Progressive-scan DVD Players Deliver Picture-quality Benefits That Live Up to the Name
If you're in the market for a DVD player, it's hard to miss the fact that the higher-priced models all prominently sport a mysterious feature known as progressive-scan video output. You may have seen the feature credited with providing a smoother, more realistic (or "film-like") picture. It's all true, but you needn't take our word for it. To understand why a progressive-scan DVD player is worth the additional investment, read on...

First Things First
The first thing to understand about progressive-scan technology is that it won't do you any good unless you have a digital TV, or a monitor capable of at least SDTV resolution (which includes HDTV and EDTV monitors). Without digital TV's high-speed scanning abilities to back it up, a progressive-scan DVD player can't achieve the picture-quality advantages it was designed to deliver. We'll explain all this in more detail below. The good news is that one day soon all of us will own digitally compatible TVs — and in the meantime, any progressive-scan DVD player will function every bit as well as any of its lesser brethren with your analog TV. But don't go plugging an expensive progressive-scan player into your 1980s-vintage boob tube and expect to see a spectacular improvement over the closeout DVD player you bought on clearance last year. You'll be disappointed.

Why do I Need a Digital TV?
Televisions generate their pictures by rapidly drawing a succession of horizontal lines across the screen with an electron beam, exciting the phosphorescent screen coating to create patterns of light on the surface. This is called scanning, and each of the lines drawn by the electron beam is known as a scan line. On a traditional analog TV, there are 525 scan lines that comprise the image, 480 of which are actually visible onscreen. The DVD format also uses 480 visible lines to construct a picture. So what's the problem?

Speed Fills
Analog TV fills the screen by executing two alternating passes of the electron beam: The first pass hits the odd lines in the sequence (1-479) and the second fills in the even lines (2-480). Each of these two groups of lines is known as a field, and the combination of two fields (encompassing all visible scan lines) is known as a frame. An analog TV draws one field every 1/60th of a second, completing a full frame 30 times per second. Because the two fields are interlaced to form a frame, this is called an interlaced scan.

Digital TV's advantage lies in the speed at which it is capable of drawing these scan lines. Rather than building a frame from two interlaced fields, a digital display can complete a progressive scan of all 480 lines (in sequence from 1-480) every 1/60th of a second — the same amount of time an interlaced display takes to fill just half the screen. The result is a visibly fuller, sharper picture, with virtually none of the striping visible on a conventional TV. The picture is also noticeably brighter, since twice as much screen area is illuminated by the electron beam in the same period of time. These characteristics are particularly important as the size of the display increases — a progressive-scan picture looks much more solid and real when blown up to super size on today's mega projection screens.

Furthermore, the characteristic "flicker" associated with interlaced scanning (particularly problematic when the image contains fine horizontal details that are present in only one of the two interlaced fields) is noticeably reduced with progressive scanning, making it easier on your eyes. Less eye fatigue means more distraction-free enjoyment from your DVD movies.

Be Moved Without Losing Your Edge
With moving images, the advantages of progressive scan are even more pronounced. When tracking fast-moving images across the screen, interlaced displays are plagued by significant distortions known as motion artifacts. This is because most true video sources actually generate 60, not 30, unique images per second. Interlaced displays represent each of these 60 unique stills, but each uses only half the screen's available scan lines. When an image moves quickly across the screen, the difference in its position from one field to the next becomes apparent, and the interlacing visually combines disparate fields, creating an effect known as "feathering" or "combing." Image definition becomes blurry and indistinct when movement occurs, but clarity is restored once the image becomes stationary again.

By contrast, since a progressive-scan display is capable of reproducing an entire frame for each unique still in the video stream, it can render moving objects with much greater clarity. Each frame appears cohesive, with no trace of the artifacts that make the interlaced display appear to lose focus when objects move.

Sounds Kinda Familiar...
If you've spent any time examining the features of digital TVs, you probably know that most models nowadays include some form of de-interlacer (also known variously as a progressive-scan upconverter, interlaced-to-progressive [I/P] converter or line doubler). The purpose of such circuits is to "convert" incoming interlaced signals (like analog TV broadcasts) to a progressive-scan format, using advanced interpolation algorithms to intelligently estimate the content of the missing lines from each interlaced field.

These circuits are great for improving the picture quality of interlaced broadcast signals — and yes, they can work to improve the picture quality of a DVD player that can't generate its own progressive-scan output. However, a progressive-scan player will provide superior results, for two important reasons.

First, since the de-interlacing circuit in a TV is designed to work with multiple different types of input signals, it is not optimized to capture the precise detail present in the DVD format. Secondly, a progressive-scan DVD player's integrated de-interlacing circuitry processes the signal in the digital domain. Because it skips several digital-to-analog and analog-to-digital conversion steps that are necessary before processing can take place in the TV, it provides a cleaner signal path with less degradation for a more faithful progressive-scan representation of the image.

