Background: As the HDTV market continues to heat up,
consumers are in need of being educated on the latest technology
in order to make intelligent purchasing decisions. There are a
plethora of articles explaining the technical pros and cons of
the 3 dominant HDTV display technologies namely: LCD, Plasma,
and DLP. However, one all- important, but overlooked feature in
selecting a HDTV set is the type of HD video connection. The
video connections available for HDTV are: component video, DVI
(digital video interface) and HDMI (high definition multi-media
interface). We will discuss briefly the pros and cons of each.
Component video cable commonly referred to as R, G, B
(Red, Green, Blue) actually consists of 3 separate cables
because it distributes the 3 primary color components to the
display. All colors can be generated from weighted distribution
of each Red, Green and Blue color components. Of the 3 HD
connection technologies available today, analog component video
is the most mature technology.
-Advantage: Analog component video cable is mature and
-Disadvantage: component video cables are analog! All
HDTV sets are inherently digital therefore extra digital to
analog and analog to digital conversion is necessary in order to
process the video. This extra conversion can introduce video
artifacts. Since all HDTV’s are digital, it only makes sense to
use an all- digital connection such as DVI or HDMI.
DVI(digital video interface) as the name suggests is an
all-digital video connection. Unlike analog component cables the
DVI interface transports the original digitized R,G, B video
signals from the HD source to the HD display. Since it all
digital, no artifacts or degradation will be incurred. You will
get EXACTLY the picture that the video source supplies with no
degradation. DVI connection is often found on HDTV as well as PC
-Advantage: DVI is ALL-digital, so there is no picture
degradation from source to display.
-Disadvantage: Digitizing R, G, B requires extremely high
bandwidth. The aggregate data rate of the digital R, G, B
signals is 1.65 Gbps! The high bandwidth means that cable
quality is important and also the link distance is limited.
Typical link budget for a DVI is ~ 15 ft.
HDMI (high definition multi-media interface) is the
latest state of art audio and video connection. Technically,
HDMI is identical to DVI with 3 notable differences. 1) HDMI is
a much smaller connector (it looks like an U.S.B. connector), 2)
HDMI utilizes copy protection called HDCP (high definition copy
protection) and 3) HDMI carries multi channel digital audio.
HDMI, like DVI, is ALL-digital therefore picture quality is
“perfect” from source to display.
-Advantage: HDMI is a single digital video and Audio
connection. Only 1 single cable is needed to transport both
audio and video! This significantly reduces cable clutter behind
your theater setup. HDMI is all-digital therefore there is no
picture degradation from source to display.
-Disadvantage: Like DVI, the link distance is limited and
a high quality cable is required because of the inherently high
bandwidth required to transport digital R, G, B. video.
You may view pictures of DVI and HDMI connections at : http://www.octavainc.com/faq.htm
Conclusion: As the HDTV market continues to mature,
consumers will need to be educated on the HDTV video connections
available. We have outlined briefly the main features along with
the pros and cons of each connection solution, so the consumer
can make intelligent choices in selecting the HDTV video