It’s All Digital, Baby
The first thing to keep in mind when comparing DVI and HDMI is that they are both digital. This is good because you preserve the digital signal from your source device to your TV, instead of incurring conversion errors at both ends, and digital signal is less susceptible to interference than analog. It also helps because we can compare apples to apples.
The top computer video interface, largely because of its backward compatibility. A DVI-A or -I cable can carry a converted analog signal from a graphics card to an older monitor, which made it a painless upgrade for most users. Of course the bandwidth for higher resolutions and digital clarity were also appreciated.
Bandwidth here refers to how many zeros and ones a connection can move in one second. That is how digital signals are sent, so we can just count the bits and bytes. We explain DVI bandwidth in detail here, as well as the several kinds of DVI cable. But, for this article’s purposes, just keep in mind that the latest DVI cable, a DVI Dual Link cable, carries almost as much bandwidth as HDMI can, and more than enough for normal 1080p HDTV or 1920×1200 computer monitors (at 60Hz refresh rate)
If DVI can carry plenty of bandwidth, why a new set of cables? Well, where HDMI outshines DVI is more on the usability and features side. Most noticeably HDMI cables and ports are much smaller, which makes them easier to use, easier to build into a device, and they weigh less for use in portable devices. They also can carry CEC (Consumer Electronics Control signals, which can cut down on remotes or how much programming of them you have to do.
Remember that we are referring to HDMI 1.3 Category 2. If that sounds confusing, don’t worry it isn’t too bad. Like DVI, there are different types of HDMI, explained here. Previous versions or Category 1 cables can limit bandwidth, which is also explained in that link. The later versions are also able to support optional features (like True Color) manufacturers may include.
HDMI and Audio
One big plus of HDMI is that it can carry audio. That means you can hook up a source device like a Blue-Ray or DVD with one cable, instead of separate cables for audio and a DVI for video.
If the Digital Audio Converter in your source device is better than the DAC in your receiver, you will still want the former to do the conversion, and need the accompanying whack of cables. But if you have a nice receiver, or are using a source like a PC without a sound card, it saves money, hassles, and tangles. We explain how to use HDMI for PC Audio here.
So HDMI is Better than DVI?
In a word, yes. Just remember that it really isn’t better quality, but features, that make it better. If you won’t be using those features, there isn’t really a difference. In terms of compatibility and future proofing, HDMI is replacing DVI in the home theatre. DVI is still dominant in PCs, but monitors with both types of input as well as graphics cards or laptops with both outputs are increasingly common.
This is reflected in the extra features of HDMI being largely on the home theatre side. If you are shopping on that side, or for components for a home theatre PC, then those features are probably more attractive, and you should consider restricting your selections to those with HDMI.
If you are buying a computer and don’t plan any home theatre integration, equipment with HDMI and DVI is a great choice from a just in case perspective, but don’t shell out extra cash for it.
Whichever you are buying, the ace in your sleeve is that HDMI and DVI play nicely together. A simple adapter will take care of the video signal, though you will loose HDMI’s audio and other fancy features.
What about DisplayPort?
Found largely on the computing side, particularly on Macs and Dell’s monitors, this new entrant is still a rarity. DisplayPort has some interesting differences in how it works, potentially offering major advantages in the size and power use of what they call Direct Drive monitors. The hitch is: only one company has announced that they are working on Direct Drive display hardware.
I wouldn’t write it off entirely, but don’t spend an extra dime on it, and avoid equipment that uses it alone. There is no reason to spend money on DisplayPort at this point.