Progressive-scan DVD Players Deliver Picture-quality Benefits That Live Up to the Name
If you're in the market for a DVD player, it's hard to miss the fact that the higher-priced models all prominently sport a mysterious feature known as progressive-scan video output. You may have seen the feature credited with providing a smoother, more realistic (or "film-like") picture. It's all true, but you needn't take our word for it. To understand why a progressive-scan DVD player is worth the additional investment, read on...

First Things First
The first thing to understand about progressive-scan technology is that it won't do you any good unless you have a digital TV, or a monitor capable of at least SDTV resolution (which includes HDTV and EDTV monitors). Without digital TV's high-speed scanning abilities to back it up, a progressive-scan DVD player can't achieve the picture-quality advantages it was designed to deliver. We'll explain all this in more detail below. The good news is that one day soon all of us will own digitally compatible TVs — and in the meantime, any progressive-scan DVD player will function every bit as well as any of its lesser brethren with your analog TV. But don't go plugging an expensive progressive-scan player into your 1980s-vintage boob tube and expect to see a spectacular improvement over the closeout DVD player you bought on clearance last year. You'll be disappointed.

Why do I Need a Digital TV?
Televisions generate their pictures by rapidly drawing a succession of horizontal lines across the screen with an electron beam, exciting the phosphorescent screen coating to create patterns of light on the surface. This is called scanning, and each of the lines drawn by the electron beam is known as a scan line. On a traditional analog TV, there are 525 scan lines that comprise the image, 480 of which are actually visible onscreen. The DVD format also uses 480 visible lines to construct a picture. So what's the problem?

Speed Fills
Analog TV fills the screen by executing two alternating passes of the electron beam: The first pass hits the odd lines in the sequence (1-479) and the second fills in the even lines (2-480). Each of these two groups of lines is known as a field, and the combination of two fields (encompassing all visible scan lines) is known as a frame. An analog TV draws one field every 1/60th of a second, completing a full frame 30 times per second. Because the two fields are interlaced to form a frame, this is called an interlaced scan.

Digital TV's advantage lies in the speed at which it is capable of drawing these scan lines. Rather than building a frame from two interlaced fields, a digital display can complete a progressive scan of all 480 lines (in sequence from 1-480) every 1/60th of a second — the same amount of time an interlaced display takes to fill just half the screen. The result is a visibly fuller, sharper picture, with virtually none of the striping visible on a conventional TV. The picture is also noticeably brighter, since twice as much screen area is illuminated by the electron beam in the same period of time. These characteristics are particularly important as the size of the display increases — a progressive-scan picture looks much more solid and real when blown up to super size on today's mega projection screens.

Furthermore, the characteristic "flicker" associated with interlaced scanning (particularly problematic when the image contains fine horizontal details that are present in only one of the two interlaced fields) is noticeably reduced with progressive scanning, making it easier on your eyes. Less eye fatigue means more distraction-free enjoyment from your DVD movies.

Be Moved Without Losing Your Edge
With moving images, the advantages of progressive scan are even more pronounced. When tracking fast-moving images across the screen, interlaced displays are plagued by significant distortions known as motion artifacts. This is because most true video sources actually generate 60, not 30, unique images per second. Interlaced displays represent each of these 60 unique stills, but each uses only half the screen's available scan lines. When an image moves quickly across the screen, the difference in its position from one field to the next becomes apparent, and the interlacing visually combines disparate fields, creating an effect known as "feathering" or "combing." Image definition becomes blurry and indistinct when movement occurs, but clarity is restored once the image becomes stationary again.

By contrast, since a progressive-scan display is capable of reproducing an entire frame for each unique still in the video stream, it can render moving objects with much greater clarity. Each frame appears cohesive, with no trace of the artifacts that make the interlaced display appear to lose focus when objects move.

Sounds Kinda Familiar...
If you've spent any time examining the features of digital TVs, you probably know that most models nowadays include some form of de-interlacer (also known variously as a progressive-scan upconverter, interlaced-to-progressive [I/P] converter or line doubler). The purpose of such circuits is to "convert" incoming interlaced signals (like analog TV broadcasts) to a progressive-scan format, using advanced interpolation algorithms to intelligently estimate the content of the missing lines from each interlaced field.

These circuits are great for improving the picture quality of interlaced broadcast signals — and yes, they can work to improve the picture quality of a DVD player that can't generate its own progressive-scan output. However, a progressive-scan player will provide superior results, for two important reasons.

First, since the de-interlacing circuit in a TV is designed to work with multiple different types of input signals, it is not optimized to capture the precise detail present in the DVD format. Secondly, a progressive-scan DVD player's integrated de-interlacing circuitry processes the signal in the digital domain. Because it skips several digital-to-analog and analog-to-digital conversion steps that are necessary before processing can take place in the TV, it provides a cleaner signal path with less degradation for a more faithful progressive-scan representation of the image.