HD Specs
HDTV is actually part of the DTV (Digital Television) specifications,
which has many different video resolutions. The two main
resolutions to be concerned about are 720p and 1080i. The "p"
means progressive and "i" mean interlaced. In both resolutions,
every second has 60 frames of video. Progressive resolution puts
60 full frames on the screen every second. Interlaced resolution
puts 30 frames of only odd lines and then 30 frames of only even
lines up every second. Some people complain about the flicker
produced by interlaced video.
The 720p video resolution is 1280 X 720 pixels, which gives
921,600 total pixels and the 1080i video resolution is 1920 X 1080,
which gives a whopping 2,073,000 pixels.
Which resolution is better? Beauty is in the eye of the beholder,
and future battles may be fought over this question. Some people
like the slightly more "stable" picture of 720p, while others prefer
the greater resolution of 1080i. The best way to figure this out is to
run down to your local TV store and see for yourself.
SOUND
Just as your CDs sound better than your old audiocassette tapes,
HDTV's digital audio signal sounds better than standard television's
analog sound. Also, some HDTV programs include Dolby Digital 5.1
surround sound. Of course this means you need 5.1 speakers to
take advantage of the better sound.
TV
You will have to buy a new HDTV. Some HDTVs come with built-in
tuners, while others do not. The tuner converts the signal into
something that your TV can recognize. HDTVs that do not come
with a tuner are commonly called "HDTV Ready." An HDTV without
a tuner is worthless.
There was a big legal fight between Consumer Electronics
Association (CEA) and the FCC about including tuners in all HDTVs.
The FCC wanted tuners to be included, while the CEA did not. FCC
reasoned that the including tuners would increase adoption of
HDTV. The CEA said that tuners are only for people who want to
receive signals via antenna and is worthless for people who want to
use digital cable or satellite, which have built-in tuners.
Another reason that the CEA argued against including tuners into
HDTVs is that it would drive up the costs of manufacturing the
HDTV. It looks like the FCC won, and as of July 2004 HDTVs with
screens of 36 inches or more must be sold with a tuner included.
Smaller sizes will be phased in over the next three years.
HDTV content uses MPEG-2 compression. A properly compressed
HDTV signal delivering 1080i content is about 19.2 megabits per
second, but the actual rate can vary. Some content providers
compress the signal to a greater degree, so you may see attempts
to deliver HDTV streams as low as 5-6 megabits. Image quality
would definitely be worse than at full bitrate.
For shows that are broadcasted in native HDTV, the video, in 16:9
aspect ratio, will fill up the whole frame of your TV or computer
tuner window. The following screenshot was taken from Navy CIS,
also from CBS. It is a native 1080i or 1920 x 1080 pixels format.
For shows and sporting events that are in native HDTV format,
pictures do not do them justice. You must see it live to appreciate
the quality.
Unfortunately, there's no easy way for a consumer to determine
the actual bitrate, other than by seeing decreased image quality. In
fact, many HDTVs don't even tell you the active display mode
(1080i, 720p). When you're shopping for HDTV products, make
sure they support either 720p or 1080i natively.
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