Signals input Tips
With the development of displays, it has more and more interfaces. In this case, many people are more and more confused about what interfaces of the display are used. Even the friends who often pay attention to IT are the same.
To this end, it is necessary to perform a comprehensive analysis of the interfaces used in the current display. At present, there are many interfaces involved in the display, among which VGA, DVI, HDMI, USB, DP, etc. are mainly used. Some of these interfaces are also divided into different types and versions. In this picture analysis, it will be introduced and analyzed in detail.
VGA interface
The VGA interface is one of our common interfaces, and has been adopted since the CRT era. It is a color difference analog transmission interface, D-type port, with 15 holes on it, respectively transmitting different signals, and the VGA interface is also called D-Sub interface.
Features:
Theoretically capable of supporting 2048x1536 resolution picture transmission;
Since VGA is an analog signal transmission, it is susceptible to interference, and signal conversion easily leads to loss of signal;
At 1080P resolution, the user can clearly feel the loss of the picture through the naked eye;
It is recommended to use 1080P resolution for the following monitors.
VGA is the most widely used display interface. Most of the low-end displays have VGA interface, but because of its obvious disadvantages, high resolution can't reach the refresh rate and only image input has no sound input. It makes it difficult to play in the middle and high-end displays.
DVI interface
DVI (Digital Visual Interface [1]), which is a digital video interface. It was launched in 1999 by Silicon Image, Intel (Intel), Compaq (Compaq), IBM, HP (HP), NEC, Fujitsu (Fujitsu) and other companies to form the DDWG (Digital Display Working Group). Interface standard. DVI interface is more complicated, mainly divided into three types, DVI-A, DVI-D and DVI-I. DVI-D and DVI-I are divided into single channel and dual channel.
DVI-A, analog interface for switching VGA, has been deprecated.
DVI-A, digital interface, is divided into single channel (18+1) and dual channel (24+1). It is not transferable to VGA, and it is not possible to use adapters.
DVI-I, compatible with analog and digital interfaces, can be said to be the integration of A and D, can transfer VGA, but need adapter.
Features:
Only images can be transmitted, and the resolution is limited;
Only supports 8-bit RGB signal transmission, which is not perfect for some wider color gamut displays;
The interface is relatively large and inefficient, and cannot be applied to devices such as superbooks;
The compatibility of the device is relatively common, especially for flat-panel TVs.
DVI transmits digital signals, digital image information is directly transmitted to the display device without any conversion, thus reducing the digital → analog → digital cumbersome conversion process, greatly saving time, so it is faster It effectively eliminates the phenomenon of smear, and uses DVI for data transmission. The signal is not attenuated, the color is purer and more realistic, and it is also widely used at present.
HDMI interface
High Definition Multimedia Interface (HDMI) is a digital video/audio interface technology. It is a dedicated digital interface suitable for image transmission. It can transmit audio and video signals at the same time. The maximum data transmission speed is 2.25. GB/s.
Features:
The latest HDMI 1.4 standard, capable of supporting 4Kx2K resolution transmission with Ethernet channel, audio return channel, support for 3D functions, etc.
Support for 4K resolution output, which improves the support for today's 4KK TV and monitor support;
Support 3D function, can meet the display signal transmission requirements of 3D TV;
It can also support more than 30 gamut spaces, and can display the most vivid colors under various standards.
Display interface resolution
HDMI is a digital interface that provides the best video quality because all analog connections (such as component video or S-video) require no loss when converting from analog to digital. This difference is especially noticeable at higher resolutions, such as 1080p. Digital video will be sharper than component video, eliminating the softness and smearing found in component video. Tiny, high-contrast details such as text take this difference to the limit. In addition, the HDMI interface is widely used for many reasons, which also extends a variety of HDMI interfaces, mainly Micro, mini HDMI and standard HDMI interface.
DisplayPort (referred to as DP):
The DP interface is the successor to DVI. Nowadays, there are mainly DisplayPort interfaces and miniDP interfaces developed by Apple. The DP interface has improved a lot compared to DVI, and there have been qualitative changes in bandwidth and customizability.
In May 2006, the Video Electronics Standards Association (VESA) established the 1.0 version of the standard, and upgraded to version 1.1 after half a year, providing support for HDCP, which is also planned for launch this year.
The longest external connection distance of the DP interface can reach 15M, the rate can reach 10.8Gb/S, and it can support 2560x1600 resolution and 30/36bit color depth;
It also allows audio and video signals to be transmitted over a single cable, supporting a variety of high quality digital audio;
In addition to the four main transmission channels, it also provides a powerful auxiliary channel with a bandwidth of 1Mbps and a maximum delay of only 500us, enabling multiple functions.
The Apple miniDP interface is more powerful, not only the interface is small, but also supports the compatibility of various interfaces, just need to add a adapter.
At present, the DP interface is the latest 1.3 standard, the speed can reach 21.6Gb/s, the resolution can directly support up to 4K, mainly used in PC, which is why the current 4K display uses DP interface.
