The most familiar is the strangest! Do you really know these video interfaces?

Speaking of the video interface, many people can say a little bit. Isn't it HDMI, DP, VGA, DVI? What else can be new? In fact, the most familiar is often the strangest. Today, I will tell you about these three interfaces.





VGA interface

The VGA interface is an old face. This video interface, invented in 1987, still exists in many devices. Including some standard notebooks (except ultra-thin notebooks and tablet notebooks), and even most desktop graphics cards (including core graphics cards), are still equipped with a VGA interface.

VGA outputs and transmits analog signals, but the graphics produced by the graphics card are actually digital signals, and the monitors also use digital signals. Therefore, the video interface using VGA is equivalent to undergoing a digital-to-analog conversion and an analog-to-digital conversion, which also means that it is easily interfered, and signal conversion is also prone to signal loss. The result is that the picture is easy to be missing.

In theory, the maximum resolution that VGA can support is 2048×1536@60Hz, but in actual use, the maximum output capacity of the general VGA interface is 1080P resolution, which is out of date by comparison.


That being the case, why is VGA still widely available on various devices? The reason is actually super simple-in order to ensure maximum compatibility.




DVI interface

The DVI interface is an interface standard introduced in 1999. The transmission signal of the DVI interface adopts an all-digital format, with a variety of specifications, and is divided into 5 standards. Among them, DVI-D and DVI-I are divided into two types: "dual channel" and "single channel".

The two types of DVI are 25-pin and 29-pin, as shown in the figure below. Intuitively, there is no difference between the two interfaces. The DVI interface transmits digital signals, which can transmit high-resolution video signals. No conversion occurs when DVI is connected to the computer graphics card and the monitor, so there is no loss of signal.



However, due to some shortcomings, a better interface technology that can meet the development of the high-definition video industry in the future is needed. It is for these reasons that the HDMI standard was born.



HDMI interface


HDMI is a digital interface. Since all analog connections (such as component video or S-video) require no loss when converting from analog to digital, it can provide the best video quality. This difference is particularly noticeable at higher resolutions, such as 1080p. Digital video will be clearer than component video, eliminating the softness and smearing found in component video. Small, high-contrast details such as text make this difference to the extreme. In addition, there are many reasons why the HDMI interface is widely used. This also extends the HDMI interface of various sizes, mainly Micro, mini HDMI and standard HDMI interfaces.