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Editor's HDTV Pick

HP 47 inch MediaSmart 1080p LCD HDTV "Out of the box" digital media platform. Enjoy videos, pictures and music from home network + digital media delivered over your broadband Internet connection + 3 x HDMI

Movies for the cinema shot on 35mm or 70mm film capture 24 individual images (frames) per second which are projected at 48 frames per second to reduce flicker. To achieve 48 frames per second each frame is projected twice.

Television broadcast systems are field based. For example, NTSC (National Television Standards Committee) Video is interlaced with each frame being constructed from two consecutive fields of video containing 50% of the 480 horizontal scan lines containing picture information. NTSC video displays at 29.97 frames or 59.94 fields per second.
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ATSC

An ATSC tuner (also referred to as an ATSC receiver) allows reception and decoding of ATSC digital television (DTV) signals broadcast over the air by television stations. ATSC tuners perform a number of tasks to fit the television signal received to the particular television display including: (read more..)

In deciding between 1080p (1,920 x 1,080 pixels) Full High Definition (HD) resolution and 720p (1,280 x 720) High Definition (HD) there should be an appreciation that resolution is not the only factor contributing to picture quality. In fact, resolution comes fourth in a recent SMPTE (Society of Motion Pictures and Television Engineers) study which ranked contrast ratio, color saturation, color temperature or greyscale ahead of it in ranking picture aspects the human eye sees in order of importance.

Two factors influence which resolution is more appropriate namely,

Screen size and
Viewing distance.

In general terms, the closer you sit to the on-screen image the more detail you can see as the image fills more of your field of vision. So the closer you are getting to the display/screen the higher the resolution should be getting to maintain picture quality. Moving away from the display/screen reduces the discernible difference between resolutions eg. 1080p vs 720p.
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Video processing is becoming more important for improvement of overall picture quality, especially with larger high definition displays which magnify any image defects. Video processing can optimize contrast levels, adjust color levels, reduce unwanted signal noise and remove image artefacts.

Samsung’s Digital Natural Image (DNle) engine combines a set of four image processors and a six-times density enhancer to deliver an optimized on-screen image. Samsung’s DNIe that can process video signals from any source including high-definition digital broadcasting, DVD, video camera, PC and game consoles.
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Philips VIDI is an enabling lamp technology for both micro and front projection equipment. VIDI is referred to as an enabling technology as it resides in the lamp electronics. It offers increased brightness and enhanced contrast for significant improvement of picture quality for end users.

VIDI electronics turn the light from a projection lamp into a two pulse system; a brilliant pulse and dark pulse. The dark pulse enables enables enhance contrast delivering smoother more vivid pictures. On the other hand, the brilliant pulse boosts projection bulb brightness by up to 25% to 30% putting more lumens of brightness on the projection screen.

Philips expect VIDI technology to allow projector manufacturers to provide consumers with the flexibility to tune their projector for multiple applications eg. data vs. video projection. Philips have worked in close cooperation with Texas Instruments for combining VIDI with TI’s BrilliantColor technology.

BrilliantColor which is a Texas Instruments trademarked technology for delivering improved brightness and a wider range of colors. Traditionally, most display devices render images using a combination of the three primary colors red, green and blue. The full gamut of colors visible to the human eye cannot be reproduced using this approach, with the color space subset covered not including vivid colors such as yellow and cyan commonly seen in nature.

By processing up to six color channels BrilliantColor projector manufacturers to create multi-primary color systems by adding colors such as yellow, cyan and magenta colors for color rendering. As well as increasing the color space which can be rendered with the added color filters the system also utilizes the light source more efficiently with a 50% increase of 50% brightness.

A further benefit of BrilliantColor technology derives from its use of floating point arithmetic for more accurate rendering calculations. According to Texas Instruments, this results in less noise and more accurate colors at the display with over 200 trillion color shades being possible.

