Vivotek IP2121 - Manual (Page 72)

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2. bandwidth share,
3. number of users,
4. number of video input is accessed at one time,
5. the complicated objects in view results in larger image file,
6. the level of your PC or notebook which is responsible of displaying images.
In general, the transfer rate in general local network environment can achieve over 200
kilobytes per second and approximately 10 to 20 pictures of normal environment per
second. The general frame size is illustrated in the follow table for reference.
Quality setting
Size of each frame Bandwidth demand for 30fps
Medium 9.3 kbyte 2246 kbps
Standard 11.15 kbyte 2676 kbps
Good 13.76 kbyte 3303 kbps
Detailed 16.35 kbyte 3925 kbps
Excellent 20.3 kbyte 4886 kbps
Q How can I keep Network Camera as private as possible?
A Network Camera is designed for surveillance purpose and has many flexible interfaces.
The user authentication and special confirmation in installation can keep Network
Camera from unauthorized access. You may also change the HTTP port to non-public
number. You can check system log to examine any abnormal activities and trace the
origins.
Q Why can I see image files when I use dir in FTP even if the alarm is not triggered?
A Every time Network Camera starts, it will capture the images as vpre.jpg. If there are
previously saved image files that are not retrieved, Network Camera will keep them until
they are accessed.
Q How will the stored images be processed if Network Camera loses power?
A If user has defined the snapshot interval, Network Camera will capture images
periodically. Once the pre-defined condition is match, the pre-alarm images will be kept
and the current images will be saved. The subsequent images will be stored as
post-alarm stage. User may retrieve these files either by downloading via FTP or direct
Network Camera send them in e-mails. That means after monitoring conditions are met,
Network Camera will keep these image files until user retrieval even if power is lost.
Q If I set Network Camera to send e-mails of images whenever the conditions are met,
will my e-mail account overflow?
A It is recommended to use transient state rather than steady state. For instance, use