What Is Dual DVI?

The DVI interface is a technology for high-speed transmission of digital signals invented by the Digital Display Working Group (DDWG) established on the Intel Developer Forum in September 1998. There are DVI-A, DVI-D And DVI-I three different types of interface forms. DVI-D has only digital interfaces, and DVI-I has digital and analog interfaces. At present, DVI-D (24 + 1) is the main application.

DVI interface

The DVI interface is a technology for high-speed transmission of digital signals invented by the Digital Display Working Group (DDWG) established on the Intel Developer Forum in September 1998. There are DVI-A, DVI-D And DVI-I three different types of interface forms. DVI-D has only digital interfaces, and DVI-I has digital and analog interfaces. At present, DVI-D (24 + 1) is the main application.

Chinese name

Digital video interface

Foreign name

Digital Visual Interface

Short name

DVI (Digital Visual Interface), that is, digital video interface. It was established on the Intel Developer Forum in September 1998. It is made up of Silicon Image, Intel (

DVI-A (12 + 5)

12 + 5 pin DVI cable is currently the most common DVI cable on the market. It is less than or equal to 1920

In order to meet the requirements of high-definition display, scanning generally uses 1080i @ 60Hz format (that is, interlaced scanning, line frequency 33.75kHz, field frequency 60Hz, pixel frequency 74.25MHz). In practice, to reduce the line frequency conversion, all video input formats For example, 480P, 576P, 720P, etc.) are uniformly converted to 1080i @ 60Hz format output through format conversion (Scale and De-interlace, etc.), that is, multi-frequency normalization. The DVI interface discussed in this article considers applications based on the above-mentioned digital television standards.

The DVI interface has 3 types and 5 specifications, and the terminal interface size is 39.5mm × 15.13mm.

Interface type	advantage	Disadvantage	Suggest
VGA	Supports resolutions up to 2048x1536 and supports hot swap	Easy to be interfered by other signals, the font is a bit garbled at high resolution	To avoid susceptible images, use VGA at 1920x1080 resolution and within 20 inches.
DVI	The picture is more delicate at high resolution and is not easy to be interfered by the signal	There are many types, and most DVI cables do not support resolutions above 1920x1200. Hot plugging may burn out the circuit	It is recommended to use DVI for full HD displays. If the resolution exceeds 1920x1200 or 3D, dual-channel cables are required.

Misunderstanding

1. Misunderstanding: The image quality of the two interfaces of DVI and HDMI is very different.

Under the current circumstances, the image quality of the two interfaces of DVI and HDMI is not significantly different at the same resolution, but with the development of the HDMI interface, it can provide more functions than the DVI interface.

2. Misunderstanding: HDMI interface can transmit audio signals, DVI cannot transmit audio signals

Both the DVI and HDMI interfaces transmit TMDS signals. In fact, TMDS only needs 4 pairs of wires, and the other pins are auxiliary. The difference is that the DVI signal does not contain audio when it is encoded, and the HDMI signal is packaged with audio. When manufacturers encode audio signals and video signals into TDMS format, the DVI interface can also transmit audio signals.

Advantages of HDMI

HDMI 1.3 version:

1. Added support for new lossless compressed digital audio formats Dolby TrueHD and DTS-HD Master Audio .

2. Higher refresh rate: Under the same 1920x1080 resolution mode, HDMI 1.3 provides a 165Hz refresh rate higher than the 120Hz refresh rate of the dual-channel DVI interface.

HDMI 1.4 version:

1. Ethernet channel: HDMI specification 1.4 adds a data path to the cable to achieve two-way high-speed transmission. After the devices with this function are connected, they can send and receive data at the speed of 100Mb / s on the Ethernet line, and make these devices IP-based devices immediately. The HDMI Ethernet channel allows Internet-enabled HDMI devices to share their Internet connection with other HDMI devices without using other Ethernet cables. This new feature also provides the interconnect architecture required to share content between HDMI devices.

2. Higher resolution: support 3840 × 2160 24Hz / 25Hz / 30Hz; 4096 × 2160 24Hz resolution. The new specification supports 4096 × 2160 resolution, allowing the HDMI interface to transmit content with the same standard resolution used by many digital cinemas. The dual-channel DVI interface can only support 2560x1600 resolution.

How to choose DVI interface and what are the advantages of DVI interface

The advantages of the DVI interface are mainly reflected in the following two aspects:

1.Fast speed: DVI transmits digital signals, and digital image information is directly transmitted to the display device without any conversion. Therefore, the digital analog digital tedious conversion process is reduced, which saves time greatly, so It is faster, effectively eliminates smearing, and uses DVI for data transmission. The signal is not attenuated, and the colors are more pure and realistic.

2. The picture is clear: The computer transmits binary digital signals. If you use a VGA interface to connect to a liquid crystal display, you need to first convert the signals into R, G, and B primary color signals through the D / A (digital / analog) converter in the graphics card. And line and field synchronization signals, these signals are transmitted to the inside of the liquid crystal through the analog signal line, and the corresponding A / D (analog / digital) converter is required to convert the analog signal into a digital signal again to display the image on the liquid crystal. During the above-mentioned D / A, A / D conversion and signal transmission, signal loss and interference will inevitably occur, resulting in image distortion and even display errors. The DVI interface does not need to perform these conversions, avoiding signal loss and making The sharpness and detail of the image have been greatly improved.

In the edge fusion system, it is basically used to collect dual VGA signals or dual DVI signals. Next, we will elaborate on the relevant issues that should be paid attention to when selecting a DVI dual channel capture card:

Is DVI a real digital signal architecture? The acquisition card of DVI digital signal architecture is much more difficult to develop than the VGA acquisition card, so we must pay attention to whether the selected card has a simple VGA. Turn to DVI interface module instead of real DVI-based pure digital capture card.

Due to the limitation of development technology, the technical threshold for DVI capture card including VGA capture card to capture independent graphics card output and non-independent graphics card output will be very high. When choosing this kind of products, we must pay attention to distinguish whether to support it.

Whether it has on-board cache is very important. Many key performances of the capture card need on-board cache to improve.

DVI dual-channel acquisition card , not a simple two-card copy, it is really necessary to combine two DVI acquisition cards into one, two cards in one slot, and simultaneously acquire two DVI signals, and the parameters must be independently adjustable and cannot affect each other. It is not that two cards can be used only when they are completely set to the same, and one cannot be set to affect the other. Pay attention to distinguish when choosing.

The application of the software should be relatively simple, because the DVI dual-channel acquisition card belongs to the acquisition of non-standard image signals, and many parameters need to be debugged, so the software design should be convenient for beginners to successfully debug and achieve the best results quickly