Set-Top Boxes Buying Guide

Buyers' Guide to Set-Top Boxes Contents

• What is Digital TV and what will it do for you?
• HDTV and SDTV
• Resolutions
• Multichannelling
• Future services 
• What is a Set-top Box (STB)?
• Inside the box
• Why does my STB put black bars on my TV?
• What about Electronic Program Guides (EPGs)?
• Personal Video Recorders (PVRs)
• Timeshifting
• Foxtel STB goes PVR
• Using your other existing equipment
• The bottom line

------------------------------------------------------------------------------------What is Digital TV and why is everyone making such a fuss about it? What is High-Definition (HD) TV and how is it different? Do you have to get rid of your old TV and buy a new one? For that matter, what about your existing VCR, DVD and sound system? Should you act now or wait a while? Do you need a Set-top Box (STB) and what sort should you get - a High-definition STB or a Standard-Definition STB? And why is it called a Set-top Box when it usually sits under it?

The move to Digital TV is a minefield of questions like these. The short answer is yes, you DO need a Digital TV receiver, called a Set-top Box (STB). And despite the name, you can choose to put it on top of, underneath or beside your existing analog TV. But to understand the what, how, why and when of getting the right STB to suit your needs, you need to know a little bit about Digital TV.

What is Digital TV and what will it do for you?

Firstly, why the switch to Digital TV? Quite simply, to overcome the problems you get with traditional analog TV. Digital TV offers widescreen viewing, DVD quality, surround sound, extra stations and a crisp, clear picture free from ghosting (double images), fuzziness and "snow".

Sounds good, but what if you're quite happy with the TV and reception you get now? Well, regardless of what you think of your existing TV, you will experience the benefits of Digital TV sooner or later, because the analog network is due to be "switched off" by 2008. When that happens, your old analog TV simply won't work without an STB plugged into it

So, don't panic. You don't have to get rid of your current TV or other equipment. What you will need to do though, at a minimum, is add a Digital TV receiver (or STB) and you can do that now at a minimum cost of only about $100. Or, if you want to go all-out, you can take your investment to 10 times that amount just for the STB -- thousands more if you add a high-definition screen, surround sound and other extras.

There, that's the hard part over.

Now, let's look at the fun part and see all the extra benefits you can get by moving to Digital TV (via an STB) sooner rather than later.

The move to Digital TV has been compared in importance to the move from black-and-white TV to colour TV. In a nutshell, Digital TV offers a whole world of quality and entertainment options that were never available under the old analog TV system. They include: clear, crisp, ghost-free pictures; CD quality surround sound; widescreen format (when transmitted); extended program information (when transmitted); DVD quality viewing; multiple viewing angles (especially for live sport), closed captions (when transmitted) and teletext service, additional information channels for special events (such as the Olympics, football, cricket, car racing etc).

There's a whole lot of extra equipment you can add to maximise your viewing pleasure, such as a wide screen, surround sound system, DVD burner or hard-disk drive based recording system. But even if you just get add a stand-alone STB to your current setup, you're going to love Digital TV.

Digital TV is available now -- 24 hours a day, seven days a week. TV stations are currently transmitting the same programs using digital and analog signals. The simplest way to experience the benefits of Digital TV is to attach an STB to your existing television. For most people, this will be a Standard-Definition (SD) STB rather than a High-Definition (HD) STB, because without there's really no point getting a HD-STB unless you have a high-definition screen on which to view it.

It is important to note that all digital programs are broadcast in SDTV format, but only some are transmitted in HDTV format. So even if you have an HD-STB and an HD screen, you will only get the pleasure of HDTV on selected programs.

More about the various resolutions available later in this guide.

A lot of the benefits of Digital TV can be summed up in "higher quality" and "more information".

Higher quality is due to digital signals being able to resolve the problems caused by interference (electrical and geographical) and fluctuations in signal strength that plague analog TV.

More information is provided via Digital TV due to the greater compression that can be used with digital signals, so they can hold several times the amount information as analog signals.

Australia has adopted the European DVB-T standard to replace our existing analog PAL system. Once again, our system will differ from the US, which is using the American-developed ATSC standard to replace its analog NTSC system.

HDTV and SDTV

Let's get one thing straight: Digital TV is not just HDTV - it's just that HDTV is so gorgeous that it gets the lion's share of publicity. HDTV is high-resolution digital television (DTV) combined with Dolby AC-3 surround sound. To watch HDTV you need at least two things: a HD-STB and a HD-capable screen (whether it is plasma, rear projection, LCD or CRT). To get the most out of it you should also have a decent sound system (preferably capable of Dolby Digital 5.1).

The big advantage of HDTV, of course, is that it gives you widescreen format plus a higher resolution -- and therefore, sharper -- picture.

Resolutions

HDTV in Australia can supply images with up to 1080i (interlaced) lines of resolution - ie, 1080 lines of 1920 pixels with 50Hz interlaced scanning. At this level, HDTV quality is technically far better than what you get from a DVD.

