Foreverserenity's reply to my quick review of the movie Next shows some of the confusion that revolves around the future of television within the United States, so I'd like to take the opportunity to offer up an article that covers the issue surrounding the transition to digital television broadcasts in the U.S.A.

First, lets address the question of When?  The answer to that is February 2009.  That's the important deadline that everyone should be aware of.  At that point the old analog TV signals that have been in use for the last several decades will be gone, replaced by fancy new digital TV signals in their place.

Now, what about the question of How? as in How does this affect me?  It affects everyone that receives TV signals in the U.S.A. in one way or another.  All of the older analog TV signals will go away and if you only have equipment that receives analog TV signals, you could turn your TV on and find there is no signal available to tune in at all.

That question should be followed up by a What? as in What do I need to do about this change?  If you receive your programming via satellite (mini-dish like Dish Network or DirecTV) it doesn't really affect you.  The satellite receiver you use converts the digital channels back into a signal that your TV equipment understands and is still able to display.  Consider the satellite receiver to be a D to A (Digital to Analog) converter.  As long as you remain a satellite TV customer and continue to use the equipment you've been using, you'd get some version of the TV channels you subscribe to.  You may find that the suite of available channels changes, and perhaps fewer non-HD (non-high definition) channels will exist, but one way or another you should still find several channels out there to watch if you want without having to rush out and buy yourself a new TV.

That What? question also might be asking about how this change affects cable TV customers.  The answer is much the same as how it affects satellite customers with a few important notes.  First, the old analog signals will go away, on cable as well as over-the-air.  So, if you use an older TV that was "cable ready" and didn't use a cable company provided set-top-box (stb), or use a third party stb (such as a TiVo box, or your own cable tuner box of a similar type...), then you will find you need to obtain a new stb that will receive the new digital channels and convert them back to analog so that your older TV can recognize the signals.

And finally, in the What? category, what about customers that don't get cable or satellite (or cable like services via FiOS or similar)?  Ah, great question.  Customers that are not subscribers of satellite TV or cable TV are definitely impacted.  Those customers will either need a new TV that receives digital signals (if they haven't already bought one), or they'll have to obtain a converter box (another stb type box) that will receive the digital signal and convert it back to analog.  This would be a one-time purchase, versus paying a monthly subscription fee for cable or satellite, but it would be a small cost item.  Reportedly the FCC has been working with the television broadcasters to try to get some sort of subsidized provision of these converter boxes done so that customers that need one (those that consider television a necessity, and in some areas I suppose that is the case given needs to get information about weather emergencies and the like) can get one cheaply or have it provided to them for free.

If you have questions still, and you might here, about What are all of these new high-defintion channels and won't I need new equipmet to receive them? you've been keeping pace nicely.  High Definition (HDTV) signals are somewhat special versions of the digital signals.  They are broadcast in a manner that provides for more detail in the video image when compared to the resolutions used in the past.

In the past, TV broadcasts were sent using 480 vertical lines of interlaced resolution.  This would be noted as 480i.  Interlaced meant that the signals were sent in a manner that updates half of the display in one pass, and then comes back and updates the other half of the lines.  Every other line is sent per pass, and then the alternate lines are sent in the next pass.  Sort of like filling in the spots on a checker board or chess board.  You don't get the whole board until after all of the spots on the board are filled in, except in the case of 480i (or other interlaced signals that could be used) it's actually a bit more like looking at piece of ruled noted book paper.  White line stacked on top of blue line, which is stacked on another white line then blue line pair, etc.

In the HDTV world, there are several other available resolutions, including 480 vertical lines of progressive resolution (noted as 480p), along with 720p (720 vertical lines of progressive resolution), 1080i (1080 vertical lines of interlaced resolution), and 1080p (1080 vertical lines of progressive resolution).  As the numbers get higher, the amount of information that is sent in the signal increases somewhat exponentially, and in addition, the horizontal resolution also increases so that more information is used to fill both the height (or depth) and width of the screen.

1080p is seen as the best of the bunch mostly because the entire screen is drawn in one pass.  With that said, virtually no broadcasters in the U.S.A. have any plans to move to 1080p broadcasts.  The equipment is too expensive, and the return on the investment just isn't enough at this point.  In addition, the difference between the image produced by sending a 1080i signal versus sending a 1080p signal isn't enough for most humans to detect.  Even for those lucky few folks that have invested in TV equipment that understands 1080p signals, their TVs will upconvert the 1080i signals to 1080p and do that work internally.

The more common resolutions that are broadcast for HDTV signals in the U.S.A. are 720p or 1080i.  FOX was a big proponent of using 720p signals.  Less bandwidth, signals that were a definite improvement over 480i, but not as expensive to generate and broadcast as would be 1080i or 1080p.  Most other networks headed into the 1080i direction.  Honestly, I've not paid enough attention to what FOX's current plans are, so they may have moved toward 1080i, but honestly, most veiwers probably couldn't tell the difference between 720p and 1080i when push comes to shove.

