User guide

SerVision MVG 400 System Guide
Configuring the MVG 400 111
for the video stream that is to be recorded. Recorded video can be downloaded from the hard
drive for viewing and saving on the client.
The available space on the hard drive limits how much disk space can be allocated for each
recorder. You can choose what should be done when the disk space allocated for a recorder is
used up: either the earliest part of the recording is discarded and overwritten by the current
recording, or recording stops until you erase the recordings manually.
Video can be recorded continuously or only when triggered by events. Event-triggered
recording can be used to minimize disk usage, so that more time can be covered by a recorder
before its allocated disk space is used up. For example, a second of high-quality recording
requires about 16 KB of disk space. For a full day of high-quality video recording, this
translates into 1.3 GB of disk space. By contrast, if there are 25 events in a day, and the
recorder records 20 seconds for each event, only 8 MB of disk space are needed for the day.
VMD, sensor and activator events can function as triggers for event-triggered recording. Each
recorder can be configured to respond to VMD events detected by the camera from which the
recorder records or from any of the sensors connected to the MVG 400.
When an event occurs, it is often useful to see what happened immediately before and after it.
For this reason, event-triggered recording can be configured to record a set number of seconds
before and after each event (“pre-alarm” and “post-alarm”). To accomplish this, the
MVG 400 always records the specified number of pre-alarm seconds, and then discards this
data if no events are detected. For example, if the pre-alarm is five seconds, the system
always stores the last five seconds of video. If an event is detected, this video is saved as the
pre-alarm recording. Otherwise, it is deleted. The total recording time for each event is the
sum of the pre-alarm time, the time of the event itself, and the post-alarm time.
Another way you can control the disk usage is through the recording quality settings. The
system supports three standard quality levels, high, medium, and low. The lower the quality
setting, the less disk space is required for each second of recording. Obviously, some stream
quality is lost when lower quality settings are used. All three standard quality settings produce
recordings in SIF resolution (320x240 pixels). High quality is the optimal recording
configuration, and is recommended for use whenever possible.
Configuring Video Recording
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To set up video recording for a camera:
1. In the Camera configuration screen, under Recording Type, select the desired type of
recording, as follows:
• Continuous: Recording takes place all the time, regardless of whether events occur
or not
• By Event: Recording only takes place when an event occurs
• None: Recording is not activated for the camera
If you select By Event, the fields required to configure the event-triggered recording are
added to the screen: