OTHER TECH

OVERSCAN BLU(ES)

Q. My HDTV has a native resolution of 1,920 x 1,080 pixels and its overscan is about 2.5%. Does that mean that I'm losing 2.5% of the image area that I should be seeing? Also, my set has no pixel-for-pixel display mode, so if a Blu-ray Disc player sends it a 1,920 x 1,080-pixel signal and the TV only displays 97.5% of those pixels, how does it fill out the rest of the screen area? SCOTT MESSBARGER / WESTERVILLE, OHIO

A. If your TV's overscan (the amount of picture area cut off at the edges of the screen) is fixed at 2.5%, then, yes, you'll be missing 2.5% of the original image. But this can be a good thing or a bad thing, depending on the source. TV programs on standard-def channels often have "picture noise," which is actually time code (a frame marker used for editing purposes) and other ancillary data such as closed-captioning information embedded in the first 21 scan lines at the top of the signal.

You don't want to see that noise, of course - which is why all TVs have the ability to make it disappear by overscanning the picture (depending on the set, the amount can range from 2 to 10%). But with digital high-def TV shows and Blu-ray Discs, there are no ragged-looking edges that need to be masked because the full image area is used for picture information. That's why many new HDTVs provide a display mode that lets you view the original image with no overscan. It's frequently called Pixel for Pixel, but is also known as Dot by Dot or Full Pixel.

Such modes offer two key benefits: You get to see the movie as the filmmakers intended, with no cropped picture edges, and the TV can display 1080i and 1080p programs using the screen's full resolution by matching the incoming HD image pixel-for-pixel. But to answer your second question: TVs lacking a zero-overscan display mode must first upscale the image (a process where new pixels are derived by interpolating the data from existing ones) to fill in pixels eliminated by the set's overscan function - a step that results in reduced picture resolution.

HDMI LIES?

Q. What brand of HDMI cables do you use for your Test Reports? Are Monster Cable HDMI cables the best? I've been told that they're not the best. HELP! EDDIE PULOS / VIA EMAIL

A. We use a variety of HDMI cable brands- even some off-brand cables from companies you've probably never heard of! That's because there's no "best" brand; there are only cables that meet the specifications laid out by HDMI Licensing, the organization charged with developing the HDMI standard.

Sadly, an excess of marketing hype has made shopping for an HDMI cable confusing. There are a few basic things you can look for. First, check for the HDMI logo on the cable's packaging. This indicates that the cable conforms to HDMI specs for its specific length. Next, if you're looking for a future-proof cable that can reliably pass a 1080p-rez signal and also support the 12- and 16-bit depth required for Deep Color display (a feature on many new HDTVs, although no Deep Color-encoded sources are yet available), look for specs like High Speed (Category 2), 340-MHz bandwidth, or a "speed rating" of 3.4 Gbps. (In some cases, this last spec is given as 10.2 Gbps, but both basically mean the same thing, with 10.2 Gbps being a summed figure that includes the red, green, and blue channels in the video signal, as opposed to a single channel).

Have a question for Al? (We mean, of course, related to audio, video, or home theater - he won't tell you when his birthday is.) Drop him an e-mail: soundandvision@hfmus.com (put "Q&A" in the subject line). Please include your name, street address, and phone number for verification; only your name, city, and state/country will be printed. Sorry, but only questions chosen for publication can be answered, and all letters are subject to editing at our discretion.