Number three is interesting because, as mentioned before, the devil is in the detail. The thing to remember here is that an HD Ready television only has to accept both 720p and 1080i signals, but it doesn’t have to be able to display the 1080 lines of information for the latter format. This means that if your HDTV has a resolution of 1,366 x 768, it will downscale the 1080 signal to 720 lines and display it, since it physically doesn’t have enough lines. I’ll come back to resolutions and standards in a minute, but for the moment let me finish explaining the HD Ready requirements.

Number four stipulates that the digital interface must be HDCP (High-Bandwidth Digital Content Protection) compliant. Again I’ll go into more detail about HDCP a bit later, but ensuring that a TV has this feature means that any copy protected source material can be displayed without issue.

720p & 1080i

As I mentioned when talking about standard definition video, traditionally TV pictures have been delivered in an interlaced manner. This means that each full frame of video is split up into two halves made up of odd and even lines. However, a better way to deliver video is to display each frame as a whole, therefore avoiding the frame mismatch that can occur with an interlaced signal – this method of video delivery is called progressive.
 

With this in mind, there’s a fair amount of debate over which gives better image quality, 720p or 1080i – the argument being that even though 720p has fewer lines, the fact that they are delivered as a whole frame potentially makes for a better image. However there is one very important factor that discounts that argument – both LCD and plasma panels are progressive by default. In fact since the vast, and I mean vast majority (in Europe at least) of high definition TVs are either LCD or plasma based, you can’t help but get a progressive picture.

 

Let me elaborate on this a little. As already mentioned, a CRT television draws an image in two passes by scanning from the top left corner of the screen to the bottom right, but both LCD and plasma TVs are fixed pixel devices, so there is no scanning involved. This means that even if you wanted your LCD or plasma high definition TV to display an interlaced image, it couldn’t.

What about if you feed it a 1080i signal? That’s a good question, but one that’s easily answered. If you pump a 1080i signal into an LCD or plasma TV, the television de-interlaces the signal before displaying it on the panel. So, even though the signal being fed to the TV is interlaced, the actual footage displayed on the panel will be progressive. Therefore a 1,920 x 1,080 panel showing 1080i content should look superior to a 1,366 x 768 panel showing 720p content, while pumping a 720p signal to a 1,920 x 1,080 panel should also look less impressive than when that same screen displays 1080i content.
 

 

Now, before all those readers who have bought 1,366 x 768 HDTVs start to cry, there’s more to a great high definition picture than resolution alone. Some of the best quality high definition pictures right now can be seen on TVs with only 768 lines, because the image processing in those sets is so good. In fact it’s worth remembering that you could look at two HDTVs from different manufacturers but using the same panel, and the resulting pictures could be entirely different due to the proprietary image processing that each manufacturer implements.

One thing’s for sure though, traditionally an HDTV with a 1,920 x 1,080 panel would cost you significantly more than a similarly sized 1,366 x 768 model. But that changed recently with the launch of the Toshiba Regza 42WLT66, which offered a Full HD 1,920 x 1,080 panel at a stunning price point. Let’s hope that this is a sign of things to come.

What about 1080p?

There’s a lot of talk going round at the moment about 1080p compatibility and the fact that current TVs don’t support this standard. It’s true that current HDTVs can’t support a 1080p input, but this really shouldn’t be anything to worry about. As I mentioned in the last page, if you feed an LCD or plasma TV a 1080i signal, it will de-interlace that signal and present you with what is essentially a 1080p picture.

Theoretically, de-interlaced 1080i footage should look identical to native 1080p footage as long as no post processing steps are applied during the original conversion process that could degrade the quality. It’s also worth remembering that even movies that are shot digitally in a 1080p 24fps format will need to undergo some conversion to meet the 25fps PAL standard or the 30fps NTSC standard.

There are also the issues of bandwidth and processing power. A 1080p 50Hz signal is going to use significantly more bandwidth than a 1080i 50Hz signal. Of course you could reduce the amount of bandwidth by implementing a high compression codec like h.264, but then you’re going to need some pretty beefy hardware to decode the video once you receive it. This makes it highly unlikely that we’ll see 1080p content via broadcasters, although that doesn’t mean that it won’t become available via distributed media like Blu-ray or HD DVD.

Ultimately though, as more and more movies are shot digitally in 1080p (Star Wars Episode III: Revenge of the Sith was shot in 1080p24), the demand for source devices that output 1080p and HDTVs that accept 1080p natively will grow. Whether this should sway your buying decision now is debatable, but ultimately it depends on how long you're willing to sit on the fence.

