DVI/ HDMI vs VGA in Digital Signage
November 6, 2014
As DVI and HDMI connections become more and more widely used in digital signage, we are often asked: which is better, DVI (or HDMI) or VGA? There is no clear answer to this question.
First, let’s get some basic knowledge of the elemets DVI and HDMI are exactly the same as one another regarding image wuality and resolution. The main differences between HDMI and DVI are that HDMI carries audio and video signal; further more HDMI uses different types of connectors. Technology wise both HDMI and DVI uses the same encoding technology, and for that reason DVI source can be connected to an HDMI connector on diplay, pr vice versa, with a DVI/ HDMI cable with no use of signal converter.
What are the difference between DVI, HDMI and VGA?
DVI / HDMI and VGA video are all video signals which support a variety of resolutions, each one of them deliver the signal from source to display in different ways. The main difference is that DVI / HDMI delivers the signal in a digital format. VGA is an analog format, which deliver the signal, not as adigital stream, but as a set of varying voltages representing the red, green and blue components of the signal.
DVI / HDMI and VGA deliver signals as red, green and blue color componets, together with sync information. The DVI / HDMI standard delivers these along three data channnels in a format called T.M.D.S., which stands for “Transmission Minimized Differential Signaling”. This basically involves a blue, red and green sync that are added ad separate the channels.
VGA is delivered, almost similarly, with the color information split up three ways. However, VGA uses a color difference type signal, which consists of Luminance, the green red or blue channel representing the total brightness of the image. The sync pulses for both horizontal and vertical are delivered on the Y channel.