When people refer to HDTV they usually also include 720p (progressive) and 720i (interlaced) formats. This is 720 lines of 1280 pixels. The progressive formats have twice the amount of vertical scan lines and are therefore of higher quality than their interlaced equivalents - eg, 720p is clearer than 720i. The benefits of HD pictures are particularly noticeable on larger widescreens and when using high-resolution projection equipment.

HDTV can also include 576p, as "High-Definition" technically includes anything above the 576i standard of SDTV. Some stations broadcast their HDTV content at this 576p standard, so, even if you have a high-resolution TV and a HD-STB you will notice quite a difference between this content and content which is broadcast at the top-quality standard of 1080i.

For this reason, from a buyer's point of view, you need to make sure of the numbers because a screen can be marketed as a "high-definition" and not be capable of the higher resolutions that you are really looking for.

SDTV broadcasts also provide widescreen picture format with DVD picture quality and CD-quality sound (MPEG digital stereo sound and/or Dolby Digital Sound), but at 576i resolution (576 lines x 720 pixels @ 50Hz interlaced). Most recent model analog sets are capable of displaying 576i when connected to an STB. It is worth noting that the 576i SDTV format is almost identical to the quality of DVD movie discs, so even an SD-STB will give you crisper, clearer quality than analog reception on your existing (older) TV.

HDTV is still not yet being broadcast all the time. The good news for those with a SD-STB is that the Federal Government requires broadcasters to provide an SD signal at all times. So anyone with an SD-STB will always be able to receive digital television even when the higher quality HD television signal is being transmitted. If you have an HD-STB you will still receive SD signals when HD signals are not available.

Multichannelling

Another benefit of Digital TV is multichannelling: the broadcasting of more than one channel of programs (in SD format) at one time. Because digital signals can be more highly compressed than analog signals, Digital TV can carry several TV stations in the space used by one analog station.

The Federal Government allows ABC and SBS to use multichannelling, but not commercial broadcasters. This gives the ABC and SBS the nod to broadcast extra programs such as educational, science, art, children's, foreign language, news and even drama.

ABC for instance, broadcasts ABC2, its digital-only, free-to-air TV channel offering new and timeshifted ABC programs. SBS broadcasts SBS World News.

In addition, SBS broadcasts two multilingual radio services and the ABC broadcasts audio streams of its Internet radio services, DiG, and DiGJazz.

Future services

The initial vision for Digital TV encompassed ideas like so-called Interactive TV, internet access, T-commerce (TV shopping) and new information services under the broad heading of datacasting, but these are still some time off.

What is a Set-top Box (STB)?

A digital set-top box is needed for receiving Digital TV broadcasts, because the vast majority of TV sets do not yet have such a tuner.

An STB is a device that receives and decodes digital television (DTV) broadcasts so they can be displayed on analog television sets or other display devices, such as computer monitors or projection screens. These can be SD or HD broadcasts, depending on the type of STB you use. In the most straightforward configuration, you simply plug the STB into your existing aerial and TV set, using either a composite, S-video or component video cable. It will usually scan and find any available channels. The STB then receives the digital stream being broadcast and decodes it so your existing analog TV can understand it. You can, of course, also connect it to your sound system and VCR.

Basic SD-STBs can cost as little as $100 or so, while HD-STBs usually cost a few hundred dollars more. The price of both types of STB can vary widely, depending on their feature set. As mentioned previously however, there is no point getting an HD-STB unless you have a high-resolution screen to use with it, and even if you do, the lack of HD content means that a lot of the time you will be viewing programs in standard-definition.

Don't let that put you off, though. If you want the ultimate in quality, more HD content is gradually being made available and quite simply, nothing else compares (there are also a number of SDTV and HDTV tuner cards available for PCs and even external USB-based Digital TV receivers for notebook computers).

Inside the box

A typical STB has one or more microprocessors for running the operating system (OS), possibly Linux or Windows CE, PowerTV, JavaOS or any one of a number of small "embedded applications". To the end user, it doesn't really matter what OS is used and usually it is not able to be accessed by the user. A set-top box also includes RAM, an MPEG decoder chip, and more chips for audio decoding and processing. Again, they include everything required and are usually not upgradeable.

Why does my STB put black bars on my TV?

If you've watched a widescreen-format DVD on your standard format analog TV you will have noticed the black strips across the top and bottom of the picture. You will get the same thing when using an STB to view widescreen content.

Standard analog TVs use a 4:3 (four by three) aspect ratio, which means it's a little wider than it is taller. For every four units of width our TV screen has three units of height. This is a hangover from the when the film industry standardised on the size of film, and in 1941 the same standards were adopted for television broadcasting. In a bid to attract customers, cinemas later adopted widescreen formats, such as Cinemascope and Vistavision, but until recently TV remained on the old standard.

The most common theatre screen aspect ratio is 16:9 (16 by nine), and Digital TV has once again adopted the same format. So, to show the wider picture on a "square" screen, the depth of the picture has to be reduced, leaving black bars top and bottom. This is called letterboxing.

