Most people are aware of High Definition (HD) even if they still have a Standard Definition (SD) television. But now there is another alternative that is called Near High Definition.
Near High Definition is a new feature that television producers have created for raising the picture quality of Standard Definition (SD) broadcasts to a claimed Near HD quality.
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.
The movement on the picture of a television is created with 25 still frames being displayed successively every second. Each frame is split in to 2 fields that each contains half of the lines that form the picture with the even lines in one field and the odd lines in the other field. The combining of the 2 fields from each frame is called interlacing which produces a full frame. The odd and even fields are shown alternately as the picture is painted or scanned on the screen each at a rate of 25 times per second. The combined display rate of the odd and even fields is 50 times a second which is referred to as 50 Hz.
The total number of pixels that a television screen has is known as the resolution. A high resolution or High Definition (HD) picture has more pixels than a Standard Definition picture. HD TVs will generally have a sharper picture, or will be capable of displaying a sharper picture, than a Standard Definition TV.
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.
The quality of the picture of a Full HD 1080P TV compared to an ordinary SD TV is around five times greater than a standard definition and hence the reason for the terrific image quality.
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?
An Upscaler transforms an input signals resolution to the resolution of the TVs screen. Therefore if you have an HD Ready TV (1280x720 pixels) or a Full HD 1080P TV (1920x1080 pixels) and you watch Freeview or a DVD that has a resolution of 768x576 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 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.
All LCD and Plasma televisions have an upscaler to accommodate the different resolutions of various sources so that they fill the native resolution of the screen. What is different about a Near HD televisions is that they use a much more powerful processor in the upscaler that allows them to do a much better job than other televisions.
Whilst advanced software algorithms are able to estimate what the extra pixels should display in the upscaled picture it isnt able to turn a Standard Definition image in to a genuine High Definition picture.
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 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.
Should you buy Near HD TVs and DVD Players?
Obviously an upscaled SD 576 line picture is not as good as a 1080P Full HD picture no matter how much digital processing is done. Nonetheless there is no doubt that a much better upscaler in a television produces a noticeable improvement in the picture quality so that it is closer to 1080P picture. A Near HD TV makes even more sense if you arent willing to pay a monthly charge for HD from Sky, Virgin Medias Cable, Tiscalis Service or Blu-Ray discs. Even if you opt for Freesat there is a limited amount of HD channels available so your choice of programmes is limited. Because HD isnt freely available, especially with out paying for it, a Near HD TV is worth considering that will produce an improved picture with virtually any content including 480i, 576i, 720p as well as DVD, Standard Definition Broadcasts and computer games. With all of these sources the picture 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. - 32388
Near High Definition is a new feature that television producers have created for raising the picture quality of Standard Definition (SD) broadcasts to a claimed Near HD quality.
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.
The movement on the picture of a television is created with 25 still frames being displayed successively every second. Each frame is split in to 2 fields that each contains half of the lines that form the picture with the even lines in one field and the odd lines in the other field. The combining of the 2 fields from each frame is called interlacing which produces a full frame. The odd and even fields are shown alternately as the picture is painted or scanned on the screen each at a rate of 25 times per second. The combined display rate of the odd and even fields is 50 times a second which is referred to as 50 Hz.
The total number of pixels that a television screen has is known as the resolution. A high resolution or High Definition (HD) picture has more pixels than a Standard Definition picture. HD TVs will generally have a sharper picture, or will be capable of displaying a sharper picture, than a Standard Definition TV.
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.
The quality of the picture of a Full HD 1080P TV compared to an ordinary SD TV is around five times greater than a standard definition and hence the reason for the terrific image quality.
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?
An Upscaler transforms an input signals resolution to the resolution of the TVs screen. Therefore if you have an HD Ready TV (1280x720 pixels) or a Full HD 1080P TV (1920x1080 pixels) and you watch Freeview or a DVD that has a resolution of 768x576 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 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.
All LCD and Plasma televisions have an upscaler to accommodate the different resolutions of various sources so that they fill the native resolution of the screen. What is different about a Near HD televisions is that they use a much more powerful processor in the upscaler that allows them to do a much better job than other televisions.
Whilst advanced software algorithms are able to estimate what the extra pixels should display in the upscaled picture it isnt able to turn a Standard Definition image in to a genuine High Definition picture.
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 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.
Should you buy Near HD TVs and DVD Players?
Obviously an upscaled SD 576 line picture is not as good as a 1080P Full HD picture no matter how much digital processing is done. Nonetheless there is no doubt that a much better upscaler in a television produces a noticeable improvement in the picture quality so that it is closer to 1080P picture. A Near HD TV makes even more sense if you arent willing to pay a monthly charge for HD from Sky, Virgin Medias Cable, Tiscalis Service or Blu-Ray discs. Even if you opt for Freesat there is a limited amount of HD channels available so your choice of programmes is limited. Because HD isnt freely available, especially with out paying for it, a Near HD TV is worth considering that will produce an improved picture with virtually any content including 480i, 576i, 720p as well as DVD, Standard Definition Broadcasts and computer games. With all of these sources the picture 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. - 32388
About the Author:
Armadeus Cornelius is an AV enthusiast and expert with nearly 2 decades 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 upconvert dvd player and toshiba flat screen 37
