Welcome to another article in the series of articles on resolutions. For today I have more information about screen sizes and resolutions, this time we will focus on the descriptions of the terms: HD (720p), Full HD (1080p) and 4K (UHD or 2160p)
HD Resolution (720p)
The HD High Definition (High Definition) refers to the resolution of 1280 x 720 pixels, which in turn combines with widescreen (16: 9) screens. In general, images that respect this resolution have a very satisfactory quality. HD has, in fact, become a benchmark in the market, and can be found in low-cost and intermediate TVs, as well as smartphones and tablets. You just need to be careful not to confuse it with its two variations: the nHD, which has 640 x 360 pixels and the qHD, which has 960 x 540 pixels.
720p and 720i
Another factor that resulted in HD resolution is the default HDTV (High-Definition Television or High Definition TV), which determines a set of parameters to replace traditional television systems such as NTSC and PAL. Among these criteria is the association of the resolution of 1280 x 720 pixels with the aspect ratio of 16: 9.
At this point, you may have already understood: the term 720p, which is widely used, is also a name that indicates the HD resolution, that is, 1280 x 720 pixels. But, where did that letter 'p' come from?
Human eyes do not notice, but TV content is updated several times per second. This process is called Refresh Rate or Update Rate and is normally measured in Hz (Hertz). A 60 Hz TV, for example, renews its images 60 times per second. Theoretically, the higher this number, the more “comfortable” the image is displayed on the screen.
This is where the 'p' comes from. The letter refers to the technique of Progressive Scan (Progressive Scan), which is also one of the parameters of the HDTV. The term indicates that the screen update happens in all the lines of this, from top to bottom, that is, all the content displayed is renewed in one step only.
It may seem somewhat obvious, but it is that older TV systems use the Interlaced Scan(Interlaced Scan), where the update takes place in a similar way, but first the even lines are updated, then the odd lines, in a “line yes, no line” scheme.
Interlaced scan: first one group of lines, then the other
The Interlaced Scan is represented by the letter 'i', so there may also be a standard 720. But, there is no record of official use of that term, even because the current technology supports 720p even on the simplest devices, with no reason for adopting the interlaced mode. It is worth noting that standards that do not reach HDTV specifications tend to fit the characteristics of the SDTV (Standard-Definition TeleVision). Its most common resolutions are 704 (or 720) x 576 pixels and 704 (or 720) x 480 pixels.
Full HD Resolution (1080p)
If HD already results in very good images, the Full HD appears to offer an even more satisfying experience. The term, which can also be abbreviated as FHD, represents the resolution of 1920 x 1080 pixels, equally (or more) appropriate to the 16: 9 ratio.
Like HD, Full HD gained strong commercial appeal, something like “HD is good, but Full HD is even better”. A little more sophisticated equipment is the target of this type of screen, as is the case of the Samsung Galaxy S5 and Google Nexus 5 smartphones, in addition to monitors and TVs of various sizes, of course.
Full HD TV from 40 inches (Original Image by Samsung)
4K Resolution (UHD or 2160p)
We are still enjoying our Full HD devices, but the industry wasted no time and has already made a higher standard a reality - four times higher, actually: 4K resolution, which represents the combination of 3840 and 2160 pixels.
TV 4K of the line Bravia (Image by Sony)
Also called Ultra HD (UHD), 4K resolution started to be developed in 2003, being used in mid-2006 by the cinema. A few years later, however, it was already possible to find UHD screens on more sophisticated televisions that “cost a lot of dollars”.
It is very difficult to find an 4K TV that is less than 50 inches in size. The reason is that, at least until now, only larger equipment can combine technical viability of construction and significantly superior image quality.
As with all other standards, the 4K resolution also has its variations. The combination of 3840 x 2160 pixels is taken with the main one because it is the resolution in the specs of the Ultra HD Television, Also known as UHDTV. Thus, we can also use a denomination that refers to vertical measurement with Progressive Scan: 2160p. However, unlike the terms 720p and 1080p, the name 2160p is not widely used.
Another resolution that is also represented by the acronym 4K (but not by UHDTV) is that of 4096 x 2160 pixels, which was officially adopted by Digital Cinema Initiatives (DCI), an entity formed by major companies in the film industry to determine standards for the segment.
The assembly below gives a good idea of the “generosity” of Ultra HD resolution:
VGA versus Full HD x 4K
Why the letter 'K' in 4K?
Like HD and Full HD, the term 4K not only refers to a resolution but also has a strong commercial appeal. But, if the standard can also be called Ultra HD or UHD, why is 4K the most used expression? It turns out that the letter 'K', in the English language, is commonly used to represent the number thousand. So, if you have 2 or 3 units of anything, you can call this amount 2K or 3K, for example.
As the horizontal resolution of the UHDTV is a number that approaches 4000 (and surpasses it, in the case of DCI), it is assumed that the acronym 4K has come to be used to represent it because it conveys a clearer notion of its grandeur.
Here, it is worth noting that the existence of 4K does not mean that HD and Full HD will be delegated to the past, at least not for a long time. These standards have satisfactory quality in cell phones, tablets and even televisions. In addition, 4K has some disadvantages. To begin with, the amount of content in this format is still small, although there are already films, broadcasts of sporting events and even UHD support on services like YouTube.
Another possible drawback is that 4K transmissions require fairly fast Internet connections, which is not yet true for many people, even in developed countries.
Today was a little long, but as my friend HOUSE says - “whoever has information has power”.
Until now with more news.
