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Sharpness, resolution, and color fringing (chromatic aberration)
are also a function of lens quality. Focus and convergence were quite
good in the central area of the screen, but the red focus was not as
good as the blue and green, which resulted is slightly wider red lines
at the sides of the screen. Red fringing/misalignment increased over
the last eighth of the screen width and reached about a half pixel at
the extreme right edge. There was also about a quarter pixel of red
panel vertical misalignment across the screen.
Overall, images were not quite as sharp as they are with the best
single-chip 1080p DLP projectors, but color fringing on bright edges
was rarely visible from normal viewing distances, except on test pat-
terns. However, a lens with better color correction would undoubtedly
yield some sharpness improvement. It is extremely important to
adjust the focus very carefully for best sharpness, and depending on
panel alignment it may be possible to reduce potential color fringing
by slightly favoring the red focus. There was negligible astigmatism
or curvature of field from a 1.75:1 throw ratio.
Color Accuracy
The CIE diagrams show color accuracy for digital YCbCr input
signals compared to the Rec. 709 (HD) and SMPTE-C (SD) colorime-
try standards using u’,v’ coordinates, which provide a more perceptu-
ally uniform presentation of color space than CIE x,y coordinates.
Each primary is oversaturated compared to the standards, but they
are well balanced to produce complementary colors with nearly per-
fect hues. (Hue is the angle, and saturation is the distance from the
white reference.) The primary colors are more oversaturated com-
pared to the SMPTE-C standard-definition primaries because they
have a smaller color gamut.
The projector’s Color control can be used to reduce overly vivid
colors or fleshtones, but it primarily affects the lightness (brightness)
of colors, rather than their saturation. The ideal solution would be a
built-in Color Management System (CMS) to allow the user a choice
of the SMPTE-C, Rec. 709, or native color gamut. Alternatively, at the
2008 Consumer Electronics Show, JVC demonstrated a new external
video processor that includes a CMS tailored specifically for the RS2
(and RS1). They expect to introduce it in the first quarter of this year.
The CIE diagrams measured with digital RGB input signals (not
shown) are virtually identical to the YCbCr CIE diagrams. The YCbCr
to RGB color-decoding matrices are accurate for both standard-defi-
nition and high-definition signals. CIE diagrams measured with ana-
log RGB and YPbPr signals were also nearly identical, which indi-
cates excellent analog signal-channel matching and correct decod-
ing matrices.
Deinterlacing
The RS2 uses a Gennum GF9351 VXP
™
Image Processor for dein-
terlacing and scaling. The 10-bit video processor provides film-mode
(inverse-telecine) and per-pixel motion-adaptive deinterlacing for
standard-definition and high-definition video. However, 480i motion-
adaptive deinterlacing has become virtually irrelevant since most
video broadcasting that we are likely to watch in a home theatre is
now high-definition. Therefore, I no longer comment on that aspect of
projector performance. I’ll discuss 1080i motion-adaptive deinterlac-
ing for broadcast video in the viewing impressions section.
Inverse-telecine deinterlacing for 480i movies is still important
because it will be years before the catalog of available high-definition
movies are sufficient to replace our libraries of standard-definition
DVDs. Inverse-telecine deinterlacing is an ideal process that con-
verts interlaced video transferred from film to progressive video with-
out artifacts or loss of resolution if the processor can stay locked onto
the video’s 3-2 field pulldown cadence. The Gennum processor han-
dled most 3-2 pulldown cadence tests and bad edit tests (disrup-
tions in the 3-2 cadence) for 480i and 1080i, but it doesn’t include
processing to detect other unusual cadence sequences, such as
those used in animation or anime.
I’ve been disappointed with the 480i inverse-telecine deinterlacing
of the Gennum GF9351 because it fails to lock onto the AVIA Pro 3-2
motion test pattern during the slowest vertical movement, although it
works correctly for faster vertical movement. That is often an indicator
that it will not consistently lock onto the scrolling yellow text at the
beginning of Star Wars: Episode IV—A New Hope, which was the
case in my testing of this projector. Even when it did lock to the 3-2
cadence it produced slightly more line twitter on character edges
than an older generation Silicon Image processor, or a standalone
Lumagen HDQ video processor.
Conversely, 1080i inverse-telecine deinterlacing worked flawlessly
on high-definition movies when I forced an HD DVD player to output
1080i signals for testing purposes. There was no visible line twitter,
and vertical detail was sharp and well defined during slow vertical
camera movement. However, for normal viewing you should use
1080p signals when available, to avoid unnecessary format conver-
sions from 1080p native discs.
24 Hz Input
Judder (irregular stuttering motion) is created when 3-2 pulldown
is used to convert 24-frames-per-second film to 60-fields-per-second
interlaced video, or 3-2 frame repetition is used to create 60-frames-
per-second progressive video from film. Most people become condi-
tioned to ignore that jerky motion after years of watching movies on
broadcast television. However, some people are greatly disturbed by
this temporal artifact. Even those accustomed to the judder of broad-
cast movies are usually quick to appreciate the smoother motion pro-
vided by displaying film sources at an integer multiple of the original
24-frame-per-second film rate. Fortunately, movies are stored on HD
DVD and Blu-ray Discs with their original 24-frames-per-second film
rate, and all current players can now output 1080p24 native video.
The RS2 accepts the 1080p24 signals through its HDMI inputs and
displays them at an integer multiple of the 24 Hz frame rate to avoid
judder. I believe this is so important to reproducing the look of film
that I wouldn’t consider purchasing a front projector for a home the-
atre without that ability.
1080i/p Pixel Perfection
The RS2 produced spatially “pixel perfect” images from 1080p60,
1080p50, and 1080p24 HDMI signals. No pixels were blanked, and
each incoming pixel was precisely mapped to a single projector pixel
without scaling. The projector’s Gennum deinterlacing also converted
JVC® DLA-RS2U 1080p D-ILA® Front Projector
ThE ROGERS REPORT
Widescreen Review • Issue 129 • March 2008
6
5/7
“Contrast ratios are improved to unprecedented new heights
... [and] the light output is also impressive.”
#129 JVC REPRINT:Layout 1 2/7/08 1:54 PM Page 6