TV jargon buster Jargon explained A – I

3D TV - manufacturers plan to launch 3D-ready TVs in 2010

3DTV HDTVs that can display 3DTV pictures are available from 2010. To watch you'll need one of the new 3D-ready TVs, a pair of 3DTV glasses - and some 3D content to watch. Sky are due to launch a 3DTV service in 2010 that will work with its current Sky+ HD boxes.

3D technology isn’t new. Two cameras are used to record slightly different perspectives of the same image, which are displayed on screen as a double image. Polarising glasses filter a different image to each eye, creating the illusion of 3D.

5.1 An arrangement of five speakers used to create surround sound (preferable to the inferior 2.1 system). Check our independent home cinema system reviews for the best in surround sound.

100Hz and 200Hz processing Most TV pictures are broadcast or recorded at 50Hz – that’s 50 fields or 25 frames per second. In an attempt to manipulate the picture and create the illusion of smoother motion, many LCD and plasma TVs feature 100Hz processing software. This basically doubles the number of frames on screen. This can make motion seem smoother, but sometimes looks too artificial.

The 600Hz logo found on some plasma TVs.

600Hz processing Instead of increasing the frame rate in the same way as 100 or 200Hz models, 600Hz TVs rapidly flash the pixels (that make up each frame) on and off in an attempt to create the illusion of smoother movement. Technically known as ‘sub-field’ processing, it’s found on some plasma TVs.

1080i and 1080p There are two main types of high definition (HD) picture – 1080i and 1080p. HD TV is broadcast in 1080i, but high-definition Blu-ray discs are recorded in 1080p, which is marginally more detailed and realistic. This is because on 1080p the 1,080 horizontal lines are scanned progressively, or one after another.

With 1080i even then odd lines are scanned alternately to make up the picture, however the difference is really quite subtle. 1080p is not broadcast, because the pictures would simply take up too much space, or bandwidth. Check our Blu-ray player reviews to find the best models for watching 1080p.

Analogue tuner This picks up the old-style analogue TV signals for terrestrial channels. These signals are being gradually switched off – the process will be completed in 2012. Go to www.digitaluk.co.uk to see when your area switches. Most new TVs still have an analogue tuner.

The aspect ratio of digital TV is suited to widescreen TVs

Aspect ratio Shape of the screen (width:height). The vast majority of TVs are now widescreen with an aspect ratio of 16:9. Older TVs and some portables have an aspect ratio of 4:3. Digital TV is broadcast in a widescreen format.

Audio description This is an additional narration for visually impaired people that describes significant visual information, such as body language and scenery. The service is available on Sky, Freeview and Freesat. Most new TVs can decode audio description on Freeview.

Auto-format switching It's a good idea to choose a widescreen TV that automatically alters how different broadcasts are displayed – for example, showing standard (4:3) broadcasts with black bands on either side so the images aren't stretched out of proportion. Most widescreen TVs will do this.

Auto power-off If you leave your equipment switched on when not in use, this handy energy-saving feature will switch it into standby after a given period of idleness.

Backlights LCD TVs feature backlights –lamps at the rear of the screen which illuminates the picture. You can alter the backlight’s brightness to manipulate picture quality and save power.LCD TVs

For instance, LCD TVs with an ambient light sensor automatically adjust the brightness of the backlight according to the ambient light in the room, which saves power. Dynamic backlights adjust their intensity according to the content on the screen in an attempt to prevent images looking washed out.

Plasma TVs don’t have backlights – instead, they alter the brightness of the individual gas cells that make up the picture, saving power and creating much the same effect.

Black level control This adjusts the pictures’ black level. This is useful for watching movies with particularly dark sequences, like The Matrix. LCD TV pictures can often look a bit washed out, so any boost from the DVD can be especially helpful.

Blu-ray A high-definition DVD format developed by Sony. A Blu-ray disc can hold nine hours of high-definition (HD) video and around 23 hours of standard-definition (SD) video on a 50GB disc. Blu-ray pictures are recorded in 1080p, which is subtly more detailed and realistic than the 1080i HD broadcast signal.

Bookmarking DVD players with bookmarking let you mark favourite scenes or places in a disc so you can quickly find them again. More sophisticated DVD players let you bookmark several discs, and will ‘remember’ your bookmarks even when the disc is removed.

Component This is a high quality video input made up of three sockets coloured red, green and blue. Also known as YPbPr, it splits the video signal into three separate parts for an improved picture. However, component connections are still not widely used on AV equipment and unlike Scart sockets they do not carry the widescreen switching signal.

Composite input (see video input) 

12,000:1 is not ‘twice as good’ as 6,000:1

Contrast ratio The difference between how dark and bright the picture on a flat-panel TV will go. A higher contrast ratio should mean deeper blacks and whiter whites, with a good range of subtle colour in between. However, it’s not a linear value – so 12,000:1 is not ‘twice as good’ as 6,000:1

CRT Cathode ray tube – the technology behind traditional big-box TVs. Traditional cathode ray tube TVs have now been superseded by chic flat panel models. You can't watch HDTV on the vast majority of traditional TVs. However, picture quality on the best conventional CRTs can still be hard to beat when watching normal TV programmes.

Digital coaxial and optical output If you use surround sound, be careful. There are two types of digital connections - coaxial (wire) and optical (fibre optic). Make sure your surround-sound system input matches the output on either your DVD player, HD TV or set-top box. Both connections can also carry stereo signals.

DLNA DLNA (Digital Living Network Alliance) is an industry-wide standard developed to allow the sharing of digital media - such as photos, videos and music - between computers, mobile phones, TVs and other devices in and around the home. TVs with ethernet ports can often connect to home networks and stream content this way.

DTS Digital theatre system: a surround-sound standard that is used in home cinema systems. The DVD has become the standard method of renting and playing films, but is being superseded by the next generation of 'high-definition' Blu-ray DVDs.

DVD disc types (RW, RAM etc) Not all DVDs are the same. There are several different recording formats – DVD-R, DVD+R, DVD-RW, DVD+RW and DVD Ram – each with slightly different features and capabilities. Check with sales staff to ensure your discs can be played on your new device. All DVD players will play pre-recorded DVDs (those you rent or buy).

DVI input This is the standard digital input used for high-definition video. Unlike HDMI, it cannot carry audio signals.

EPG Electronic programme guides display schedules of the week’s digital programmes onscreen - a bit like having an electronic TV guide at the touch of a button. The style and format of an EPG depends on the particular model of TV, but most show programmes at least seven days ahead, plus a 'Now and Next' option.

Some televisions feature a second EPG called Guide plus+. The Guide plus+ system has a better programme search facility than regular Freeview EPGs, and offers the ability to rank and highlight programmes. However, it’s generally slower to download programme information and includes onscreen adverts, which many may find irritating.

Connect to your home network via the ethernet port

Ethernet port This allows connection to a local home server (a computer network in your house), letting you stream audio and video content straight to your LCD or plasma TV. It’s typically used for DLNA-compliant content or to access the internet on your TV.

Flat-panel display The general term used for LCD , plasma and LED technologies. Check our expert independent reviews to find the best flat-panel TV.

Freesat Freesat is a digital satellite TV service from the BBC and ITV, launched in May 2008. To watch it you'll need a Freesat receiver, a satellite dish and ideally an HD-ready TV. It's basically the satellite equivalent of the digital terrestrial TV service Freeview – once you've paid for the box, dish and installation there are no more ongoing monthly subscription costs. To find the best Freesat box check our independent reviews.

Freeview A service that provides digital television through an aerial. The service is 'free to air', which means that viewers don’t need to subscribe to watch the broadcasts. If you live in a Freeview reception area (if you’re not sure, check www.freeview.co.uk) you can receive signals either through a digital set-top box or PVR.

Digital Freeview tuners integrated in the TV are increasingly common. Virtually all new TVs have a Freeview tuner built in. To watch Freeview HD you’ll need s specific Freeview HD tuner. To find the best Freeview box check our independent reviews.

Freeview HD A free-to-air service launched in 2010, offering all the usual Freeview content plus a handful of high-definition channels. To watch it you’ll need a specific Freeview HD set-top box or IDTV.

HDD Hard disk drive. Familiar to computer users, these devices are now appearing in PVRs and some DVD recorders as a convenient and flexible way of recording TV programmes. The larger the hard-disk size, the more recordings you can store - so an 80GB HDD will give you around 40 hours of recording time. Typically a PVR will give you 40 or 80 hours of recording time.

HDMI is the best way to connect an HD TV

HDMI High definition socket for connecting HDTVs to high definition equipment such as Sky HD boxes, HD games consoles or Blu-ray players. Some standard DVD players also feature an HDMI output. This is a high-definition video socket, which many manufacturers claim will enhance standard-definition DVD pictures when connected to a HD ready TV. Many manufacturers claim that this will enhance standard DVD pictures when connected to an HD-ready TV. However, we’ve found that improvement in picture quality is uncommon.

HD ready 'HD ready' is a labelling scheme introduced by the TV manufacturers' organisation, the European Industry Association for Information Systems (EICTA). The label means the TV has the minimum screen resolution and digital sockets to receive and display a broadcast (1080i) HD picture. Most new HD ready TVs will also process the superior 1080p HD signal.

The official logo

HD-ready 1080p This official logo from EICTA (the same people behind the official HD-ready logo) means the TV will work properly with high-definition Blu-ray DVDs. There are many similar logos about but they don’t guarantee high-definition DVD compatibility. So be careful and look for the exact match.

Hi-fi You can normally connect your TV to a hi-fi stereo amplifier via red and white phono sockets. This is useful if the TV’s in-built speakers aren't quite up to the job. If your TVs has no stereo phono sockets, surround sound and stereo signals can be carried by digital optical and coaxial outputs.

High-definition television (HD TV) HD TV transmits a high-definition TV signal with roughly twice the standard picture resolution as normal standard-definition television. Sky and Freesat (satellite) and Virgin (cable) broadcast HD TV channels. Freeview HD is broadcast terrestrially (via roof-top aerial), though you’ll need a special Freeview HD box to decode the signal. To find out more about Freeview HD, check out our special guide.

To watch HD TV you need access to one of these services and an HD-ready TV. However, not everything on the dedicated HD channels is actually recorded in HD. More programmes are being recorded in HD all the time, but content can be a bit thin on the ground.

IDTV Integrated digital TVs have Freeview, Freesat or Freeview HD tuners built in so you can receive digital TV and radio channels free.

IPTV Internet protocol TV. Many new TVs come equipped with ethernet ports allowing you to connect to the internet. Instead of allowing full internet access, they typically use special software applications, called ‘widgets’, to access different types of content - for instance videos via the ‘YouTube’ widget or photos via the Flickr photo-sharing widget