HD DVD & Blu-ray

Scary as it may sound for consumers, I’m afraid we’re in for another format war over the next few years. After the whole confusing debacle of DVD-RAM vs. DVD-RW vs. DVD+RW, it seems like the technology industry hasn’t learned and once again consumers will be faced with two competing formats, both of which are claiming to be the next generation optical format.

Right now it’s impossible to say which format will win out, with masses of industry support for both. Blu-ray has the majority of the consumer electronics market behind it, while HD DVD has the support of the DVD Forum and backing from Toshiba and NEC. But the format has got a real shot in the arm from the fact that both Microsoft and Intel are backing it over Blu-ray.

I’m not going to go into excessive detail here about HD DVD and Blu-ray since I’ll be covering this in a separate feature, but I will touch on the basics. The basis of both these formats is that they offer high enough capacity to store high definition media. Whereas a standard DVD disc can store 4.7GB per layer, an HD DVD can store 15GB, while Blu-ray can manage a whopping 25GB. It’s this extra capacity that the Blu-ray consortium will cite as a clear superiority for the format, especially since Sony has already achieved eight layer engineering sample discs with a capacity of 200GB! The current theoretical limit on HD DVD is three layer, offering a maximum of 45GB per side, which is still 5GB short of the Blu-ray dual layer capacity.

There is of course the question of whether the extra capacity offered by Blu-ray is indeed necessary though. After all if 30GB gives you enough space to store a high definition movie encoded at a decent bit rate, with multiple soundtracks, do you really need 50GB or even 200GB? The Blu-ray camp will tell you that the extra capacity will mean a whole host of extra features like director’s commentaries, behind the scenes features, documentaries and the like, but I wonder how many average consumers would ever watch the extra features on a DVD, let alone watch hours upon hours of extras on a Blu-ray disc. I’m fairly certain that most DVD buyers will watch the movie and never once consider listening to a feature length commentary. Don’t get me wrong, I know that some people love the extras, myself included, but I think that we’re the minority.

HD DVD & Blu-Ray

The answer to every consumer’s dream would be a drive/recorder that can use both formats, but although there has been much talk around this subject, nothing has been officially agreed yet. However, the good news is that Ricoh has recently announced a laser technology that will read both formats, which is a definite step in the right direction. But I really don’t think that it’s technology that’s standing in the way of unified hardware, more the millions of pounds spent on marketing each format.

You can expect to see lots of Blu-ray and HD DVD hardware start to appear over the coming months. It will no doubt be very expensive, and the chances are that the early adopters will carry the burden while manufacturers try to claw back some of their R&D costs.

HDMI & HDCP

HDMI or High Definition Multimedia Interface represents the natural progression for AV equipment. In the PC industry the switch to a digital interface between computer and monitor happened a long time ago when LCD panels became prevalent. However, the ongoing use of CRT for televisions meant that a digital to digital link between source and display was not possible, but now that LCD and plasma screens have become the norm, a digital link is the obvious choice.
 

HDMI is very similar to DVI except that it can carry digital audio as well as video. You may well find early HDTVs with a DVI port instead of an HDMI port – this won’t be a problem as converters are easy to come by, but you will need to connect the audio separately. HDMI can carry up to eight channels of uncompressed digital audio, but to make use of that multi-channel goodness you’ll have to be sending the signal to a surround sound amplifier. That said, if you’re serious about your home cinema you’ll want to hook all your source devices to an amp, and then run a single monitor cable to your TV.
 

Another advantage that HDMI has over DVI is the size of the connector. An HDMI connector is tiny compared to DVI and it also just plugs straight in rather than having screws on either side. Also it can be all too easy to bend the pins inside a DVI plug whereas an HDMI plug is far more robust.

An HDMI port is only half the story though, both your source device and your TV must be HDCP (High-bandwidth Digital Content Protection) compatible. HDCP is Hollywood’s safeguard against high definition piracy. With a digital interface like HDMI, the last thing that Hollywood studios want is for you to be able to make perfect digital copies of its high definition movies. HDCP stops digital copies from being made by encrypting the data stream that travels between source and display, and making sure that both devices are allowed to talk to each other.

