The latest video processors seek to minimize picture artifacts and expand system capabilities

Jaggies, judder, combing, tearing, mosquito noise, block noise —these are just a handful of the terms to describe picture anomalies that degrade high definition picture quality.

Thankfully, the latest generation of stand-alone scalers/video processors aims to fix all of that.

Video processors, often called scalers, aren’t a new concept. More than a dozen years ago at a CES show, I borrowed a high-end front projection setup to complement a surround sound demonstration. Runco provided a CRT-based front projector (back then, that technology, now defunct, was really the only game in town for top picture quality).

Stewart Filmscreen provided a 16:9 screen and Faroudja loaned one of their video processors. The Faroudja’s principal task was to take the standard-definition, interlaced signal from the laser disc player and de-interlace it to progressive.

Known at the time as a “line doubler,” the Faroudja actually provided the more difficult task of true deinterlacing, and for years was the industry standard for high-end video aficionados. At a price of $15,000 (in mid-’90s dollars), the Faroudja was far from cheap. For the really high-end front projection enthusiast who could afford a true data-grade/HD-capable projector, Faroudja also offered a “line quadrupler,” priced then at a breathtaking $30,000.

Today, upconverting DVD players that output 1080p via HDMI can be had for a pittance, and recent CES 2009 Blu-ray announcements have players coming to market this year for under $200. A raft of high performance video processing chips are now available from a number of chip vendors, allowing improved video processing in both outboard scalers as well as onboard in HDTVs and other video source components, like Blu-ray players.

An external video processor can make a lot of sense for many HDTV owners, as early generation sets didn’t usually feature the kind of video processing prowess that would prevent objectionable artifacts. Many sets featured only one or two HDMI inputs, hindering system expansion capabilities. Other HDTV sets suffer from limited picture adjustments over a range of inputs, which is another area where an external video processor will provide tangible benefits.

Before we get started, if you want a sort of "101" class on all the terms and technology we're talking about, check out Geoff's Definitive Guide to Video Processing.

Lumagen/Sencore RadianceXD

For the die-hard video purist, Sencore (a leading maker of test equipment) has teamed with Lumagen and recently introduced the RadianceXD external processor, which features multiple picture adjustments for each and every input.

The key advantage to the RadianceXD is its ability to precisely tune the video output to the HDTV display and provide the same set of extensive adjustment capabilities for all of the inputs. Sencore’s Tom Schulte demonstrated the box’s extensive tunability in my home, using Pioneer’s Elite Kuro 50–inch plasma HDTV as the test subject.

He checked that the Kuro was properly calibrated (it was), and then calibrated the output of the RadianceXD to exactly match the set. He performed another full calibration round on one of the box’s HDMI inputs from a Samsung Blu-ray player.

The box’s extensive adjustment capability allows an experienced calibrator to fine-tune to an exact degree the optimum picture quality characteristics for each and every video source in a system, with no less than four picture memories and eight resolution sub-memories for each input.

As we migrate from many video wires running to an HD display to the now more common one-wire HDMI hookup scenario, having a processor like the RadianceXD in the system ensures that no matter which input is selected, the picture quality is always tuned properly for best results.

The RadianceXD also provides extensive adjustment control for gamma to ensure that deep blacks and dark gray details are preserved, a common failing of many video displays. At $3,995, the price is entirely reasonable given the extensive connectivity and broad range of adjustment capabilities.

Another benefit to an external processor like the RadianceXD is superior deinterlacing and upconverting. Using multiple Blu-ray test discs, Tom and I confirmed that the RadianceXD is a top-rank performer, sailing through most (but not all) of the 1080i–to–1080p deinterlacing tests.

A 1080i deinterlacing test video on Pioneer’s demo Blu-ray disc has a model airplane with a rapidly spinning propeller, and the RadianceXD stumbled a bit on that clip. That’s a tough test for any processor, and shows that while a particular scaler can achieve stellar results with slow-to-medium motion. Fast-moving image processing might not always be up to par, which is a reason why we rely on testing various displays and external video processors with a wide range of test discs.

DVDO iScan VP50Pro

Another popular range of outboard video processors comes from industry veteran DVDO, which made their name with inexpensive boxes back when laser disc was king (before DVD and Blu-ray, of course). Their top-line iScan VP50Pro model features a video processing chip of their design.

Other models in their range use chips sourced from Silicon Image—not to be confused with Silicon Optix, another video chip vendor. Certified by both THX and ISF, the VP50Pro features fairly extensive connectivity, with four HDMI inputs and two component inputs, along with composite and S-video inputs for older legacy sources.

Running through the various SD and HD moving-image test patterns showed the VP50Pro to be an entirely competent performer, doing slightly better on some patterns, and only slightly less so on others. This performance is consistent with other processors, where the design engineers optimize for certain key parameters they believe to be most important. Avoiding competitive intellectual property disputes is among the considerations that must be taken into account when a company develops their processing algorithms.

One advantage that the DVDO processors provide is onboard test patterns, including single pixel on-off full fields, which is a boon for optimizing a display’s overscan rate. Most displays provide out-of-the-box overscan, to clip off extraneous flicker or line noise that might be viewable (especially notable with broadcast HDTV programs that feature SD segments, such as nightly news shows).

That overscan virtually always results in a softening of extreme detail and can sometimes result in objectionable “ringing” artifacts, which is why we recommend an HD display be set to 1:1 pixel mode. This is usually named Dot-by-Dot or Just Scan, to cite two naming conventions often used by set-makers.

The $3,499 VP50Pro has another differentiating feature that allows an improperly upscaled SD source to be reverse-processed back to its native deinterlaced form and then re-interlaced and upscaled with improved results.

On to Denon, Silicon Optix/IDT, Marvell...