Consumers have high expectations of the video quality from today’s HDTVs. Unfortunately, they are often disappointed in the viewing experience they receive, a feeling that is compounded by the price tag on these displays. There are a number of reasons for this, ranging from interlaced-to-progressive conversion to the increased compression in digital signals, all of which lead to artifacts in the video.
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Today’s LCD and plasma HDTVs have millions of pixels on the screen that are each electronically addressed and given a color value. This produces a very high, precise resolution that makes every video error quite noticeable. Furthermore, to meet consumer demand, displays are available in much larger sizes. Whether it’s a 30- or 70-inch screen, artifacts becomes much more apparent as the image is made larger.
As a result, video-processing technologies are essential in order to achieve outstanding picture quality for today’s high-resolution video displays. When buying a video processor, consumers should look for the following technologies and features to eliminate these artifacts and receive the best-possible viewing experience from their HDTVs.
In order to achieve the outstanding picture quality viewers expect, incoming video signals need to be properly scaled to match the pixel resolution of displays. 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, 1920×1080. A quality video processor will scale images horizontally and vertically, as well as provide up-conversion from 480p, 576p, 720p, and 1080i to any output resolution from VGA (640×480) to 1080p (1920×1080), without ringing or other artifacts found in solutions where scaling engines are integrated into an MPEG decoder chip. In addition, a comprehensive processor is capable of supplying high-resolution images directly to the display using its HDMI output, completely bypassing the display’s internal processing chip.
LCD and plasmas use progressive technology to display images instead of interlaced technology. For these displays, an interlaced signal needs to be deinterlaced to be progressively displayed, a conversion process that can result in jaggies, combing, and other degrading effects. As the errors will be more noticeable on larger screens, motion-adaptive deinterlacing and edge-adaptive processing for video sources are necessary to eliminate these artifacts.
3. Progressive Reprocessing
General purpose chips in DVD players, AV receivers, and set-top boxes do not provide proper deinterlacing. To improve these signals to optimize images on high-resolution displays, Progressive Reprocessing (PReP™), an Anchor Bay video-processing technology, 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 jaggies, combing, and other degrading effects. PReP technology allows 480p, 576p, 1080p/50, 1080p/60, and other formats to be processed by this method.
4. Lip Sync
Lip sync is a problem often present in AV sources where the audio signal does not match up with the video signal, such as when a character’s words are heard before their lips move. This can be corrected by video-processing technologies that automatically delay the audio signal.
5. Chroma Artifacts
Incorrect up-sampling of the chroma (color) signals by MPEG decoders in DVD players and satellite receivers causes artifacts such as horizontal streaks in images with highly saturated colors. With a high-end video processor, chroma artifacts are automatically detected and removed, resulting in a significantly improved picture quality with much clearer and true-to-life images.
6. Input Aspect Ratio Conversion
Complete input aspect ratio conversion allows viewers to watch content of various aspect ratios the way they want, with independent vertical horizontal zoom and pan controls.
7. Output Controls
Extensive output controls allow any display to be driven at its optimal resolution, ensuring peak performance. All analog and digital signals from all video sources can be connected to the display with one digital connection. Some video processors offer preset output resolutions that work with all popular HD displays all the way up to 1080p.
8. Frame Rates
Movies are typically shot on film that has 24 frames per second. When this film is played back at 60 Hz, the smooth pans seen in the cinema have motion judder. Many new displays can accept frame rates that are multiples of film’s frame rate (24/48/72 Hz). Video processors can output a film-based source at these rates, bringing the home theater experience as close to the cinema experience as possible.
9. Overscan and Underscan
Many displays inherently have overscan, which means that some of the available image is actually not on the screen. Overscan and underscan controls in video processors ensure that all of the viewer’s sources are displayed correctly on their screen.
10. Individual Picture Controls
Individual picture controls on each input, including brightness, contrast, saturation, hue, and sharpness, with separate memory banks for each input resolution, can help achieve peak performance when sources such as HD set-top boxes output different resolutions for SD and HD programming.
All of these technologies are important in obtaining the best-possible picture on any HDTV, but it is difficult to find a video processing system that offers such a complete solution. For consumers, the DVDOÂ® iScan™ VP50, a high-definition video processor, offers all of the processing power of Anchor Bay’s Video Reference Series™ (VRS™) technologies in one complete system. Working as a hub, it brings all of your home-theater gear under the control of one compact unit.
Learn more about the DVDOÂ® iScan™ VP50 at www.dvdo.com