A mixture of programs is being broadcast - some still in 4:3, others in 16:9 format. Both picture shapes need to coexist for quite a while. Some set-top boxes give you the option of viewing widescreen pictures in this "letterbox" format or "centre cut" full screen format (with the 4:3 section "cut out" of the 16:9 picture).

Some television content is originally produced in 4:3 aspect ratio and will display on a widescreen TV with vertical black bars on each sides of the screen. This is called pillarboxing. Sometimes, on a widescreen, the letterbox and pillarbox effects can even be combined to give you a "postage stamp" effect.

Sometimes, particularly in retailers showcasing many TVs, you will see incorrectly displayed images which have been stretched or squashed horizontally to fit a 16:9 picture on a 4:3 display (giving you extra-tall, skinny people), and 4:3 pictures stretched out to fit widescreen monitors (very short, extremely stocky people). This is, of course, NOT how you are expected to view digital content in your home.

What about Electronic Program Guides (EPGs)?

For those of us who find it difficult to program our video recorder (which is most of us) the advent of the Electronic Program Guide (EPG) is a blessing. An EPG is basically the onscreen equivalent of your printed TV guide, with the advantage that it is always up-to-date and accessible at the push of a button on the remote control. This really becomes useful when it can be used to schedule programs for automated recording on to the hard-disk drive of a Personal Video Recorder (PVR). At last, choosing programs to record becomes a simple point-and-click process.

Alas, while the EPG is good in theory, in practice it has not been possible until very recently, and even now EPGs are in their infancy. So far, the only EPGs available are the one included with Foxtel Digital (the Foxtel Digital Electronic Program Guide that comes with the extra-cost optional Foxtel iQ Personal Digital Recorder) and the recently introduced "Iceguide" - a subscription-based free-to-air digital television guide put together by Australian-owned IceTV (www.icetv.com.au). For a weekly fee, Iceguide provides an on-screen, week-in-advance guide of free-to-air television channels.

The drawback is that the Iceguide runs on a PC with an Internet connection and while it supports many PC-based PVR applications, it is currently limited to the Topfield TF5000PVRt, which connects to a PC via a USB connection.

Personal Video Recorders (PVRs)

PVRs are the next generation of television recording devices replacing the VCR. Unlike the VCR they use an internal hard disk for storing many hours of recorded programs - typically over 40 hours.

PVRs come in many brands and configurations and include some combination of STB (HD or SD), an internal hard drive and DVD burner.

A top-line PVR may have all three devices built-in - STB, hard drive and DVD burner. Or it may just have the STB and hard drive, or the STB and DVD burner. Depending on configuration, they range in price from around $500 to three or four times that much.

Timeshifting

Some STB PVRs have twin tuners, which allow you to record two broadcasts at once. Combined with a hard drive, you can actually be recording two shows live, whilst watching one that has been recorded to disk previously. The hard drive is a valuable addition that also gives you "wow-factor" features like timeshifting, which lets you pause and rewind a live show and then watch the start of a broadcast while continuing to record the rest of it.

Foxtel STB goes PVR

The FOXTEL iQ is a top-line STB and PVR combination that combines with the Foxtel EPG, but is available only to FOXTEL subscribers. Foxtel Digital subscribers can look up a program using the EPG and program them for recording to the hard drive. Its dual-tuner design allows two shows to be recorded at once, even while you are watching a different show that has been recorded previously. The player also supports timeshifting.

Using your other existing equipment

The variety of makes, models and features of STBs, including PVRs that incorporate STBs, is confusing enough, but what about your existing equipment?

Although you could put together a more elegant and integrated solution if you started from scratch, barring Lotto winners, most people will want to simply add to their existing entertainment system in the most economical fashion.

The good news is that you can move into Digital TV with a STB and keep your existing analog TV and your VCR, your DVD player and your sound system. Thanks to the variety of standard input/output formats you can connect all of these types of devices together. However, it is a good idea to map out your connections before heading off to purchase your shiny new STB or PVR. Draw up each of your existing components and how they are currently connected, noting all plugs/ports, and make sure the device you are going to add has the appropriate connections.

Obviously, if you are adding a PVR, you may elect to remove your old (and now redundant) VCR and/or DVD player from your new entertainment system. At the very least this will cut down on the number of remote controls you have to handle - or, you could elect to do that later with a Universal Remote Control that can combine the functions of several controller into one (see our Universal Remote Control Buyers Guide).

The bottom line

You can get an STB in three ways:

• As a standalone decoder unit that you plug into your existing analog TV and other entertainment system components (VCR, sound system etc).

   

• As a built-in part of a widescreen Digital TV set (at least that's one less remote control you have to deal with). However, this is usually a Standard-Definition STB, which can't be upgraded later. So if you're after upgradeability or HDTV you may want to buy the screen and STB separately.

   

• As a built-in part of a PVR (with or without built-in hard drive).

You need to look carefully and compare pricing and features. Don't assume a device will have all the particular features that you want, and make sure it has all the connections you need (eg, SCART, S-PIF, composite, component video, RS-232 and even Ethernet, USB or FireWire).

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