Danbit H.264 DVR User Manual page 39

After dragging an area, right-click the mouse, select "Exit with saving" to
complete the area setup.
Select "Enable All" to set up global masking.
Select "Clean All" to clean the area of the current color in the view.
Select "Exit Without Saving" to go back to mask setup menu and the setting
you just changed will not be saved.
G. IP Cam Audio Setup
If the channel is ticked the sound from camera will be recorded into the playback
video. On the contrary, no sound will be recorded in the playback video of the
channel which is not ticked.
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