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Digital Video Recorder User Guide
116
Digital Video Recorder User Guide
117
Term Denition
4 CIF
A videoconferencing format that specifies data rates of 30 fps with each frame
containing 704 horizontal lines by 576 vertical lines.
4CIF is 4 times the size of CIF. See CIF.
AC
Alternating Current, a form of electricity for powering an appliance. The SVR-
1680/1660 supports either AC or DC current.
AC/DC A power supply offering Alternating Current and Direct Current.
Access Control
An external device for which the SVR-1680/1660 can retrieve text data related to
recorded events. Access control devices provide data related to building ingress
and egress.
Alarm
An input signal event that triggers the opening or closing of a switch that is
connected to a video channel on a DVR. A corresponding response varies
depending on equipment type. Most commonly, a switcher “holds” on the camera
corresponding to the alarm input.
Alarming
The ability of CCTV equipment to respond to an input signal, normally a simple
switch closure. The response varies depending on equipment type, the most
common of which is for a switcher to 'hold' on the camera corresponding to the
alarm input.
Analog
A signal in which any level is represented by a directly proportional voltage; not
digital.
ATM
An ATM (Automated Teller Machine) provides data related to bank transactions. It
is an external device for which the SVR-1680/1660 can retrieve text data related
to recorded events.
Auto Sequencing/
Sequencing
The act of displaying video from every camera, or a group of cameras, that is
connected to a DVR. After a predetermined interval, the DVR displays video from
the next camera in sequence. If 16 channels are connected, the DVR briefly
displays video from cameras 1 through 16 consecutively.
Automatic
Brightness Control
The self-acting mechanism in display devices which controls brightness of the
device as a function of ambient light.
Automatic Gain
Control (AGC)
An electronic circuit that automatically adjusts the gain of a signal as a function of
its input or other specified parameter. For the SVR-1680/1660, AGC controls the
input range of video signals from a camera.
Auto-Terminating
Feature whereby the equipment automatically selects the correct termination
depending on whether the video output BNC is connected.
AVI
Audio Video Interleave. A standard video file format introduced by Microsoft. AVI
files can contain both audio and video, which can be played back synchronously.
Brightness A function of ambient light.
CD-R
Compact-disc recordable. A CD-R disc can be written once and then read many
times.
Term Denition
CIF
Common Intermediate Format. A videoconferencing format that specifies data rates
of 30 fps with each frame containing 352 horizontal lines and 288 vertical lines.
Other related file formats include:
· QCIF (176 x 144) QCIF stands for Quarter CIF
· 4CIF (704 x 576) 4CIF is 4 times the size of CIF.
Continuous
recording
The act of recording video continuously without regard to alarm events or other
settings. When a DVR records continuously, it overwrites older video unless that
video has been marked for retention.
Contrast
The range of light and dark values in a picture or the radio between the maximum
and the minimum brightness values.
Covert channel
A video channel that can be recorded, but whose video can be viewed only by
users with the appropriate permissions.
D1/half D1
A type of video resolution.
· D1 resolution is recorded at 704 x 480 horizontal and vertical lines.
· Half D1 is recorded at 704 x 240 lines.
Data retention
The length of time that recorded video is stored on internal hard disk storage
before it is overwritten.
DST
During Daylight Saving Time clocks are advanced by one hour, in most areas of the
United States. Setting son the SVR-1680/1660 can adjust time to allow for DST.
DC
Direct Current. A unidirectional electric current that provides power to appliances.
The SVR-1680/1660 supports both DC and AC power.
D-I/O Digital Input/Output connections. Also referred to as Digital I/O.
Duration
Refers to any of the following recording periods:
· Total length of recorded video that is stored on the hard disk;
· Length of a specific recorded event including pre-and post-sensor recording;
· Length of the video that should be copied to external media or storage.
DVD-R
Digital video disc-recordable. A DVD-R disc can be written once and then read
many times.
Dwell time
A variable length of time that a channel is displayed on a monitor before another
channel is displayed. See also Auto Sequencing.
eSATA External serial ATA hard disk drive. Supported by the SVR-1680/1660.
Event recording
The act of recording video based on the occurrence of a sensor event or motion
detection. When the SVR-1680/1660 is set to record video based on an event, it
records the video along with pre- and post-sensor activity based on the configured
settings.
Event screen
A group of cameras that are assigned to each other and are displayed
simultaneously upon the occurrence of an alarmed event.
Appendix E. Glossary