Now that we get past the resolutions that are broadcast, what about the various TVs that are out there?  You might have seen some of those resolution numbers written on TV specifications stuck on the TVs or boxes for TV in the stores.  The same numbers you see directly above.  So, as an example, you may see that you find a fairly inexpensive 32" widescreen HDTV that says that it uses 720p as it's 'native' resolution.  The native resolution is the standard resolution that the TV understands.  That's the resolution that the TV would use if the signal that it receives isn't being used to lower the resolution.  A TV that advertises 1080i as it's native resolution is capable of showing a 720p signal without changing that format at all, or the TV could change that 720p signal into an upconverted 1080i signal on it's own.  Anytime a 480i or 480p signal would be sent to the TV, as long as the TV was capable of showing at least a 720p native signal the TV would convert the signal into that native resolution unless the user sets the TV to use the resolution sent by the broadcaster (and even then the TV can't show more resolution than it is capable of so it would down-rez the signal back into one it is capable of showing).

Down-rez? you may ask.  Yes, if the signal that is being sent has too much information for the TV to handle, the TV converts the signal back to one that it can show.  So, if the signal being received at the TV calls for 1080i, but the TV only understands 720p, the TV converts the signal back to 720p and goes on about showing you the best 720p picture it can.

What does all of this really mean when it comes to replacing TVs or buying new TV equipment over the coming year and few months?  Well, if you've not been TV shopping lately, you'd have a hard time finding a TV set that only receives analog signals any more.  I believe we've passed the magic deadline when analog only TVs were permitted to be sold.  Most places you could shop for TVs you should have seen notices that warned you that the TV you are about to buy may not be compatible with then pending digital revolution (for TVs that only received analog signals).

TVs that are being sold now should be able to receive digital signals without needing additional hardware.  Note that doesn't mean that they can descramble cable signals or satellite signals.  It means they are supposed to be able to receive UN-encrypted digital TV signals and show them for you.  Cable providers are required to pass through the unencrypted versions of the digital signals for the local broadcast channels in their area, so you could hook the cable up to your TV, scan for digital channels and perhaps find somewhere around a half-dozen to a dozen digital TV channels broadcasting in your area.  Some of those might be high def broadcasts, some might be just a standard 480i signal broadcasting on one of the 'subchannels' of the main digital channel the broadcaster is assigned.

One of the advantages offered in the digital world is that a broadcaster can carve up their signal a bit if they wish and send both a lower resolution channel, or a few lower resolution channels, along with a higher resolution channel broadcast.  For example, in my area I can see a high def signal on the main digital channel, along with a sub-channel that shows me weather and/or traffic information.  From the Baltimore, Maryland area I can receive one set of broadcasts where classic TV programming (think Nick at Nite or TV Land type) is shown on the subchannel while the main network programming is shown on a high def broadcast on the main digital channel.

There are some types of encoding that are used to send the signals out on the cable or over the air, and provided you have a tuner that can receive the signals that are broadcast unencrypted you are able to watch those channels without paying any additional fees to the cable company, or without needing to subscribe to cable or satellite at all.  You just receive the HD broadcasts (and other digital broadcasts) and are able to watch them at your leisure.

I personally use an HDTV tuner card for a PC that I've built as a HTPC (Home Theatre PC).  It works great to receive and record (as a digital video recorder) HDTV broadcasts that I get 'over the air'.  I have tried using tuner equipment that would let my computer receive unencrypted digital signals sent on cable (or, in my case, FiOS) and though that equipment worked ok, there is still a lot of not so simple work that has to be done by the user to map the channels that are sent over the wire back into channels that my computer could find and record or display.  No where near as simple as just hooking up an stb from the cable provider and finding the channels on the numbers that the provider tells you they are using (for example they may say that you would receive MTV on channel 624, but you would have to map that signal to channel 62.4 or 64-4 depending on how you've configured your equipment).

As you might have surmised by now, there's still a lot of confusion in the marketplace about all of these various new standards, new signals, new equipment you may or may not need, and more.  As Foreverserenity said in the reply to the review of the movie Next, it's not a bad idea to wait for things to settle down in the marketplace.  Over the next several months we are likely to see more and more lower cost TVs hit the market.  Costs for smaller HD compatible sets have been coming down quite a bit.  If you aren't insistent on paying for more resolution than you need, you can get an HDTV set that receives 720p at about the 30" - 32" widescreen size for something in the $500 range.  Not the best price, or the greatest TV, but not bad compared to prices of just a few years ago, or compared to TV sizes from years past.  (As an example, it's not been that long ago that I paid about $400 for a 20" TV that has a VCR built into it, or pretty much the same price for a 27" TV set with picture-in-picture features.)

I expect, over the coming months, we'll see more and more of the bigger screen (37" and up) sizes hit the lower price points and in turn see the smaller sized sets come down into price ranges most people would consider affordable.  In the meantime, I too am saving my pennies up so that I can buy some new TVs in the future, with an eye towards a 42" (give or take) set for my living room area.  Bigger than that would be hard to fit in the space anyway, but smaller would be almost too small to think of watching in the same space.