Wednesday, January 7, 2009

Magnavox 19MF337B 19-Inch LCD HDTV

With its ultra sharp widescreen HD picture, rich color, HD media connectivity, Dolby Digital sound, SPDIF audio output, integrated digital tuner and multiple input options, the 19MF337B is a superb TV and a great PC monitor.
Customer Review: Bought less than a year ago and now will not turn on
Our TV just gave out after owning it for less than a year. The power button is lit red but wil not advance. The TV will not go beyond a black screen. I called customer service to be told, for a fee of $274.62 plus tax they will replace it. I can buy the same tv on the web for the $240 range! Not good customer care or product.
Customer Review: less than 9 months, picture tube going.....
I bought this set dec 10. in the last 2 months we've noticed horizontal lines and shadows. I've checked everything according to cable lines. It is the TV set. The service center admitted that this set does have a picture tube problem. they can fix it for $274.00. I bought it originaly for about that price. I'm really angry that it is dying so soon. All other TV's I've ever owned have lasted for many many years! I really liked this set up till this problem. In my opionion, less than one year for your money is not worth it!


In the UK, the picture signal is known as PAL and is used for SD (standard definition) pictures - these are usually associated with DVD and broadcast TV. This has a resolution of 720x576 (720 pixels across, and 576). A pixel makes up a single "dot" shown on the screen and together these dots make up the entire picture. You can't buy a plasma or LCD screen with this resolution however. The screens resolution is usually a lot higher than this and is referred to as the native resolution.

This means that every screen must process the picture and scale it to meet the native one. The accuracy of the scaling here is very very important to the image quality. A very important question regarding HD televisions was whether the image was linear to the native resolution. That is - would the horizontal and vertical proportions be the same. If it wasn't linear the screen would create artefacts that would result in a worse image.

To highlight this, see the example below. If you have 3x42 inch screens with the following resolutions but lets assume identical otherwise:

screen1: 1280x720

screen2: 1024x768

screen3: 852x480

If we try and feed this televisions an HD signal which is outputted at a resolution of 1280x720 (720p) we can see the following.

Screen 1 is able to display the picture at 1:1 - that is each pixel of the HD signal can represented equally as each pixel on the screen.

Screen 2 would have to scale the image 80% horizontally (1024/1280) and 106% vertically (768/720). This means that each axis is going to have different proportions and this will cause artefacts on the screen.

Screen 3 would have to scale the image 66% on both the horizontal and vertical axis (852/1280 and 480/720). Although not quite as good as

screen 1, as this is linear the Television can scale this with quite simple maths.

To summaries, Screen 1 would produce the best picture as no scaling is involved.

Screen 3, although it has the lowest resolution will display the picture well as it is linear.

Screen 2 would display the WORST picture, despite having a higher resolution to screen 3.

Bear in mind that these are moving images and not still pictures - the more artefacts on the screen, the more it notices.

Higher resolution screens will be more expensive due to the faster and more advanced processing needed to map an image to match the native resolution of the screen. This will be true for any pixel based display - think computer monitors. The pioneer and Panasonic entry level screens are very good examples of SD screens that outperform most of the HD televisions around.

The consumer desire for bigger pictures means we need higher quality broadcasts, and is part of the reason for the birth of HD televisions. However, it isn't just the resolution that will depend on the picture quality. A high resolution set with poor image processing will be worse than a set with lower res/better processing. If you are looking at a sales brochure, your friend claims resolution is the deciding factor, or a salesman tries to talk over you, don't be fooled by the lingo and refer back to this article.

The author is an expert on HD Televisions and equipment. For more information like this, visit the website http://www.hd-televisions.co.uk

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