High Definition TV in the UK

To watch High-definition TV, you'll need an "HD Ready" TV set . You'll need an LCD, plasma or DLP TV set. Even if you're not planning to sign up to an HD service just yet, consider getting a TV with the "HD READY" logo when buying a new TV.

Your LCD, Plasma or DLP TV set will need to have a minimum resolution of 720 lines in wide aspect ratio. More

Your HD TV will need a different type of connector for connecting to an HD set-top box, Blu-ray player or games console - the connector will either be a DVI (Digital Video Interface) or HDMI (High Definition Multimedia Interface) connection.

HD TVs are available from online retailers including:

• Dixons
• Misco (good choice and handy glossary)
• Comet

You'll also need an HD TV decoder (such as a Sky+ HD set-top box) to watch hi-definition TV.

Sky+ HD Box - High Definition receiver

By 2012, the UK's analogue TV service will be switched off. You'll need a digital TV receiver to continue getting telly.

It's important to note that High Definition is nothing to do with the Digital Switchover. You don't need an HD TV to get digital TV.

More on the switchover can be found at switchhelp.co.uk

Sky Digital is currently leading the field in HDTV in the UK. Here are some facts:

• Sky Digital launched its High Definition satellite TV service in May 2006.
  
  
• Channels: Largest number of HD channels in the UK. The following High Definition channels are available: The free-to-view BBC HD channel, Channel 4 HD, Sky 1 HD, FX HD, Biography HD, Sky Arts HD, Luxe TV, Sci-Fi HD, Sky Real Lives, nine Sky HD Movies channels, 3 Sky Sports HD channels, Rush HD, Eurosport HD, Discovery HD, National Geographic, History HD, Crime HD plus Sky Box Office HD movie channels. See the full list here.
  
  
• The Sky+ HD box records up to 80 hours standar or 30 hours of HD, and the box supports 720p and 1080i
  
  
• How to get: To get Sky+ HD, you'll need a Sky+ HD Box (priced £49), to pay the monthly HD subscription of £9.75, and to have an HD-Ready TV set. More at www.sky.com
  
  

Sky+ HD featured in our Show 23 of FrequencyCast, our online radio show

HD is being offered by cable TV firm Virgin Media.

Originally under Telewest, the High Definition service launched in March 2006. Content is supplied over their cable network.

• Content: As of 2008, there are only 3 channels available - BBC HD channel, and for an additional subscription fee, there's Sky Movies HD 1 and 2. On-demand HD content is available though, including Movies on Demand and TV choice, with full series such as Lost.
  
  
• How to get: To get Virgin Media High Definition, you'll need the Virgin Media V+ box. Installation of the V+ box costs £150. Additionally, there's a monthly subscription for the V+ service (£5 a month, or free if you're on the XL package)
  More on Virgin Media's site

In May 2008, the Freesat service launched. This service is operated by the BBC and ITV. It offers a range of free channels, plus HD content without a subscription. More on Freesat

• Channels: At launch, the BBC HD was available. In June 2008, the ITV HD channel started offering a few hours a day of content exclusively on Freesat. More HD content is likely to appear on Freesat in the future. See the full Freesat channel list here.
  
  
• How to get: To get Freesat, you'll need a High Definition receiver (from £120) and a satellite dish (installation typically £80). See our Freesat box list. More on our Freesat page
  
  

BT Vision is a digital TV service offered to BT Total Broadband customers throughout the UK.

THe BT Vision set-top boxes support High Definition. There's no live HD content on BT Vision, but you can download HD movies and TV shows over Broadband onto your BT Vision+ box, to watch on your TV in HD.

More details at btvision.bt.com

In April 2008, UK Regulator Ofcom announced that we can expect up to four high-definition digital TV channels to be delivered via a TV aerial on Freeview as soon as 2009.

Three of the four channels will be BBC, ITV and Channel 4. It won't be until 2012 that all of the proposed four Freeview HD channels become available across the whole UK.

It's expected that viewers will need a new Freeview box to get HD. Existing Freeview boxes will continue to work for non-HD Freeview channels.

More on Freeview HD.

The most common connector for High Definition equipment is the HDMI connector, pictured below.

