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The Pre-alarm record mode is the record mode for recording a pre-alarm events event for a specified period before recording an alarm. Pre-alarm record recording is performed at the hot record rate. If you don't specify the hot record rate is not specified, then the recording is performed at the standard record rate.

By default, the recording in this mode is disabled. To enable the pre-alarm recording, do the following:

1. Go to the Hardware tab in the System settings dialog box (1) window.
2. Select the Camera object corresponding to the required camera in the objects tree (2). The settings panel for the selected object is displayed on the right of the Hardware tabobject tree.
3. Go to the Basic settings tab on the settings panel of the Camera object (3).
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4. In the Pre-alarm record field, specify the required time interval (sec) of pre-alarm events event recording (4).
5. Click the Apply button (5).

Information The table provides the information on pre-alarm recording options is given in the table.

In Axxon PSIM, one can make perform pre-alarm recording if the camera is disarmed. One You can do it with the help of the DoReact("CAM","1","REC","rollback<1>") program; (see The Script object. Programming using the JScript language).

Specifying the long pre-record time can result in increasing the waste of running memory. Recommended The recommended pre-record time is not no more than 20s20 seconds.

To count the memory consumption ascertain , figure out the average size of the video signal frame. To perform do this, you must record the video fragment of 500 frames in length to the archive (maximal maximum size on , by default) and use the following formula: 

Frame size = Fragment size / 500

The Note that the frame size is also depends on the percent of motion in the frame.

It is possible to You can count the size of the pre-record buffer for one camera it if the frame size is known:

Size of pre-record buffer for one camera, MB = Pre-record time, sec * Frame frequency in the pre-record mode, fps * Frame size, MB.

General memory consumption in the pre-record mode is defined by the sum of values for each camera.

It is possible to use the following formula in case of If cameras perform pre-record recording with equal frame frequency, you can use the following formula:

Size of pre-record buffer for all cameras in the system, MB = Number of cameras * Pre-record time, sec * Frame frequency in the pre-record mode, fps * Frame size, MB

Configuring video in the pre-alarm record mode is complete.