Sanyo VSP-SV2000P Instruction Manual page 59

Glossary of Terms
Pre-alarm and post-alarm recording
Pre-alarm and post-alarm recording involve
recording data according to a selected ratio in
the video server's internal memory. The default
ratio is pre-alarm = 0 / post-alarm = 10. When an
alarm is detected in this condition, only
post-alarm images are recorded in the video
server's internal memory.
Post-alarm recording is the recording of alarm
data after an alarm has been detected by an
external sensor or motion detector. When an
alarm is detected, the alarm data is recorded into
the internal memory according to the ratio
selected. If the ratio is 0/10, all of the available
memory space is devoted to post-alarm
recording.
Pre-alarm recording sequentially records alarm
images from immediately before the alarm was
detected according to the ratio selected. When
an alarm is detected, images from before the
alarm that fall within the amount specified by the
ratio selected are recorded in the pre-alarm area
of the internal memory.
For example, if the alarm recording area of the
internal memory is set to a ratio of 3/7, 30% of
the available area is devoted to recording
images from immediately before the alarm is
detected. Actual alarm images are then recorded
in the remaining 70%, and the pre-alarm and
post-alarm recordings are treated as a single
alarm event.
When alarm images are played back, the images
can be viewed continuously starting from the first
images recorded immediately before the alarm
was detected. The alarm recording area ratio is
an important point for consideration when
making settings.
(Alarm input)
Post-alarm recording area (10)
(Internal memory: approx. 16 MB)
(Alarm input)
Pre-alarm
recording
area (3)
(Internal memory: approx. 16 MB)
– 58 –
Post-alarm recording area (7)
English