Throughout most of its history, viewers have watched television on relatively small CRT screens that used interlaced scanning technology to display standard-definition content. In the past several years, however, an exciting digital revolution has taken place in television that has transformed â€œwatching TVâ€ into a real experience. The CRTs of old have given way to large, flat-screen LCD and plasma displays that now use progressive scan technology to display high-definition images. For viewers, the result is a highly detailed television experience on a much larger viewing area. But as with any dramatic change, there are bound to be a few bumps in the road. For television, these bumps are video artifacts, or video errors, and they require several different video processing technologies for viewers to achieve the best-possible viewing experience.
From CRT to Flat Screen Displays
When CRTs were the norm, video processing at the display level wasn’t a big concern. The reason for this is that the technology used to display images on CRTs isn’t very precise, resulting in images that are a bit soft and out of focus, which essentially hides artifacts. In contrast, flat-screen displays have millions of pixels on the screen that are each electronically addressed. This produces a very high, precise resolution that creates a realistic viewing experience, but it is also quite revealing to any noise or artifacts.
Furthermore, CRT displays are typically small, ranging in dimensions from 12 to 36 inches. Flat-screens, however, can range in size from a few centimeters across to a wall-filling 103 inches. So noise and other video flaws are literally being amplified on a larger screen. This combination of a precise resolution on a large screen requires video processing technologies such as noise reduction and edge enhancement to achieve a clear, detailed picture.
Edge enhancement technologies isolate areas of the image where hard edges are prevalent and increase fine details without adding halos or ringing. The net effect is quite extraordinary – images have more “pop” and fine detail, such as blades of grass or even the pores on an actor’s face, making the large-screen experience more â€œrealâ€ and even more enjoyable. Noise reduction technologies can remove objectionable ringing and noise in the image before edge enhancement to draw out the fine details in the image.
From Interlaced to Progressive
LCDs and plasmas both use progressive scan technology to display images; however, most signals from broadcasters are in standard-definition, interlaced scan format. An interlaced video signal is captured and sent in two alternate fields. The first field drawn on the screen is all the odd lines. This is followed by the second field, made up of the even lines. In a progressive signal, on the other hand, all the lines of each frame are drawn in sequence.
For these displays, interlaced signals need to be deinterlaced to be progressively displayed, a conversion process that can result in jaggies, combing, and other degrading video effects. For the best image, an advanced deinterlacing technology will feature five-field motion-adaptive deinterlacing and edge-adaptive processing, which uses an adaptive, continuous-angle detection algorithm to accurately identify and smooth image edges.
From Standard Definition to High Definition
With the emergence of HDTV, there is often a mismatch between the signal received and the aspect ratio and native resolution of a display. A display’s aspect ratio is essentially the shape of the screen. Two common aspect ratios are 4:3 (universal for standard definition) and 16:9 (universal for high definition). Depending on the display, the 16:9 signal might have to be displayed on a television with a 4:3 aspect ratio, and vice versa. This can lead to image loss, particularly on the sides, and requires aspect ratio conversion for a complete picture.
Video processing solutions that offer full aspect ratio control provide support for multiple input aspect ratios and multiple display aspect ratios, allowing viewers to watch content the way they want. These solutions also need to support other image manipulation features such as zoom, border control, and panamoramic stretch mode to support 4:3 content on a 16:9 display.
The native resolution of a display is how many physical pixels make up each row and column of the visible area on the display’s surface. To get a proper match from the signal to the display, scaling is required. Most commonly, video scalers “upscale” or “upconvert,” taking low-resolution (standard definition) video and increasing the resolution to high-resolution (high definition) video. In the case of a 1080p display, all input signals (except those from a 1080p source, like Bluray or HD-DVD) must be upconverted from their lower resolution to the resolution of the display.
A One-Component Solution
As we’ve seen, several types of video processing technologies are needed to get the full benefit of the digital television revolution. But that doesn’t mean you need several different components to obtain these technologies. For consumers, Anchor Bay’s DVDO iScan VP50PRO high-definition video processor offers the company’s complete suite of Video Reference Series â„¢ (VRSâ„¢) technologies to meet all of these video processing needs, and more, all in one single component.
The VP50PRO features VRS Precision Detail & Edge Enhancement and VRS Precision Noise Reduction for clear, detailed images on large-screen HDTVs. Anchor Bay’s 10-bit Precision Video Scaling IIâ„¢ can independently scale an image horizontally and vertically, up to 1080p, to achieve outstanding picture quality for today’s high-resolution/high-definition displays, while offering full aspect ratio control.
VRS Precision Deinterlacingâ„¢ eliminates many of the artifacts found in common deinterlacers to produce a smooth image, free of artifacts such as jagged edges and combing. All processing is performed at full 10-bit resolution to preserve all the detail and subtle nuances in the video source.
Additionally, to overcome the poor interlaced-to-progressive conversion by general purpose chips in DVD players, AV receivers, and set-top boxes, the VP50PRO features Progressive Re-Processing (PRePâ„¢), an advanced video processing technology that reverts the progressive video signal output from source equipment to its original interlaced format. PReP then converts the interlaced signal to progressive format, this time applying the source, edge, and motion adaptive algorithms in its Precision Deinterlacing technology to eliminate degrading effects. PRePâ„¢ is a technology exclusive to Anchor Bay.
Working as a hub, the VP50PRO brings all analog and digital home-theater gear under the control of one slim unit that compliments the sleek look of today’s components and displays. Additionally the VP50PRO has individual controls for all connected sources so that the everything can be optimized and then sent over a single connection to the display.Day and Night viewing modes canalso be set up so that the viewing experience is not ruined by a washed out or overlydark picture.
For more information about the DVDO iScan VP50PRO and other products available from Anchor Bay please visit: www.anchorbaytech.com