Both Blu-ray and HD DVD players will have Ethernet ports, which allow the player to communicate with the manufacturer and movie studios. Software can demand that a player is online before the movie is played and if the studio recognises the player as being compromised as far as copy protection goes, it can revoke the player’s licence to play the content. The subject of your movie player constantly communicating with third parties and logging your viewing habits is somewhat concerning and something that I will cover in greater depth in my future Blu-ray and HD DVD feature.
 

If an HDCP enabled source device recognises that the display it’s connected to isn’t HDCP compliant it may choose to either downgrade the resolution of the video (thus negating the point of HD) or even not show the video at all. Thankfully it’s pretty hard to find an HDTV that isn’t HDCP compatible these days.

Just to confuse matters, the HDMI 1.3 standard was recently announced and should be appearing on devices towards the end of the year. The new standard significantly increases the available bandwidth, thus enabling more detail (both visually and audibly) to be sent down the cable. Does this mean that you shouldn’t buy any equipment that’s using the current HDMI 1.1 standard? Probably not – one thing I’ve learned is that there is always something better coming down the line, but you can’t sit on the fence forever.

Sky HD

With Blu-ray and HD DVD hardware and software yet to launch in the UK, the only widely available source for HD content is Sky’s new HD service. Like every new technology, Sky’s latest box of tricks doesn’t come cheap, but the big question is whether it’s worth the money.
 

Just getting up and running with Sky HD is going to set you back £299, because that’s how much you’re going to have to pay for the box. The Sky HD box is manufactured by Thomson, a company with a pretty decent heritage when it comes to AV equipment. The box definitely looks good, finished in black and silver, and should complement your current AV line up.

The rear of the Sky HD box has an impressive array of connectors, including both HDMI and component video. Interestingly, the engineer who installed my box said that the second generation of devices would not have component video, leaving HDMI as the only HD connection option. I also found it very interesting that there’s a SATA port, allowing for external hard disks to be connected to the box – unlike external drives connected via USB, a SATA connected external drive should run as fast as an internal unit.
Like all Sky Digital boxes, the Sky HD box is supposed to be connected to your phone line at all times so that it can receive updates from Sky HQ. I have to say that I’m very surprised that Sky doesn’t allow its boxes to communicate over the Internet instead, since so many households have broadband these days. That said, the inclusion of an Ethernet port at the rear points to Sky adopting this method in the near future, especially since the company is now touting its own broadband service.

There’s also an optical digital output, in case you want to pump your surround sound to an external amplifier that doesn’t have an HDMI pass-through. And finally there are a couple of SCART connections for outputting to a video recorder or second TV.

The Sky HD box has Sky+ functionality built into it, so you can pause live TV, rewind something that you may have missed, or schedule recordings of an entire series so you never miss an episode. There’s 160GB of hard disk space to facilitate recording, but the installation engineer told me that there is almost that much space again but Sky hasn't made it accessible to the customer.

Sky HD

The initial cost of the Sky HD box may seem high, but you are getting a lot of new technology and a whole heap of functionality thrown in, which makes the outlay easier to swallow. However you also have to factor in the ongoing subscription cost, after all if you’ve gone to the trouble of buying a Sky HD box, you’re going to want access to as much HD content as possible, and that means signing up for the premium package. Ticking the box to get you everything will set you back £42.50, plus an extra £10 per month for your HD subscription – so you’re going to have to plan on watching a lot of HD football and movies to justify the cost. Me? I’ve got to review high definition TVs, so I’ve got no choice – honest!
 

But once you’ve got past the cost, once the wait for installation is over and you sit down on your sofa and fire up some HD content, it somehow all seems worth it. Seriously, once you’ve watched an episode of the BBC’s superb Planet Earth nature programme, you’ll never want to watch standard definition again – which is a shame considering you’ve just signed up to hundreds of SD channels as well as the handful of HD ones.
 

 

Sky is well aware that anyone who’s stumped up the cash for the HD service will want to primarily watch HD content, so pressing the red button when in the root menu of the TV Guide will list only HD channels. And this is where I find myself every time I switch my TV on these days – it’s not a case of searching through the TV Guide looking for something good to watch, it’s a matter of watching something, anything as long as it’s in HD. I haven’t watched this many documentaries for a long while.

The Sky HD box does give you the option of copying recorded content to a VCR or DVD recorder, but before you get too excited, any high definition recordings are downgraded to standard definition before the copy process starts.

If there’s one problem with the Sky HD service, it’s that there aren’t enough high definition channels, but I’m sure that this will change over the coming months. But even as it stands I’d say that the service is worth the money, just so that you can get the best from your shiny new HDTV.