Barco XLM H25, Owner'S Manual, Page: 107 / 111

Glossary
GLOSSARY
2:2 pull-down
The process of transferring 24-frames/sec film format into video by repeating each frame (used for PAL DVD’s) as two video fields.
( AD )
3:2 pull-down
Method used to map the 24 fps of film onto the 30 fps (60 fields) or 25 fps (50 fields), so that one film frame occupies three video
fields, the next two, etc. It means the two fields of every other video frame come from different film frames making operations
such as rotoscoping impossible, and requiring care in editing. Some sophisticated equipment can unravel the 3:2 sequence to
allow frame-by-frame treatment and subsequently re-compose 3:2. The 3:2 sequence repeats every five video frames and four film
frames, the latter identified as A-D. Only film frame A is fully on a video frame and so exists at one time code only, making it the
editable point of the video sequence.
Alpha Blending
Alpha Blending enables the ability to add transparency to any selected source.
Artefacts
Undesirable elements or defects in a video picture. These may occur naturally in the video process and must be eliminated in
order to achieve a high-quality picture. Most common in analog are cross color and cross luminance. Most common in digital are
macroblocks, which resemble pixelation of the video image.
Color key
Sometimes also called chroma key. This is a method of combining two video images. An example of chroma keying in action is
the nightly news person standing in front of a giant weather map. In actuality, the person is standing in front of a blue or green
background and their image is mixed with a computer-generated weather map. This is how it works: a TV camera is pointed at the
person and fed along with the image of the weather map into a box. Inside the box, a decision is made. Wherever it sees the blue
or green background, it displays the weather map. Otherwise, it shows the person. So, whenever the person moves around, the
box figures out where he is, and displays the appropriate image.
Common address
Default address. Projector will always execute the command coming from a RCU programmed with that common address.
DHCP
Dynamic host configuration protocol. DHCP is a communications protocol that lets network administrators manage centrally and
automate the assignment of IP addresses in an organization’s network. Using the Internet Protocol, each machine that can connect
to the Internet needs a unique IP address. When an organization sets up its computer users with a connection to the Internet,
an IP address must be assigned to each machine. Without DHCP, the IP address must be entered manually at each computer
and, if computers move to another location in another part of the network, a new IP address must be entered. DHCP lets a network
administrator supervise and distribute IP addresses from a central point and automatically sends a new IP address when a computer
is plugged into a different place in the network.
Projector address
Address installed in the projector to be individually controlled.
RS232
An Electronic Industries Association (EIA) serial digital interface standard specifying the characteristics of the communication path
between two devices using either DB-9 or DB-25 connectors. This standard is used for relatively short-range communications and
does not specify balanced control lines. RS-232 is a serial control standard with a set number of conductors, data rate, word length
and type of connector to be used. The standard specifies component connection standards with regard to computer interface. It is
also called RS-232-C, which is the third version of the RS-232 standard, and is functionally identical to the CCITT V.24 standard.
Logical ’0’ is > + 3V, Logical ’1’ is < - 3V. The range between -3V and +3V is a the transition zone.
RS422
An EIA serial digital interface standard that specifies the electrical characteristics of balanced (differential) voltage, digital interface
circuits. This standard is usable over longer distances than RS-232. This signal governs the asynchronous transmission of computer
data at speeds of up to 920,000 bits per second. It is also used as the serial port standard for Macintosh computers. When the
difference between the 2 lines is < - 0.2V that equals with a logical ’0’. When the difference is > +0.2V that equals to a logical ’1’..
Z-order
The layer sequence in which windows will be displayed in relation to one another.
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