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<progressive counter>_<time offset relative to alarm frame>.bmp
</pre>
The first part is a progressive counter, starting from 000000. In other words, the image whose file name is something like 000000_x.bmp refers to the frame captured at the time t<sub>B</sub>. At the other end, the image whose file name starts with the highest counter refers to the frame captured at the time t<sub>A</sub>. This scheme is convenient for automatically processing the frames because it allows to order them very easily.
The second part of the image file names is the relative time offset (expressed in seconds) with respect to the "alarm frame." The alarm frame, in turn, is the first frame captured after the detection of an alarm signal. In other words, it is supposed to be the closest—temporally—to the event causing the alarm. Consequently, the alarm frame is always named as <code>n_+0.000000000.bmp</code>. In the example shown above, the alarm frame's name is <code>002424_+0.000000000.bmp</code>. This rule allows to determine immediately how close is a frame to the alarm event. For instance, see the following image.
The frame shown was captured about 1.58s before the alarm event.
The subdirectory used for this example cointains around 3300 BMP files, as the alarm time window is 11 seconds and the frame rate is 300fps: