What is HD?

By James Pickard - Tue 11th Mar 2014 Guides

High definition TV offers viewers enhanced picture and sound quality, improving the whole experience and making movies, sport and TV much more vivid and crisp. Read our detailed guide about HD TV.

What is HD?

High-definition, or HD, is the term used to describe a form of TV broadcasting which provides extremely high quality picture and sound.  A better TV that is HD-ready must be used in order to watch programmes broadcast in HD quality.  Not everything is available in high definition, but different channels and providers are usually very focused on advertising which content can be in the superior format, so it’s easy to find out which channels and programmes have the HD treatment.

For those of you interested in the more technical explanation....

The HD signal contains information that is decoded into pictures and sound; where a standard definition (SD) broadcast on digital TV would have between 500 and 600 horizontal scan lines of display resolution, the high definition (HD) broadcast will have at least 720, or, in the case of Full HD, 1080.

HD Benefits

High definition TV gives you a crisp, vivid image combined with clearly defined sound quality.  Digital TV is a step up from analogue, giving a much more impressive picture, and this transition to digital has opened the door for HD broadcasting, which makes further improvements to your viewing.

The image is clear, bright and striking thanks to the higher resolution, and HD programmes can have up to five times more detail than content broadcast in standard definition.  The audible quality of the surround sound also improves, as HD TVs are equipped to provide optimum audio performance, which means it will be clear and crackle-free.

HD Programmes

Not everything is broadcast in HD (or at least not yet), but many major channels now have an HD alternative showing many of the same programmes but in the higher quality resolution.  BBC, ITV, Channel 4 and Channel 5 all have HD channels, as do many other channels available through subscription.

If you have access to Sky Sports, then you can also watch Sky Sports HD, which will show the same popular sporting events as the standard definition station, but with crisper visuals and better sound.  Many of the movie channels on digital TV have HD versions too, and the number of channels offering the HD alternative is on the rise.

HD Equipment

In order to watch HD channels you will need an HD-ready TV.  Standard TVs, no matter how expensive, will not be able to give you the higher resolution needed to make the most of high definition.  You will also need an HD receiver which will decode the information and turn it into high quality pictures and sound.  One of these would be built into a provider’s own brand HD box, or it may be integrated with the HD TV.

You will also need an HDMI cable which will connect the box and TV.  It is not needed if the TV is integrated with the receiver.

You will of course need a digital TV provider in place, and the available HD channels can depend on which provider you choose.

HD Cost

If you are a digital TV subscriber, your provider may offer you the HD channels at a discount price, or even free.  This depends on which offers are on at the time.  There are always deals and offers which are incentives to join, and, with HD proving increasingly popular, the improved format is a good selling point.  If you just get the free-to-air channels, then you will only get the free-to-air HD channels as well, but you will still need the equipment listed above.

The price of an HD TV varies; there are so many high street shops and online retailers that stock them, so it’s best to just shop around for a good deal.  You will also want to decide on the capability of the HD TV you buy; an HD-ready TV could be 720p, but the higher tech models are Full HD, which means 1080p or 1080i.  For more detail on this, see below.

HD ready vs. Full HD

The two types of HD are HD-ready and Full HD; both deliver high quality pictures and sound, but one is more advanced with increased resolution.

HD-ready delivers 720 horizontal lines of information in a frame, which is far higher than that of a standard definition broadcast, and this will be great for watching HD TV.  Full HD is the step up, with 1080 horizontal lines per frame.  This delivers striking picture quality, and is the optimum choice for watching films on Blu-ray.