ROHS SV-HVR2800 series User Manual page 21

resulting in potentially higher quality per frame than at higher frame rates.
The sub-stream uses a constant bit-rate. This makes the video easier to stream over a
network or the Internet.
4.2 Option
Option menu lets you change some aspects of how the DVR will record footage, such
as:

whether the DVR will record a short video before events take place,
 how long after events take place the DVR will continue to record for,
how the DVR will store and divide long recordings into "packs",


whether the DVR will record over old footage to make room for new events.
Overwrite: When enabled, the DVR will
record over the files already stored on the
hard drive. The DVR will always record
over the oldest files on your hard drive first.
Using the overwrite option is advisable, as
the DVR will always be able to record
events as they happen. However, it does
mean that you'll need to get important events off the HDD before they're overwritten.
Pre-Record: While Pre-Record is enabled, the DVR will record a few seconds before
an event occurs. It's a little like making the DVR psychic (but not really - it's actually just
caching a few seconds of video which it adds to event recordings as they occur).
If you're using Motion Detection (recommended) as your primary recording method,
then it's a really good idea to use Pre-Record - sometimes, if a motion event is fast
enough, it might have left view before the DVR can trigger a recording. With Pre-Record,
there's almost no chance you'll miss it.
Post-Record: How long after an event occurs that the DVR will continue to record. It
can be very useful - for example, if an intruder or potential target triggers the motion
detection but pauses in view, then post record being enabled will get a much better look
at them. We think that 30 seconds is a reasonable length for the post-record setting, but
can be higher (the options are 1, 2, 5 or 10 minutes) depending on your unique
circumstances.
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