With so many manufacturers pushing the latest and greatest in 4k or ultra HD, it can quite confusing on what it actually is. 4k technology is generally referred to as 4x times the quality of Full HD or 4x 1080p. Simple right….unfortunately not..
There are 3 things that make up picture quality. The first of these are the number of pixels. So having 4x the amount of pixels is a good start.
The second of these is the frame rate or hertz. This is the number of frames per second, so the higher the frame rate the smoother the picture quality.
Finally the colour sampling or chroma sub sampling is the final component that makes up the picture quality. This refers to the amount of true colour shown on screen at one time. Unsampled colour is referred to as 4:4:4 while it is often sampled at 4:2:2. This reduces the bandwidth required by a third without effecting the visual quality of the image.
So, now that we know what makes a high quality image, how do we get all of on the screen. Easier said than done.
Display port is capable of carrying 4k at 60 fames per second with a colour sampling of 4:4:4. As is HDMI 2.0, which has taken over from HDMI 1.4 as the new standard of HDMI as of 2014. So unless you have a source device with a DisplayPort output or HDMI2.0 chipset you will end up with 4k at 24-30 FPS. This will greatly reduce the quality of the image and a better picture would be achieved at 1080p instead of 4k.
So we have the cable and we have the TV’s that can produce a 4k image. The problem comes in when you try to switch 4k video. Currently there is little or no way of switching true 4k due to the large bandwidth required. Many of the switchers use colour sampling of 4:0:0 to reduce the bandwidth. This becomes noticeable especially on the larger 4k screens.
The other factor and probably the most important component that currently posses a major roadblock to the success of 4k is content. With no standards set for a 4k video player currently on the market and with HD TV currently being broadcast at only 720p it is hard to see 4k being available to every household. There also remains the fact that there is very little content out there recorded in 4k
On the other hand streaming services such as Netflix are starting to release content in 4k as a premium service. Using Netflix as a native application built into the display eliminates the transmission issues inherent with 4k. On the downside it is recommend to have a 25mb/sec broadband speed and unlimited data allowance to watch 4k.
While there are a number of issues currently stopping 4k from being readily available, there is no doubt that the incredible picture quality offered by 4k means it is here to stay unlike 3D which proved to be little more than a gimmick.
Ciarán McGrath, Audio Visual Consultant (Digicom)