DVI vs CHA
A digital visual interface (DVI) is a port used to connect display devices, such as LCD monitors or projectors, with the output device. DVI only supports connections between digital-to-digital devices.
Industry group Digital Display Working Group (DDWG) developed DVI, which began as a way to get rid of legacy video display systems based on analog technology. Uncompressed data is sent out over DVI for display on specific display devices.
Short for Video Graphics Adapter or Video Graphics Array, VGA is a popular display standard developed by IBM and introduced in 1987. VGA provides 640 x 480 resolution color display screens with a refresh rate of 60 Hz and 16 colors displayed at a time. If the resolution is lowered to 320 x 200, 256 colors are shown. VGA utilizes analog signals, which means it's only capable of lower resolutions and a lower quality display on screens.
Both DVI and VGA are methods used to connect monitor with computer. They support different cable lengths. They are used to transport video between PC and monitor/TV/Projector. They do not support audio. Hence a separate audio cable is needed.
DVI offers a higher quality signal compared to VGA. The difference is particularly noticeable at higher resolutions. The video quality is a factor of the mechanism of operation and the length and quality of the cable.
Mechanism of operation - From a user's point of view, both connectors work in the same way: devices have female ports and the connector cables have male endpoints. The signal is transmitted from the source device via the port to the connector cable and the destination, which is a display device.
VGA connectors transmit analog signals. The digital video signal received from the source is converted to analog to be transmitted via the cable. If the display device is an old CRT (Cathode Ray Tube) monitor, it accepts an analog signal. However, most display devices are now digital; so they convert the VGA connector's analog signal back to digital. This conversion from digital to analog and back results in a degradation of video quality for VGA connectors.
Video signals transmitted over DVI need no such conversion because they are digital-only. Consequently, picture quality is better. The difference may not be noticeable for text or even SD (standard definition) video but can be seen for HD videos and hi-resolution images or on hi-res displays.