 HDMI, or High Definition Multimedia Interface technology
developed by the HDMI Working Group in 2002, is the newest digital
media interface based on the DVI-HDCP
model. While
DVI handles only uncompressed,
real-time digital video, HDMI can handle both digital video as well
as multi-channel audio. The most attractive feature of HDMI is that
it has the ability to turn upwards of 10 separate cables, audio and
video, into one easy to install, small connector cable. There are,
however, two HDMI connector types which are “Type A” which is used
for
consumer electronics such as televisions and DVD players, and
“Type B” which was designed as a dual link for PC applications
requiring frequencies above 165 MHz.
HDMI has several features that make it more attractive to the
consumer electronics industry. Among them are its
Consumer Electronics Control (CEC)
support based on the AV.link protocol allowing it to be controlled
using a universal remote, and its bi-directional communication
between HDMI devices allowing for intelligent rendering of specified
formats. Also, HDMI, like DVI, transmits uncompressed high
definition video data therefore the picture maintains its high
quality without losing color depth, or altering brightness or
contrast. Also,
unlike
DVI's 5 meter limit, HDMI cable can be run up to 15 meters when used
properly.
As far as display compatibility is concerned, HDMI supports every
uncompressed standard, enhanced, and high definition video format
including the older PAL
format. Furthermore, HDMI’s high definition television
resolutions supported are 480i, 480p, 720p, 1080i, and 1080p.
Most standard PC monitor formats are also supported by HDMI.
These include VGA,
XGA, and
SXGA at resolutions of
1600x1200 and beyond.
HDMI also supports uncompressed audio formats and compressed
audio formats including Dolby Digital, Dolby Digital EX,
DTS, and DTS EX.
Following the DVD-Audio standard, HDMI was built to handle 1-8
uncompressed audio streams and has sample rates of 48, 96, or even
192 kHz. Compressed multi-channel audio streams can also be
handled at sample rates of 192 kHz.
Fortunately
for those with numerous DVI devices, HDMI is backwards compatible
with these and devices using the
EIA-861
DTV profile. The
additional features of HDMI, however, including digital audio and
Consumer Electronics Control (CEC),
will not work on these systems. |
