Maximum Event Marking Duration

[sfeldmann]

"

The maximum amount of time that an archive should be continuously marked as event data before event marking is disabled.
The value should be entered in seconds and the range of values is between (1-86400). The default is 2 hours (7200 seconds).

"

Can you please clarify this with the 2 hour activity window?  What happens if there IS constant activity over that defined window, and when are the files tagged for activity?  Is it only after the stop event and only if the stop event happened within that window?  I would think that it should be programmed such that if a stop event wasnt recieved at the end of the window, it should act as if there was a stop event at that time, and then a new start event.  This would ensure that there was no loss on the motion recordings.  I can think of many scenarios where you would have slow traffic most of the time and want to record only on motion detection, but then for one reason or another lots of sustained motion.  It is at these times where you probably want the archives the most.  I can increase the timer to the max, but again, what happens if motion lasts for more than a day.  What are the negatives about the increased timer?

Thanks,

-Scott.

[David Aicher]

Scott

Maximum event marking duration is essentially a stopgap to prevent continuous recoding if a stop notification from a camera is missed. 

From the 6.3.1 user guide this iw what it says

When motion is detected, VSMS records video until the video source

indicates that motion has stopped. If the motion stop notification from the

video source is not received by VSMS, VSMS marks video with motion for a

maximum event marking duration period (the default period is 2 hours), and

does not mark video again until a motion stop notification is received and

motion resumes. If there are cameras that may capture continuous activity for

long periods, the Maximum Event Marking Duration parameter must be

changed on each VSMS server (see the “Media Server Configuration Page”

section on page 10-24). For example, if a site has an office that is open to

customers from 9:00 a.m. to 6:00 p.m. (0900 to 1800), the maximum event

marking duration should be set to 9 hours to capture constant activity during

that period.

http://www.cisco.com/en/US/docs/security/physical_security/video_surveillance/network/vsm/6_3_1/user_guide/system.pdf

There isn't really any issue with making it longer other than the possibility that you will record more video than expected if a stop is actually missed during that period.  If there are periods where there will be constant motion for more than 2 hours then you will need to set the value to something that makes sense. 

If you have constant motion for greater than a day,  then you may want to look at schedules that will allow you to do loop recording during those days and record on motion when the activity is less.  I am unsure of a scenario where that might happen so a loop equal to the expiration time may be more appropriate anyway.    You will obviously use more storage space here, but if you have constant motion for  24 hours there should be no difference in storage requirements between motion and a loop anyway.

Regards

Dave Aicher