LED, LCD and plasma TV: HD TV explained Get HD TV ready
Your TV will need a DVI input (pictured) or an HDMI socket
HD-ready TV
Before you can get started with HD TV, you need a television that's 'HD-ready'. This means the TV has the minimum requirements necessary to receive and display the higher resolution HD picture. The vast majority of new large-screen TVs in the UK are now HD-ready.
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HD TV picture formats
HD TV pictures come in two main formats – 1080i and 1080p – depending on the number of horizontal lines that make up the picture and the way they’re broadcast. All HD-ready TVs can display 1080i and in effect there’s not much difference between the two.
HD TV is broadcast in 1080i. This is made of 1080 lines – the ‘i’ means the lines are not scanned one after another, but ‘interlaced’ so all even-numbered lines are scanned first and then odd numbers. The two combine to make a picture.
A 1080p image is made up of 1080 lines scanned one after another, and pictures are even sharper and more detailed, though this improvement is quite subtle. This system isn't used by broadcasters, but is used by the new generation of high-definition Blu-ray DVD players. These players also output 1080i if required.
The humble Scart lead won’t cope with HD TV signals, so a new type of interface and lead has been created called HDMI. To get HD, your TV will need to have an HDMI or DVI socket and be compatible with a copyright-protection system called HDCP, as the movie industry is concerned that people will start to pirate high-quality transmissions. The HD-ready label ensures compatibility with the HDCP system.
HD-ready and HD-ready 1080p
In theory, this logo should mean better HDTV pictures
The HD-ready label means the TV has the minimum screen resolution (of at least 720 horizontal lines) and digital sockets (HDMI or DVI) to receive and display a 1080i HD picture – so they're perfect for watching HD TV from Sky, Virgin, Freesat or Freeview.
Most new HD-ready sets will also support the 1080p HD signal. If the TV does not support 1080p, it simply switches to 1080i.
The HD-ready 1080p logo from EICTA (the same people behind HD-ready) means the TV can process a 1080p signal, but also has a high screen resolution of 1080 horizontal lines (1920x1080). In theory this should mean even better HD TV pictures.
However, in practice, the quality of the TV picture has a lot more to do with the picture processing software that powers the set, rather than just the resolution of the screen. For instance, many of our Best Buy Panasonic TVs have a relatively low screen resolution, but boast fantastic pictures.
Similar-sounding and looking logos such as, HD Full, 1080HD or 1080HD-ready are also common, but be aware that exact meanings can differ between manufacturers.
What does 24fps mean?
The 1080i versus 1080p question is further complicated by something called 24fps (frames per second). It's not unusual for new TVs to sport logos boasting 1080/24 compatibility. This simply means that the TV can process the 1080p signal and display it on screen at 24 frames per second. The HD-ready 1080p logo is a guarantee of this, but most new HD-ready sets will process 1080/24, too.
1080/24 can become an issue if you want to watch Blu-ray movies on your TV. The high-definition discs are recorded at 24 frames per second, rather than the traditional European speed of 25fps. If the output from the player and the refresh rate on the TV screen don't match, the result can be juddery movements on camera-panning or fast motion scenes.
Still confused? Check out our TV jargon buster.
