iScan Plus Pure Progressive Line Doubler
in a high definition television is a difficult decision for many consumers
given the relatively limited amount of high definition programming material
being broadcasted. Much of the material being viewed on these high resolution
displays is from our current standard definition sources. A new start-up
company called DVDO, Incorporated addresses
this issue with the introduction of their new iScan Plus, PureProgressive
Video Interface unit. Unlike other outboard line doublers, the iScan Plus
is reasonably priced at $699. Don't let the price fool you. This is a serious
image processing unit capable of making significant video quality improvements
to your NTSC source material.
DVDO, Incorporated is a privately-held company that designs, manufactures and markets custom chips and system level solutions for the next generation of digital television and digital video products. Their efforts have produced a remarkable product that was once only available to the wealthy. The new iScan Pure Progressive Display Interface processes a standard NTSC source and generates a progressive scan output for HDTVs and other displays capable of 31.5kHz or higher horizontal scan rates. The iScan unit addresses a well known problem inherent in our NTSC video system, namely interlacing. In addition, the original source material may have been derived from film, computer graphics, or a video camera. The technique used to properly dispay 24fps (frames per second) film as an interlaced NTSC image, is known as 3:2 pulldown. This method maps two film frames into five fields (2 fields = 1 frame) of NTSC video. Computer graphics running 30fps uses a similar technique known as 2:2 pulldown. Since the algorithms applied to the incoming video depends on the source, reliable detection is essential for proper deinterlacing. Indicators on the front panel inform the viewer of the source being detected (film, computer graphics or video).
The iScan Plus features three video inputs (2 S-Video and 1 composite) with auto detection capabilities. The video priority switch on the front panel give the user the ability to prioritize the three video inputs. Indicators display the active input channel.
The iScan is compact and resembles a longer version of my old Audio Alchemy Dac-in-the-Box. The unit does get reasonably hot, so proper ventilation is highly recomended to keep the unit working reliably. The internal multi-layered board looks impressive and resembles some of the best printed circuit boards I have seen. Obviously, great care was taken in laying this design out. Video is received by a Samsung video decoder chip (KSO-127) where Y/C separation (comb filtering) and color demodulation occurs. Digitized component video is then sent to the custom DVDO ASIC (DV-101) for detection and de-interlacing. This is where the major processing begins. The DV-101 stores four fields or two frames of video in SDRAM. This is required for the motion detection algorithms used within the chip. Once the video processing is performed, the digital data is sent to the Analog Devices (ADV-7122) triple 10-bit video DAC. Video exits the iScan Plus through a 15 pin VGA style connector. Additional 6 foot or 12 foot cables are available to adapt the 15 pin VGA connector to five BNCs for RGB/HV or to three RCA connectors for component (Y-Pb-Pr) displays. If needed, the iScan Plus can be configured to output Sync-on-green as well as Composite Sync by setting internal jumpers. This makes the iScan unit compatible with many of the high-end projectors currently available.
The iScan Plus performed excellent on clean sources such as the Sony DVP-S7000 and the Panasonic DVD-A120. Obvious interlacing artifacts seen on regular NTSC video seemed to disappear, especially the jagged edges often seen with vertical movement. The auto detect circuitry had no problem sensing the source material on DVD, laserdisc, S-VHS or standard VHS. However, some noisier sources seemed to confuse the iScan Plus' auto detection. For example, Disney's Lady and the Tramp on laserdisc seemed to cause the unit to jump between Video and Film mode regardless of whether the s-video or composite input was used. This may have to do with the fact the source was animated.
One of the most challenging scenarios for an image processor is on the scrolling credits at the end of a film. Bright moving text on a dark background makes it easy to spot problems with the line doubler. The iScan Plus handled this quite well while minimizing artifacts. There were some situations that seemed to cause the iScan to produce aliasing around still text. I never saw this on moving images and it rarely showed up with DVD sources. Overall, this was rare and didn't seem to affect normal viewing.
DVDO has demonstrated with their new iScan Plus that high quality processing
doesn't have to be expensive. The unit performs as well or better than many
line doublers costing several thousand dollars. While there are higher
performing units available with more feature (i.e. user adjustable settings),
the iScan is clearly one of the best "bang for the buck" image processors
|Review - At a glance|
| DVDO iScan
Plus - Pure Progressive
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