Specifications

high contrast transitions in the video, which are either an MPEG-2 artifact or an intentional attempt to
sharpen the image artificially (or sometimes both). I continue to maintain that edge halos are the
single greatest impediment to a film-like presentation at home, so I wanted to avoid any player that
worsened or caused halos in hardware. If you're curious, I'll try to explain the problem as succinctly as
I can (for everyone else, feel free to jump to the next paragraph). Unique problems occur at the points
of entry and exit in all sampled systems - digital video systems among them. The input analog-to-
digital converter must avoid data frequency content higher than half the sampling rate; if present, such
data will “fold over” and cause nasty-looking distortions. This phenomenon is called aliasing. Similarly,
there are residual high frequency sample rate contaminants at the digital-to-analog converted outputs
of digital systems. Filters are applied at such inputs and outputs to remove offending signal content.
Input filters are found on the professional equipment used to create content; that's out of our control
but they tend to be very high quality, so it's not a concern. But the way video output filters are
implemented in consumer-grade DVD players can cause a damped oscillation or ringing in the video.
Onscreen, video ringing looks just like edge halos. An initial half cycle of overshoot will appear as a
bright halo around a dark object. An additional half cycle of rebound undershoot will put a dark halo
around the first bright halo, and so on. So for my next in-store test, I navigated to one of AVIA's 50
IRE test patterns, found at Gray Scale & Levels / Black and White Levels / Black Bars + Half Gray, and
looked at the video transition on the ‘scope. (I had confirmed previously that there is no ringing on the
disc by performing a screen capture on my computer and magnifying the image.) Sure enough, on the
‘scope's screen, ringing revealed. For each player, I noted the number of half-cycles, and their
amplitudes and widths. After I had finished all my measurements, I looked at my data and factored in
published measurements; my initial leading candidate had been eliminated. This was a great
disappointment, since the price of that player was reasonable. (I also had hoped that the winning
player would have the Sage/Faroudja chip set; that was not to be, but Silicon Image does a fine job as
well.) The player that came out on top was the obnoxiously expensive Denon DVD-9000. Sigh.
Okay, at this point you're probably asking yourself what does this have to do with me? I wouldn't
expect you to buy an oscilloscope and to duplicate my nonsense when you find yourself in the market
for a new player, so here's what I'd suggest. Before you begin, read test reports that contain hard
data; put together a short list of leading candidates that have the best performance for your target
budget. If you don't already have the AVIA Guide to Home Theater DVD, pick one up; you should own
one to set up your display properly anyway. When you visit brick & mortar shops to assess players,
make sure they're connected to a fine CRT-based, HDTV rear projector's 480p (progressive)
component video inputs, and make sure that each player is in the progressive mode. (Even if you
currently don't have a display that can accept progressive video, trust me, you eventually will. Plan on
buying a progressive player.) Make sure that the display's scan velocity modulation (SVM) is disabled
and that the sharpness is at the nominal setting. SVM may be considered another form of artificial
image sharpening and it, too, adds halos to the image. If the display doesn't offer the option of turning
SVM off, ask to see the player on a display that can disable SVM. (And if possible, you should consider
turning SVM off at home.) Check AVIA's widescreen enhanced resolution pattern; every frequency
(they are labeled and appear as increasingly tighter spaced vertical bars within circles) should be clear,
particularly within the 6.75 MHz circle. Take a look at both the sharpness test pattern, found at
Resolution / Sharpness, and the Black Bars + Half Gray test pattern. Observe the halos. Notice widths
and subjective halo brightness. Then display the main menu from Toy Story and look for banding (see
the Chroma Upsampling Error article). Seriously consider purchasing the player that has a flat and
extended frequency response, no chroma upsampling error, and rings the least. That's the player that
should come closest to providing a film-like presentation.
The Transcoder
So I bring my new treasure home and eagerly connect the DVD player to my system. I can now bypass
the Faroudja and connect the component video outputs from the Denon directly to the Extron CVC200
component-to-RGB-HV converter (transcoder). I pop the AVIA disc into the player for a quick
performance check and, as I navigate, I'm immediately struck with the speed of the player's drive. It
snaps from screen to screen; layer transitions should be virtually invisible, an added bonus. All the test
patterns look fine, so I replace the AVIA disc with arguably the best-looking DVD to date, and certainly
the best-looking of 2002, Star Wars Episode II: Attack of the Clones. I jump to a chapter at random
and sit back, smiling in anticipation. Uh, oh. What's that? The contrast is changing, cycling up and
down every twenty seconds. Twenty seconds? Damn! It's the cursed Macrovision! I quickly replace
AOTC with Harry Potter and the Sorcerer's Stone, famously free of Macrovision. A lovely stable picture,
wonderfully detailed.
Is the problem in my projector? The new player? Is it the transcoder? Out comes the oscilloscope. I
connect the Y-output from the Denon to the ‘scope's channel A and examine the R, G, and B outputs of
the Extron on the ‘scope's channel B. There they are, the Macrovision pulses from the Denon's Y-
output, obscenely thrusting up and down. And on Extron's R, G, & B outputs, the video gain rises and
falls synchronous with Macrovision. Damn! A quick bit of web research revealed that Macrovision has
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DVDFILE.COM: Mr. Blandings Builds his Dream Theater
4/7/2003
http://www.dvdfile.com/news/special_report/tech/mrblandings/upgrades.html