especially on larger screen sizes. There are a lot of other factors that go into image quality, so it doesn't necessarily guarantee any particular level of picture quality.
Will my TV actually play 4K?
This is actually very tricky. Although many TV's are capable of physically displaying UHD resolutions, most TV's and home theater receivers may not get the full benefit of the latest standards. Because the latest standard include better colour depth, greater copyright protections, more frame rates and higher dynamic range, not all TV's sold as UHD ready will actually work fully and make the most of the very high quality source that UHD Blu-ray will be.
It's not exactly clear whether TV's with UHD resolution and HDMI1.4 based connections will actually work with UHD Blu-Ray players, although it seems they may have to reduce the resolution to be able to play happily.
4K Blu-Ray is the recent released standard for disc based video playback.
It standardises a number of features which should greatly increase picture and sound quality in a wide number of systems.
All of the new features require much higher bandwidth than existing Blu-Ray media, meaning that many aspects of the playback chain will need to upgraded in many systems.In many cases, for the full benefit, every device in the playback chain will need to be HDCP2.2 compliant.
Basically it all boils down to:
- Higher Resolution
- Greater potential dynamic range
- More Accurate Colour
- More Sound Channels
- Higher Bandwidth Requirements (from 10.2Gbps to 18Gbps)
- More stringent copyright protections
HDMI2.0 is the connector and standard designed to enable all of this magic to happen. It mostly only refers to the connectors and chipsets in your physical devices. The cable and plugs etc. are essentially unchanged from the older 1.4 standards.
Technically any cable that meets the older high speed (category 2) should be fine for the latest standards. However it's worth noting that many of the cheaper cables that claimed to meet this standard, but actually don't, may not work perfectly. Because the bandwidth requirements are so much higher, many existing cables may have intermittent performance or not work at all. In these cases you may need a new cable.
HDCP (High Bandwidth Digital Copyright Protection) is designed to make sure you cant directly record UHD programs and to make sure cabled connections are secure in this way.
The way it operates is to be in constant contact using secure keys with the display (sink device) to ensure that it is actually playing back the material. If the device doesn't respond correctly within 20ms, the stream will stop.
This content protection is actually very troublesome for a lot of consumers as it complicates the whole process and creates issues where they needn't exist. It also makes HDMI extension products far more costly and difficult to produce.
Basically every device in the chain must support HDCP2.2 to get the best out of the latest standards.
HDR (High Dynamic Range) is one of the most exciting new developments to come with the 4K Blu-Ray standards. Perceived Contrast is the single most important factor in image quality, so this is very exciting to those of us who care about picture quality.
Basically it lays the path for more realistic images by allowing a greater difference between the brightest shades and darkest shades displayed.
Chroma Subsampling 4:4:4 vs 4:2:0
This deserves it's own article, but put very simply relates to the way video displays compress colours. Not all devices will be capable of displaying the full uncompressed beauty of 4:4:4, and it may not always be ovious from a devices specifications whether it will limit this at all.
Other 4K Sources
UHD Blu-Ray isn't going to be the only way to watch UHD video. Streaming services and broadcast TV will all start to jump on the bandwagon as well.
However, all indications are that to keep the data rates down (and preserve your internet connection) these streams will still be heavily compressed. Image quality tests have consistently shown that current 1080P Blu-Ray's look far better to most people than a UHD Netflix or Youtube stream.
4K Over Longer Lengths
Many people have their equipment hidden away, or distribute video sources around their house over baluns and network cables. Because of the much higher bandwidths involved, this is much more difficult with 4K sources.
Products are only now coming onto the market that support this correctly, but for almost all of them, the supported lengths are much shorter at any given price points. Partly this is due to the inherent limitations of Cat6 Network cable for most people.
Custom Installers are now highly recommended to run shielded CAT6 Cable or dual runs of CAT6 in any location where UHD video is crucial.
There's a lot to think about when it comes to 4k, and because it is such new technology, there is a lot of confusion around. If you're at all unsure about what you should be doing, find a professional to help. Custom Installers deal with these issues day in, day out and have will be able to point you in the correct direction.