An alternative, is the slightly older DVI connector (Digital Visual Interface), pictured below:

You also get high definition using component cables - note that this is analogue, and component does not carry the audio.

Looking for high-definition cables and adapters, such as HDMI leads, or HDMI to DVI cables? Try TV Cables or Maplin Electronics

We recommend the Nikkai Pure range (high-quality, oxygen-free copper) for minimal signal loss.

High definition TV is transmitted in two different hi-def formats:

• 720 progressive - Each image is made up of 1280 pixels on 720 horizontal lines. The 'progressive' bit refers to the fact that each line is drawn individually to build up the picture.
• 1080 interlaced - Each image is made up of 1920 pixels on 1080 lines. 'Interlaced' refers to the fact that the image is split into two 'fields' that are scanned separately, odd-numbered lines, then even-numbered lines.

1080i offers more detail than 720p, but interlaced images aren't as smooth as images that are rendered progressively. The format of an HD picture depends on how the programme maker recorded the programme.

Set-top boxes such as the Sky+ HD box support both 720p or 1080i HD formats, switching according to the programme's format, and a high percentage of HD-Ready TV sets support 720p and 1080i (but check before you buy).

For a TV or HD product to be certified as "HD Ready", it has to meet the following requirements:

• Have a minimum native display resolution of 720 physical lines in wide aspect ratio.
• Accept HD input via: Analogue YPbPr1, and DVI or HDMI
• Have HD capable inputs that accept 1280x720 @ 50 and 60Hz progressive (“720p”), and 1920x1080 @ 50 and 60Hz interlaced (“1080i”)
• The DVI or HDMI input must support content protection (HDCP)

You can find full details of use of the "HD Ready" logo at http://www.eicta.org/index.php?id=32&id_article=50

Question from a site visitor: "Do I need a special aerial for LCD HD ready tv sets?" (Dec 2006)

At the time of writing, HD TV content is available from Sky TV (using a satellite dish) or Cable TV - it's not possible to get High-definition content via a TV aerial yet. When (and if) HD content is made available via Freeview, it's likely that if your aerial is good enough to get Freeview, it'll be fine with Freeview High Definition content.

Here's a quality question from site visitor Peter Denton: "Please can you tell me why some programmes transmitted in HD are sometimes fantastic, and other times you would never know it was HD. Sky football matches are a good example.... sometimes great , other times not."

Note that HD denotes the number of horizontal lines a picture has (minimum 720, compared with 576 for standard definition). Just because content is "in HD", there's no guarantee that it's pin-sharp and perfect. A number of factors can affect HD quality:

• Sky HD boxes support two different HD formats 720p and 1080i. More.
• Compression - HD uses a lot more bandwidth than standard definition, and the signal is compressed (Sky use MPEG-4 compression for their HD service). Different compression ratios can be used. Fast-moving images (common with sporting events) make compression artifacts more visible.
• Not all content on HD TV channels is true HD. Some content is standard definition that's been 'upscaled' to the larger number of horizontal lines used on HD.
• Recording techniques - Different broadcasters record, edit and transmit their content differently, and it's not always perfect.
  
  

You may find that your HD set-top box has both an HDMI socket and a set of Component sockets - but which is best?

Well, they both are capable of transmitting High Definition. HDMI is 'digital', so is less prone to interference over long distances. HDMI also carries the audio. Component is analogue and doesn't carry audio. For more on this, read this article.

If youir TV set doesn't have enough HDMI sockets - you can get various adapters and switch boxes.

At the basic end is a 2-into-one selector lead (the HDMI Selector from Maplin, and there are various other 2-way, 3-way and 4-way selectors available from TV Cables or Maplin Electronics.

When looking for a TV, you may see Contrast ratios quoted at you. The contrast ratio is the difference between black and white. Basically, the higher the ratio, the more difference between black and white the TV supports.

In Show 15 of our podcast, we heard from forum visitor Linus, who pointed out the following... "sales folk are keen to push 'bigger is better', but unless you watch your telly in a pitch-black room, you could be wasting your money going for big-number ratios. In a living room with moderate ambient light, anything higher than a 500:1 ratio wouldn't be perceivable by the eye."

For more on choosing a telly, see our podcast's TV Set page, and listen to our audio guide in Show 25.