High Definition (HD) TV Information

What is High Definition (HD) TV?
High definition (HD) offers picture quality with four times more detail than standard definition (SD) TV delivering vibrant colour, stunning detail and incredible depth. It’s the ultimate way to watch your favourite movies, TV programmes and sporting events and it’s going to blow you away!

High definition television, or HD TV, is a new standard that delivers higher picture quality and better sound than traditional TV technology. Put simply, older flat screen TVs support current standard definition TV broadcasts, DVD players & games consoles but they can't reproduce the higher picture quality of the new generation high definition programming.

How Does High Definition (HD) TV Work?
HD TV or high definition television offers the highest picture quality available today. Instead of using the conventional 625 lines to plot a TV picture, HDTV uses 720 or 1080 lines. In addition, the pixels in each of those lines are closer together. This results in a hugely improved picture quality, clarity and colour definition. HD also uses millions more colours than SD TV, increasing the richness and intensity of everything you watch. Most HD programmes and movies are also created with cinema-style surround sound that you can experience in full with a compatible surround sound system.

Resolution Differences - 720p, 1080i and 1080p
There’s lots of talk about resolution, but... what does it all mean?

HD TV broadcasts currently come in two formats – 720p and 1080i

720p - The first resolution format is 720p ("p" stands for progressive), which is an image comprised of 1280 lines along the horizontal by 720 vertical lines. Scanning is done by painting a line of pixels before the next one is painted. Because of the sequential scanning, 720p is better able to handle motion and is actually superior to 1080i for that reason.

1080i - The second is 1080i, which measures 1920 x 1080 lines and is displayed as two fields that are interlaced. Interlaced scanning "paints" the picture on the screen firstly by filling in all the odd-numbered scan lines and then filling in all the even-numbered scan lines. Done very quickly, the eye only sees one picture on the television. You get a bit more detail with 1080i but the interlaced image is not as smooth as a progressively scanned one

1080p - Finally, you’ve got 1080p – the ultimate high definition resolution. 1080p is a progressive scan in which all the pixels are displayed at any one time, in the same way as 720p yet with a higher resolution of 1920 pixels by 1080, essentially providing a better, smoother picture.

Many believe 1080p is the ultimate resolution format since it combines the best attributes of 720p and 1080i resolutions to create the sharpest picture yet. However, it’s worth noting that the 1080p format is not currently used by broadcasters and therefore the only way to view true 1080p content currently is via an HD DVD Player, Blu-ray Player or PlayStation 3.

1080p LCD and plasma TVs are currently more expensive than similar sized 720p and 1080i screens however, they are becoming increasingly more common. Look out for the full HD logo on 1080p LCD and plasma TVs.

What Is HDMI/DVI?
It’s necessary for a HD ready TV to have either a HDMI or DVI connection in order for it to receive a digital signal.

HDMI - A High Definition Multimedia Interface (HDMI) cable is an all-digital connector that can carry high definition video and several digital audio channels all on the one cable.

DVI - A Digital Visual Interface (DVI) cable provides a high-bandwidth connection between a video source and a display device.

HD Ready or Not?
The HD ready logo appears on all TV screens and projectors that are compatible with HD TV signals. All TVs on the market featuring the HD ready logo are able to produce at least a true 720p image.

HD Ready screens must meet the following specification:
Minimum 720 vertical lines (the latter figure when a resolution is written out, e.g. 1280 x 720)
Analogue component video and either DVI or HDMI inputs
Support for HDCP content protection
Able to display 720p (1280 x 720 at 50Hz and 60Hz progressive)
Able to display 1080i (1920 x 1080 at 50Hz and 60Hz interlaced)