AJA KONA 3G, Installation And Operation Manual

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colors of red, green and blue. By using RGB, 2K data can emulate, to some extent, film—which
achieves its color reproduction via red, green and blue layers of emulsion.
The actual 2K image sizes of 2048x1556 and 2048x1080 are usually written in two similar, but
slightly differing, file formats: Cineon or DPX (Digital Picture Exchange format). The Cineon file
format traces it's roots back to one of the earliest “film as digital” devices, the Kodak Cineon. The
Kodak Cineon, introduced in 1992, was a scanner that took film images and translated them into
digital data. Today many devices from a number of manufacturers allow for such a process.
Since files bearing the .cin extension were always related to film, they tend to always be in Log
RGB. Log RGB is a color scheme designed to best approximate the characteristics of film emulsion
in a digital environment. An easy analogy is this: Log RGB is like a “digital film negative” while
linear RGB (usually just referred to as RGB) is like a “digital film positive.” To transform a log RGB
image into a “positive”, Look Up Tables (LUTs) can be applied to the image so that before, during or
after processing the raw image can be seen as it would be if it were a finished product.
As already mentioned, Cineon files are not the only file format that can be used to house the 2K
data. DPX (Digital Picture Exchange) is quickly becoming the standard since being defined by
SMPTE. Like files bearing the .cin extension, files bearing the .dpx extension can be Log RGB, but
they can also be linear RGB.
Cineon and DPX files at full size, 2048x1556 and full 10 bit quality tend to exist as individual frames
that occupy 12.2 MB of data. At 12.2 MB/sec., data rates for a second of video climb to 291.5 MB/
sec. By comparison, the highest quality HD video images rarely exceed 200MB/sec. and most HD
formats use only a little over 100MB/sec. Furthermore, HD material is usually somewhat
compressed in order to be recorded onto tape formats, whereas the 2K data can achieve an
uncompressed status having never had to be recorded onto a tape, but instead directly recorded
onto a harddrive.
If the first major advantage of working with 2K images is their size, then the second advantage is
their handling of color. A 2K color scheme can be used that more closely emulates films properties
than video. Furthermore, this color information need not be compressed due to the limitations of
tape recording, but rather the data can be dealt with as uncompressed.
The Source of 2K Data: Scanning, Telecine and Digital Cameras
Until recently, the only way to acquire a 2K image was to shoot on 35mm film and then scan the
original camera negative (OCN). To be fair, most 2K data is still generated in this method since film
is still seen as the de facto medium for recording moving images for projection at the highest
possible resolution. 2K scanning has persisted as the solitary method of creating 2K data until
recently when a handful of telecine machines have come on the market that can move data at 2K
resolution.
Now we are seeing the first generation of what can truly be referred to as “digital cinema” cameras
as they lack video recording devices, specifically tape recording capability, in their design and
instead concentrate on producing electronic data that aims to emulate the image quality of
traditional photochemical film processes. This era is still early in its development but the pace of
development promises that it will soon draw close to the quality, and in some users opinions, the
ease of use of capturing images to motion picture film.
Transporting 2K Data: HSDL Defined
Moving 2K data is no small task; remember that at 12.2MB/frame, data moves at nearly 300MB/sec.
Storage devices, such as RAIDs or SANs must have very high bandwidth capabilities to handle
recording or playing back data at full speed. The storage devices must also have adequate space
to hold this data as an hour of 2K just exceeds 1 Terabyte.
But storage devices are for storing the data; transporting the data is something different. HSDL
(High Speed Data Link) is easiest for video professionals to understand in this way: HSDL is like
Dual Link HD for the transmission of 2K data. Where Dual Link HD moves across two SDI cables as