You've decided to buy an HDTV. Congratulations! Now it's time for you to make a whole bunch of
First, how are you going to get your HDTV signal? Will you be using the over-the-air (OTA) signal? Will
you be using a satellite service? Or is cable your delivery method of choice?
The answers to the above questions have a profound effect on the type of features you're looking for.
Let's start with the basic scenario: you're a basic end user. You want to be able to stick an antenna on top of
your TV and ... well ... watch HDTV. You don't want an external set-top box (STB), and you don't want cable or
satellite. Let's also assume that you've done your due-diligence and you're sure that you have adequate signal
for all the channels (hints on OTA reception can be found
You would think that the basic situation would be the easiest to conquer. Unfortunately that's not the
case. Many, if not the majority, of the high-definition TVs wouldn't work for you. Unlike standard
televisions, not all high-definition TVs have high-definition tuners. Some are merely considered HD-ready.
This means that the television is capable of displaying the picture, but you must feed it an already decoded
signal. Historically there are two main reasons for the lack of HD tuning. First, manufacturers feel that
consumers will eventually get their signal from cable and, for the most part, the tuner would be useless in that
scenario. They, in turn, cut the tuner to save some money. Second, many displays (e.g. plasmas) are
technically monitors and, as such, aren't subject to some of the same regulations as televisions.
In any case, if that were truly your only usage scenario, all you would need is an HDTV display that comes with a
tuner. However, most people are going to need more. Most people are going to want ESPNHD, DiscoveryHD, etc.
In short, most people are going to want either cable or satellite. In steps STBs (set-top-boxes), cables,
connectors, and slots, which is what we're really talking about this week.
For the meantime we're going to disregard Digital Cable Ready (DCR) TVs and assume that you'll be using an STB
tuner. It's not that DCR HDTV isn't a great concept. You'd be hard-pressed to find a stronger advocate for Open
Cable than I. However, its true strength is that it opens up the market for TiVo, MCE, etc. (we'll be talking
about DCR in a future column).
There are four standard methods for connecting a cable box to an HDTV: Component Video, DVI, HDMI, and Firewire.
You're probably already familiar with component video; it's the granddaddy of HDTV connectors. With component,
three wires (Y, Pb, Pr) carry an analog signal to your TV. This signal is raw (i.e. decoded) and very
large. There is rarely any encryption on this signal, but that doesn't matter because the equipment needed to
digitize the stream is too expensive for consumer-grade equipment.
DVI (Digital Visual Interface) and HDMI (High-Definition Multimedia Interface) are two very similar
technologies. Like component, both DVI and HDMI carry a raw signal to the television. However, unlike
component, they carry their signal digitally. (As a general rule, it's better to keep a signal digital for as
long as possible because of crosstalk, attentuation, and interference.)
There are two differences between DVI and HDMI. First, HDMI uses a more compact connector. Second, and
more importantly, HDMI carries both the video and the audio signal. At first this might sound like a great
idea. However, in practice, it's only a marginal improvement. Most consumers want a surround-sound
environment. Since the TV can't handle that, it's not an advantage to have audio on the same cable. Both also
give you the advantage of hooking your TV up to your computer (pending, of course, that it has DVI-out, and you happen
to have a DVI-to-HDMI adapter, if necessary).
Much more important than whether your TV offers the DVI connector or the HDMI connector is whether or not that
connection is HDCP (High-bandwidth Digital Content Protection) compatible. If you recall in last week's column we
talked about "authorized technologies" for the broadcast
flag. Well, it's about to pop up here again. For the same reason that consumers love a digital signal
(i.e. no degradation), content providers fear it. HDCP is considered an authorized protection technology.
This means that the digital signal is encrypted between the source and the television. It's also likely that, in
the future, certain devices will refuse to send the signal to your television without HDCP.
The last connection type, Firewire, is a little bit different. All the protocols send their signal in raw form,
but this is not the case with Firewire. Instead, Firewire sends the actual MPEG2 stream. As such, the
Firewire data stream is much smaller (19.2 Mbps for most HD content). This connection relies on the display
device to decode the information. While not as common as the other types, Firewire is essential if you're looking
to archive your data to DVHS.
There are clearly many other things to consider when looking at HDTV. However, my time is up, and I'm sure that
this discussion will continue in the comments section. Next week: display technologies.
Until then, save my seat!