Near HD Televisions

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.

Why do you need a near High Definition Television?

There has never been so much choice of HD programmes and movies. Both Sky and the BBCs and ITVs Freesat provide multiple channels of HD. Alternatives to these are Blu-Ray, HD downloads on the Web, or On Demand services from Virgin Media or Tiscali. It might appear as if there is a lot of choice but it still isnt possible to watch all channels in HD. If you arent prepared to pay a monthly subscription fee then Sky isnt an option and your choice will be narrowed considerably because they have the most choice of channels. Furthermore if you dont want to buy or hire Blu-Ray Discs the choice is even more limited leaving 2 channels of free HD channels on Freesat or a small amount of On Demand programmes or films from Tiscali or Virgin Media. Because of these limitations on available HD programmes the television manufacturers believe that there is a need for Near High Definition television.

What is Standard Definition?

The picture of a PAL television consists of thousands of pixels. On a standard definition television the picture is made up of horizontal lines that are made up of 768 pixels and there are 576 horizontal lines i.e.768 pixels 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.

High Definition broadcasts in the United Kingdom are at 720P (1280×720 pixels) or 1080i (1920×1080 pixels). If you want to experience HD TV programmes you will need a TV set that is at least HD Ready with a resolution of 720P (1280×720 pixels). There are also higher resolution televisions than HD Ready TVs known as Full HD Ready 1080P (1920×1080 pixels) but there are not any 1080P broadcasts available at present. To benefit from this increased resolution you will have to rely on Blu Ray discs or HD down loads from the web.

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.

Near High Definition TVs are produce a near High Definition image from a Standard Definition source using a method called 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 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.

How well a television upscales an image will depend on the quality of the incoming signal and the quality of the processing chip. Different televisions have different abilities to upscale a picture. The quality of the upscaled image that is displayed will also depend on the quality of the TV sets electronic components and the screen.

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.

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 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.

Toshibas upscaling DVD player is the XDE model which isnt the same as other DVD upscalers that are available because it deinterlaces the picture and then upscales the Standard Definition 576 lines to a 1080p near HD resolution. As with the Resolution + on the Toshiba ZV range of Televisions the picture is enhanced to give more detail, more vivid colours, and improved contrast using the same techniques as detailed above.

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.

Also if you buy a near HD television and at some time in the future more free content becomes available, or you decide you are prepared to pay a monthly subscription for HD, then you wont need to upgrade your TV because it will already be a Full HD 1080p television. The only near HD products that are available in the UK are manufactured by Toshiba with their ZV range of televisions and the XDE DVD player but more manufacturers will have similar products shortly.

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’ televisions and a large selection of AV products at low prices. For your convenience you may also find these links useful hd dvd upconversion and toshiba regza 52