4K Video – Is 1080p Good Enough, Applying 4K Video in the Real World

4K Video – For Those Who Think HD isn’t Enough

Just a few short years ago HDTV hit the market. It was to be the new standard format for both broadcast television and video recording, with our movies arriving on Blu-Ray, to replace the venerable DVD. Many thought that television had reached its maturity and that we were now in an era of ultimate resolution. After all, why would anyone need more than 1920 x 1080 pixels of resolution to see all the detail in a video image?

 

Well, what we thought was the peak of the mountain truly wasn’t; it was merely an intermediate step on our way up to new heights. While HDTV provides incredible image sharpness, everyone knows that it isn’t “perfect.” Perfection, that amazingly slippery animal, is impossible to reach.

 

Even so, it’s just a matter of time before the “high resolution” of our HDTV sets is considered with the same contempt that we offer to the old broadcast standard today. 4K video provides four times the resolution of the 1080p “Full HD” resolution that we’ve become accustomed to. While not abounding in the marketplace, you can be sure that 4K video will overcome HDTV in another few years.

 

To make the difference understandable, it helps to visually compare the relative size of 1080p and 4K. As you can see from this image, 4K (shown in red) provides four times the viewing area that 1080p (shown in light green) does. That’s the same type of jump in image resolution that we saw when 720p HD (shown in dark green) was introduced in the marketplace, replacing the 640 x 420 resolution on our DVDs (shown in light blue).


4k resolution compared to 2K  1080p 720p DVD   

 

Image courtesy of Wikimedia Commons.
This image is licensed under the Creative Commons Attribution-Share Alike 3.0

 

4K video is named as such because the horizontal resolution of the image is a nominal 4000 pixels. As you can see from the image, that 4K is actually 3840 pixels. By comparison the name for 1080p comes from the vertical resolution of the image being 1080 pixels and 720p comes from the vertical resolution of the image being 720 pixels. Since 1080p has a horizontal resolution in a 16:9 aspect ratio of 1920 pixels, 4k video gives an image that is a touch over twice as high and twice as wide; with a total area that is four times that of 1080p (8,294,000 pixels versus 1,036,800 pixels). Another way to put it is that 1080p is roughly a 2K image, compared to a 4K image.

 

There are actually several different 4K video resolutions and formats, each of which has been developed for a particular purpose. As of yet, there is no fully defined consumer specification for 4K video in home theatre equipment, although one is in process.

 

Format

Resolution

Aspect Ratio

Pixels

4K Ultra high definition television

3840 x 2160

7.78:1 (16:9)

8,294,400

Digital Cinema Initiatives 4K (native)

4096 x 2160

1.90:1 (256:135)

8,847,360

DCI 4K CinemaScope (cropped)

4096 x 1714

2.39:1

7,020,544

DCI 4K Flat (cropped)

3996 x 2160

1.85:1

8,631,360

Academy 4K (storage format)

3656 x 2664

1.37:1

9,739,584

Full Aperture 4K (storage format)

4096 x 3112

1.32:1

12,746,752


As we compare the various formats and their resolution, we see that the horizontal resolution doesn’t change much between these various 4K formats, but the vertical resolution does. This is because the guiding definition of 4K video is based upon the horizontal resolution. Adjustments in aspect ratio require changes to the vertical resolution, so that the horizontal resolution can remain consistent.

 

While some 4K video equipment does exist and is being sold, it really hasn’t swept the marketplace yet. The major reason for this is cost. Just as HD equipment was extremely expensive when it first hit the market, 4K is as well, although even more so. Currently, there are 4K video cameras available, as well as monitors and televisions. There are even a couple of smartphones which have 4K video capability. We can see from this, that 4K will shortly be taking over the market.

 

Another interesting thing that the diagram above shows is that there is already contemplation for a 6K video format, which will be half again larger than the 4K resolution. Considering that 4K hasn’t exactly swept the market yet, this can be seen as ambitious. Nevertheless, this shows us that the future of video is higher and higher resolution, with nobody knowing when the practical limit will be reached.

 

Applying 4K Video in the Real World

One of the problems that consumers face is when to make the switch over to 4K, just as we had to face that same problem with HD. If anything, the problem will be even greater, as home entertainment systems are more extensive today than they were ten years ago.

 

As I’ve already mentioned, there is no 4K standard yet for home theatre; nor is there a standard recording format for movies and other videos that is intended for home use. Therefore, anyone buying a 4K television or monitor is going to be somewhat limited in their ability to use it. The only consumer video that is readily available in 4K is via YouTube.

 

When 4K more fully saturates the marketplace, most people will end up changing their system over piecemeal, with a mixture of HD and 4K equipment, up until they can afford to replace everything in their home entertainment system. This will be somewhat frustrating for the people involved, as they won’t see the full benefit of their purchase, until they have enough equipment that is 4K to provide a full video experience.

 

 

When HD and 4K equipment is connected together (which can be done) the actual resolution viewed is that of HD and not of 4K. That means that a 4K television with a Blu-Ray player connected to it have to upscale the image, displaying each pixel of information provided by the Blu-Ray will be displayed on 9 pixels on the 4K television. If they didn’t do this, then the Blu-Ray image would play only on a quarter of the screen, leaving the rest black.  

Rich Murphy