For clear action images without motion blurring an LCD display needs a fast response time (minimal latency). Response time is more critical for motion-intensive applications such as gaming. The faster the response time, the faster the screen can be refreshed and the less chance there is of the motion blurring or ghosting that LCD displays are suspect to. The blurring is a result of a display not being able to keep up with the output from the video processor.

Unlike LCD displays, plasma and CRT displays have a virtually instantaneous response time and are not prone to motion blurring.

The two most common measurement methods are “rise-and-fall” and “gray-to-gray”. A technical specification for rise-and-fall is available from VESA (the Video Electronics Standards Association). Rise-and-fall is measured as the time taken for a pixel to change from black to white (rise) and back to black again (fall). Gray-to-gray is the time to change from one shade of gray to another. Transitions between the fine graduations of gray-to-gray can be 3 to 4 times slower than those of rise-and-fall because of the lower driving signal for the transition.

Consumers can easily become misled if they are not aware response times quoted may be for different measurement techniques. As next to all video images displayed contain grayscale images, the gray-to-gray response rate gives a better idea of the real world response rate of a display.

It should be noted that LCD manufacturers are making excellent headway in closing the response time performance gap with plasma and CRT displays with LCD response times being some three times faster than a couple of years ago. An 8 ms or less response time is not hard to find. Faster response times have also given manufacturers the option of utilizing another LCD blurring reduction techniques including a faster frame rate through interpolated frames or inserted black frames.

A response time lowering technology also worth mentioning is Viewsonic’s Amplified Impulse Technology which delivers LCD displays with a 4ms response time. The technique used is the application of a short, higher drive signal to jump-start LCD pixels in their transition.

LED backlighting technology has numerous advantages over the conventional mercury-arc lamps CCFL (cold cathode fluorescent tube). Advantages include:

LCD Blur Reduction

LCD displays have a greater motion blur effect primarily because an LCD pixel remains lit, unlike the CRT phosphor screens which are strobed for a very short time. LCD manufacturers have combated motion blur by increasing the refresh rate to 120Hz. Mitsubishi have called their technology Smooth120Hz, Sony have Motion Flow, Toshiba has ClearFrame, LG – TruMotion Drive and JVC call it Clear Motion Drive II. The televisions video processor creates an interpolated frame between each existing frame to achieve 120Hz and make motion appear smoother for the viewer.
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LCD display technology is inherently prone to motion blur primarily due to LCD pixels remaining lit between frames (referred to as sample-and-hold) unlike the rise and fall of pixel lighting with other display technologies eg. plasma. Another possible cause is a response time which is insufficient for the speed required by the frame rate of the display.

LCD manufacturers have moved to combat motion blur through faster response times and doubling of the refresh rate to 120Hz. Faster frame rates (refresh rate) smooths out motion improving the image sequence the eye perceives. To produce the faster refresh rates the video processor interpolates a frame between each existing frame. The faster frame rate makes motion appear smoother to the viewer. Bravia XBR5 models have Sony’s version of the technology, Motionflow, while Mitsubishi has Smooth120Hz, Toshiba - ClearFrame, LG – TruMotion Drive and JVC call it Clear Motion Drive II.
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Australia’s Information and Communications Technology Research Centre of Excellence (NICTA), has developed low cost, very high speed wireless technology integrated into a single chip. The integrated transceiver is extremely small, making it simple to embed into devices. Five (5) gigabits per second wireless transfer of audio and video files will be possible - ten (10) times the current maximum wireless transfer rate. While transfer speed has increased, cost has dropped to 10% of current costs. These are numbers which will transform home entertainment systems to wireless networks.

Consider the scenario posed by NICTA Chief Technology Officer, Embedded Systems, Dr Chris Nicol , “For example, consumers will be able to download a high definition DVD onto their personal digital assistants at a public kiosk in seconds, take it home and play it directly onto their high definition TV.” The range of the new wireless technology is 10m – a suitable distance for home entertainment systems.
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