Dahua XVR User Manual page 201

Please refer to the following sheet for detailed information.
Parameter
Snapshot type
Image size
Quality
Interval
Copy
4.8.1.3.3 Video Overlay
The video overlay interface is shown as in Figure 4-25.
Figure 4-24
Function
There are two modes: Regular (schedule) and Trigger.
 Regular snapshot is valid during the specified period you
set.
 Trigger snapshot only is valid when motion detect alarm,
alarm or local activation alarm occurs.
tampering
It is the same with the resolution of the main stream.
It is to set the image quality. There are six levels.
It is to set snapshot frequency. The value ranges from 1s to 7s.
Or you can set customized value. The max setup is
3600s/picture.
Click it; you can copy current channel setup to other channel(s).
Figure 4-25
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