Near HD Toshiba LCD TVs
You will already be familiar with standard definition television and you will have heard about high definition, but what about near High Definition?
This is a term that is used by Television manufacturers for a system that enhances the quality of Standard Definition pictures on televisions to near High Definition.
Is there any need for a Near High Definition Television?
Whilst there is an increasing amount of HD content available via Sky and Freesat it isnt possible to watch all available programs in High Definition. The only other sources of HD are Blu-ray and downloads from the internet. Furthermore if you arent prepared to pay a monthly subscription or pay for Blu-ray discs then the choice is limited to Freesat or a small selection of On Demand programmes and movies from Virgin Media or Tiscali. With such a limited choice of High Definition content the television manufacturers believe there is a case for near High Definition televisions that upscale the picture to allow you to make the most of your HD television.
Standard Definition Broadcasts
A TV picture consists of 1000s of little cells known as pixels. Broadcasts in the UK use the PAL system which in standard definition has 576 horizontal lines of 768 pixels across the screen or 768 x 576 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 number of pixels that make up a picture is known as the resolution. So a television with more pixels will have a higher resolution. Generally the higher the resolution is on a television the sharper the image that it can produce. Televisions with a high resolution are known as High Definition televisions.
At present UK broadcasts of HD content are at 720p (1280 pixels x 720 pixels) or 1080i (1920 pixels -1080 pixels) resolution. To benefit from this you will need a television that is at least HD Ready with 720p (1280 pixels x 720 pixels). Alternatively you can buy a Full HD Ready 1080p (1920 pixels x 1080 pixels) television although there arent any broadcasts that will allow you to benefit fully from this specification. The only source that is available is either Blu-ray disc or downloads via the internet.
With suitable source material a Full HD Ready 1080P TV has a picture resolution thats five times higher than a SD TV which explains why the picture is so much better.
On TVs that have Near HD they use an upscaler to transform an SD picture into 1080P.
An Upscaler transforms an input signals resolution to the resolution of the TVs screen. Therefore if you have an HD Ready TV (1280×720 pixels) or a Full HD 1080P TV (1920×1080 pixels) and you watch Freeview or a DVD that has a resolution of 768×576 pixels the TV has to upscale the picture to fill the different resolution TV screen. If television didnt have a digital upscaler the image wouldnt fill the screen and there would be areas of the screen that would be black and unused due the resolution mismatch of the HD TVs native resolution and the resolution of the source.
The upscaling process is done by the TV using a digital video processing chip which interlaces the input signal and then the advanced algorithms and filters interpolate the picture by creating the missing lines and pixels that are required to fill the screen. This process matches the input resolution with the TVs native resolution.
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.
Different sources of programmes and films are available at different resolutions that dont match the resolution of a television screen. Ordinarily a TV that received sources with a resolution that is different to its own native resolution would have areas of the screen without any picture information on it. To get around this problem all LCD and Plasma televisions have an upscaler that matches the source resolution to the TV screen so that the image fills the screen. A Near High Definition TV has a much powerful upscaling processor chip that is capable of producing a better quality upscaled image than ordinary TVs.
The higher quality upscaling chip employs sophisticated software algorithms that approximate how the additional created pixels should look in the upscaled image. However this approximation isnt as good as a Full HD sourced image where the TV doesnt have to guess what the extra pixels look like. Any approximations will sometimes be inaccurate but an educated guess.
Toshiba have a range of TVs that use the cell processor from the Sony PS3 to upscale the image to the Near HD 1080P resolution. Toshiba have called this feature Resolution + which is featured in their ZV series of TVs. This feature vastly improves the picture quality of a SD picture source.
The image cell processor compares adjoining images which it merges the detail of to improve the image detail. This gives an image that is lucid with rich colours. The extra detail means the image has sharp edge detail with noticeably reduced 3 D noise. Also the blue and green colours are enhanced to compensate for potential clarity losses that can result from upscaling. Also the contrast is improved in dark scenes but the light areas are still as bright. The combined effect of all of these enhancements is that an SD picture is crisper and with sharp edge detail and better texture whilst the flat areas are unchanged.
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.
Should you buy Near HD TVs and DVD Players?
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.
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