Near HD LCD Televisions

Every one is already familiar with standard definition television broadcasts. Most people have also heard of high definition but few have heard of Near High Definition.

A Near High Definition is new type of television that manufactures have launched to enhance a SD picture so that it is Near to High Definition.

Why do you need a near High Definition Television?

High definition broadcasts arent available on normal terrestrial analogue or digital broadcasts such as Freeview. The only broadcaster that provides limited HD content free of charge at present is the BBCs and ITVs Freesat broadcasts. Sky has the most HD channels but you have to pay a monthly subscription charge. The chances are that you will still watch standard definition broadcasts because not all programmes are available in HD. Alternative sources of HD are Blu-ray discs, download from the web or On-Demand services from Virgin Medias Cable serve or Tisclai. Because the options for watching HD are restricted producers believe that upscaling televisions with Near High Definition pictures will allow people to take advantage of the potential of HD television sets using a SD source.

What is Standard Definition?

The picture on an LCD or Plasma television is made of many thousands of pixels. In the UK the television system is known as Pal which is broadcast with 576 hozontal lines of 768 pixels (576×768 pixels).

A moving television picture is created by showing a series of 25 still frames every second. Each frame contains a still image with slight changes from frame to frame. Each of these frames is divided into two fields, one of which contains all of the odd lines and the other all of the even lines. The displaying of a moving picture using these fields is known as deinterlacing where the two fields of a single frame are combined to form a full frame. The odd fields and the even fields are alternately painted or scanned on to the TV screen each at a rate of 25 fields a second or 50 fields a second when combined. This is where the term a 50 Hz picture has comes from.

The resolution of a television is determined by the number of pixels that make up the screen. The more pixels there are in a picture the higher the resolution and usually the sharper the picture that it is able to display. TVs that have a high resolution are called High Definition (HD) TVs.

All UK high definition broadcasts are either at 720 p (1280pixels x 720pixels) or 1080i (1920pixels x 1080pixels). You will need a television of a specification of at least HD Ready which will be able to display a 720P broadcast. There arent any broadcasts of 1080 P ( 1920pixels x 1080pixels ) material in the UK at this moment in time. To take advantage of the full reolution of a 1080P tv set you will have to view either Blu-Ray discs or downloads from the internet.

A Full HD Ready 1080p television has a picture resolution that is about 5 times the resolution of a Standard Definition television. This is why with suitable source material a Full HD television has such a stunning picture.

So how are near High Definition images created from Standard Definition? A process known as upscaling is used to create a near HD image. But what is upscaling?

Upscaling or Upconverting is the process of converting a signal from one resolution to another. So when you view a DVD or Freeview with a resolution of 768 – 576 on a HD Ready Television or a Full HD 1080p Television with a resolution of 1920 x 1080 if there wasnt any digital upscaling done by the television then the picture wouldnt fill the screen and there would be large areas of black. The reason for this is that the resolution of the DVD or Freeview isnt the same as the native resolution of the HD television screen so many of the pixels wouldnt be used by the smaller image.

The upscaling in a HD TV is performed by a video processing chip which first interlaces the fields of the frames that create the picture using complex digital algorithms and filters that interpolate the picture by estimating what the extra pixels and lines should look like. This is done to match the incoming signal resolution with the native resolution of the TV.

The quality of the upscaled image thats displayed will be determined by the quality of the upscalers processing chip, other electronics and the screen. The source signal quality will also be very important in determining how the internal electronics manage the picture and how they well they display it.

An upscaler is required by all LCD and Plasma TVs so that they are compatible with the various source resolutions that they may be presented with so that they fill the native resolution of the screen. It may seem that the Near HD TVs arent doing anything different to any other LCD or Plasma TV but it is how they do it that is different. The Near HD TVs use a more powerful upscaling processor chip which means that they are much better at upscaling than ordinary TVs.

No matter how sophisticated the algorithms are that guesstimate how the additional pixels should look an upscaled SD image isnt as good as an actual true 1080P HD picture.

Toshiba has a near HD upscaling technology called Resolution + which they incorporate in their ZV range of televisions that they say will vastly improve the quality of a Standard Definition picture. They use the powerful upscaling cell processor that is used in the Sony PS3 which upscales any image to 1080p resolution.

The cell processor compares neighbouring frames and aggregates the pixel detail to raise the definition of the picture. The effect of this is that the picture has sharper image edges with subdued 3-D noise. Furthermore the colour palette is more lifelike because the blue and greens are improved to minimise the loss of clearness that can be caused by an upscaler. Also due to the contrast being enhanced the dark areas are even darker but the light areas sustain their luminance. The SD images are crisp and rich and have sharp edge detail with improved texture however the flat areas are not changed.

Upscaling Near HD DVD Players

Some DVD Players have a feature known as progressive scan that combines the deinterlaced images of the two fields so that they are displayed at the same time to producing the full frame. Progressive scan produces smoother movement, higher vertical resolution and no interlacing artifacts e.g. line flicker. Whilst progressive scan does improve the picture quality it doesnt generate more lines and pixels with more detail as an upscaling DVD player does.

An upscaling DVD player uses the same methods as an upscaling television. There are a number of upscaling DVD players from different manufacturers but non of these work in the same way as the Toshiba XDE model which deinterlaces the picture before upscaling it from 576i lines to 1080P Near High Definition quality. The picture on the Toshiba upscaling DVD player is improved with images that are extra detailed with brilliant colours and enhanced contrast by employing the methods used on the Toshiba Near HD TVs.

So should you buy a Near HD TV or DVD Player?

Is Near HD as good as true 1080P Full HD? No, because it doesnt matter how sophisticated the digital upscaling process is it cant make a SD image the same as a HD image because it has to guess what the missing information is. However the Near HD feature does enhance the picture so that it is closer to the HD image than a SD picture. Whether you should buy an upscaling Near HD TV will depend on how much you are willing to pay to receive HD broadcasts and Blu-Ray Discs, the type of programmes that you watch and how important it is for you to have the best picture possible from whatever source. If you dont buy Blu-ray discs and you dont want to pay a monthly subscription charge to Sky for HD then there isnt much choice available from the BBCs and ITVs Freesat therefore a Near HD product will be right for you. Even if you do watch Sky HD it will work on 720P and also 576i and 480i for standard definition broadcasts and video games which will be upscaled to 1080P.

A further benefit of purchasing a Near HD TV is that if more free HD content becomes accessible in the future or if you subscribe to Skys HD service then you will not need to buy a HD TV because the Near HD TVs are also Full HD 1080P TVs. In the United Kingdom the only Near HD products that are currently available are made by Toshiba but other products will be launched by alternative manufacturers soon.

Armadeus Cornelius is an AV enthusiast and expert with nearly 20 years experience in consumer electronics. His website at www.digitaldirect.co.uk offers ‘Near HD’ TVsand a large selection of AV products at low prices. For your convenience you may also find these links useful toshiba upscale dvd player and toshiba online sales