January 14, 2008
| by EH Staff
Video processors are, in essence, the unsung heroes of our home theaters. They aren’t touted or explained much beyond some spiffy-sounding name in a spec sheet. And most people have no idea what they actually do. But they are essential to enjoying video today.
Video processing has a lot to do with the quality of an image displayed on a TV or video display. Video processors are found in TVs, DVD players, audio/video receivers, computer displays and external video processors. The reason video processors are so important is that there are so many different formats and resolutions of video available today, and your DVD player, TV and audio/video receiver need to be in sync with what the video is, where it’s coming from, where it’s going and what it needs to be in the end.
What They Do
One of the biggest tasks of a TV’s video processor is to convert an incoming video signal, say that of a 1080i-resolution HDTV show, to the TV’s native 720p resolution, or vice versa. A higher-resolution “Full HD” 1080p set will “upconvert” the lower-resolution 720p and 1080i signals to its higher resolution.
Video processing is a beautiful thing when it works well, and it’s a disappointment when it does not. And that’s the problem, because many TV sets have inexpensive (read: cheap) video processors that aren’t very good at what they do. Joel Silver, founder and president of video calibration expert Imaging Science Foundation (ISF) estimates that you need to pay about $3,500 for a TV that contains a really good video processor. Keep that in mind when you’re drooling over an LCD with a $1,000 price tag.
Some functions of a video processor include:
- Scaler. This will upconvert or downconvert a video’s resolution to the TV’s own (or native) one. Image distortion such as soft or blurred edges and text that is difficult to read can result.
- Deinterlacer. A deinterlacer takes an interlaced picture (1080i) and converts it to a progressively scanned image, like 720p. Artifacts such as jagged edges on objects can result.
- 3:2 pulldown. This feature converts the 24 frames per second of film that are stored on DVDs to the 30 frames per second displayed by today’s video by adding frames in a 3:2 pattern. This processing has become much better in recent years but can still cause a “judder” effect on horizontal pans.
- HD inverse telecine. This is a faster, more expensive 3:2 pulldown that is important for 1080p sets, but that is often unavailable. Without it, resolution can be cut in half. If you’re getting a 1080p set, look for a processor with this feature.
When do you need an external video processor? When you want a better picture on an HDTV display, say the experts. Some external processors will also eliminate artifacts, like “mosquito noise” that results from video compression and other problems.
“Because external solutions are available, one important feature [in a TV] is being able to bypass all internal video processing so that you can take advantage of any available external solution without being hindered by the internal processing,” says Josh Allen, product marketing manager at video processing company Anchor Bay.
Down the Road
Afraid you’ll buy an HDTV and need to upgrade it in two years? Don’t worry about having to replace the whole thing for new technology. Just buy a better DVD player with a good processor. Upconverting DVD players, like those that play high-def DVD formats Blu-ray Disc and HD DVD, will upconvert standard 480-line DVD images to stunning 1080p. It’s a good, inexpensive way to get good video processing. Buying a new audio/video receiver with a good processor in it will help as well. Though it’s best to start by getting a 1080p set now.