Administrator’s Guide and Operating Instructions
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1.2 Technical Overview
1.2.1 Video Input and Output
The digital video recorder is designed to support either NTSC/EIA or
PAL/CCIR standard. To make the auto detection of video standard
work, at least one camera must be connected to the video input. The
product features video camera inputs with a passive looping output
for each. Camera input impedance termination is set independently
for each camera automatically.
Synchronizing or phasing cameras
is not required to achieve the frame rate of 30 fps for NTSC/EIA
or 25 fps for PAL/CCIR.
Video surveillance and playback is supported by VGA monitor
connection and optional main monitor connections for both
composite and S-video signal formats. The main monitor displays
the selected cameras in any available display format. Another
composite video output is provided for call monitor that displays any
alarm images or the live images of all the installed cameras
sequentially.
1.2.2 Video Processing
The video processor controls the switching of the built-in video matrix
according to the system configurations. The video encoder keeps
analyzing the video signal from the cameras, and encoding the
incoming pictures in JPEG format or MPEG-1 format that is digitized
and smaller in size at 30 fps for NTSC/EIA or 25 fps for PAL/CCIR.
During video playback, the video decoder decodes the digitized
format, no matter it is JPEG or MPEG-1, and then displays the
decoded pictures on the VGA monitor screen or TV monitor screen.
1.2.3 Video Storage and Retrieval
The encoded pictures are stored in the hard disks, with the stored frame
rate for each camera set by the administrator. If any event (Alarm,
Motion, or Video Loss) happens, all the encoded pictures for the
correspondent camera for the preset pre-record duration will be saved
to the hard disk, and the recording rate for that camera will be
changed to its alarm recording rate afterwards for the preset
post-record duration. When the recording reaches the end of the
recording hard disk, the system will automatically switch to the next
available hard disk and record from the beginning of that hard disk.
During video playback, the selected pictures can be saved to floppy
