ARRI ARRIFLEX D-21 - Manual (Page 13)

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ARRI | ARRIFLEX D-21 / D-21 HD
CinemaScope in Standard HD
While the D-21 can record the full 4:3 sensor image in Data Mode,
both D-21 and D-21 HD can use the Mscope
TM format which utilizes
a more economical standard HD workflow. In Mscope TM , a regular
anamorphic lens is used on the D-21 or D-21 HD. The camera divides
the resulting 4:3 image into two HD streams: the A-stream contains
the even lines of the original frame while the B-stream contains the
odd lines. These streams are recorded on any HD recorder capable of
recording dual HD-SDI streams. In postproduction the two streams are
recombined to produce a high resolution Mscope
TM HD image. From
then on the project can be treated as a 35mm anamorphic feature,
right up to HD distribution or laser film-out for theatrical distribution.
An added benefit of the process is how easy it is to monitor an
undistorted image of the proper aspect ratio on set. Though the ana-
morphic lens creates a squeezed image, each of the two HD streams
contains only half the lines of that image, so a monitor displaying
either the A or B-link will show a picture of the correct proportions.
The quality of this picture is more than adequate for assessing perfor-
mance, exposure and focus; furthermore, either stream can be used
immediately for off-line editing.
The Mscope TM process divides the anamorphically
squeezed image into two HD streams. Since each
stream consists of half the image lines, the image is
automatically stretched and thus an undistorted
HD image can be previewed on the set and used
for off-line editing.
D-21 / D-21 HD
Anamorphic lens squeezes
the image by a factor of 2
(circles become ovals).
Camera sensor creates a
2880 x 2160 pixel (1.33:1)
Bayer raster image.
Image is reconstructed and
downscaled to a 1920 x
1440 (1.33:1) HD image.
Image is split into two HD-
SDI streams, one contain-
ing the even, the other the
odd lines.
HD RECORDER
Each HD-SDI stream contains
1920 x 720 (2.66:1) pixels of
image content in the 1920 x
1080 HD image.
Any HD recorder capable
of recording in dual stream
mode can capture Mscope
TM
images. Examples: SONY
SRW-1, S.two DFR2K, Codex
Digital.
Each stream contains half the
lines, thus presents an un-
squeezed image (circles are
circles) for on set previewing.
STORAGE MEDIA
Both streams are
stored interleaved
on one tape or data
magazine.
POST INGEST
For off-line editing, only
one stream is used to save
bandwidth.
For image recombining,
both streams can be in-
gested either in parallel or
one after another.
RECOMBINING
After ingest, the two
streams are recombined
and rendered in postproduc-
tion, resulting in the same
anamorphically
squeezed
1920 x 1440 (1.33:1) HD im-
age that was present in the
camera.
The first company to sup-
port Mscope
TM is Quantel
with the Quantel iQ.
FURTHER POST
Images are de-squeezed,
cropped and scaled to the
desired delivery resolution,
for example HD Letterbox or
anamorphic film-out.
2x HD-SDI 4:2:2 2x HD-SDI 4:2:2