Re: store system w 4-8 cameras ?

[Matt Ion <soundy@xxxxxxxxxxxxxxx>]

I don't think you really want something that records direct to DVD... besides
needing to replace the disc regularly, you'll end up with a big stack of discs
very quickly, and you'll need to label and file and store each one - tracking
down a piece of video later can get complicated!

Comparing "standalone" DVRs vs. PCs is really pointless... most standalone units
still record to hard drives, and many are simply scaled-down PCs running an
embedded OS of some kind.  Their only REAL advantage over PCs is cost.

Any PC can be VERY reliable, as long as you don't cheap out.  Use a
server-quality board and RAID-spec hard drive(s) if you're that worried about
it.  Be sure to provide lots of cooling, especially for the drive(s).  Put the
OS and software on a separate drive from the video data. RAID is fine, but
remember if you're using mirroring, you'll need a twice the actual drive space.
(I find using the smallest available drive, usually 80GB these days, for a
system drive, I section off one partition for the OS and software, the rest for
"export" space, and save any video of incidents there... then if the main video
drive dies, that exported video isn't lost).

Keep in mind that as your framerates go up, your data throughput capacity must
go up as well.  I've built 16-channel, 240fps machines, which allows 30fps for
every two cameras, but found that even with a fairly powerful computer, I've had
to keep the frame sizes small (320x240) to run at full speed, or the computer
will have trouble keeping up, and will suffer from dropped frames (it also makes
the system VERY slow to respond on playback, unless you stop recording first).
You're probably better to run multiple disks in a striped RAID to maximize
available throughput; again, if you don't cheap out on the drives, they'll be
plenty reliable.

Remember that full-motion TV video and film is only 30fps; the difference will
be barely noticeable even at 15fps, and 1-2fps per camera is usually sufficient
for surveillance purposes, and allows you to use higher image sizes (640x480 or
better) and lower compression, for better quality.

BTW, if you really need higher quality, there are high-resolution IP cameras
available (up to 3MP - 640x480 is only about .3MP) that connect to the DVR via
ethernet rather than analog video... take a look at the demos at www.camacc.com

The DVRs I build, I use the VideoInsight system (www.videoinsight.net)



- Bobb - wrote:
> Thanks for the info so far.
>
> If I used a DVR how often to change the DVD ? Every 4/8 hrs ? Is this a
> "plain old DVR " like I'd get at Circuit City/Best Buy ? How to view
> something that you suspect just happened - " how to back up ?" and still
> be recording ?  Would it be one DVR per camera ?
>
> Since I posted the question, I've looked online at systems and played a
> bit with a webcam which generated another question:   Some of the PC
> systems state that they have 4 cameras, a 100-200gb drive , will record
> "X" fps (varies) and they'll hold a month's worth of info on the hard
> drive (and the samples they show look fine). I hooked up a logitech
> webcam on a pc and the video was so-so. In minute it was a 12mb file -
> if it takes 12 mb to record a fair image in a minute, how can these
> systems hold a month's worth of quality video from 4 cameras ??  Is it
> all a matter of the software that comes with the camera system ?  Here's
> some of the stuff I saw online - any opinions ?
> http://spyville.com/digital-video-recorder.html
> http://www.ezwatchstore.com/
> http://www.stardot-tech.com/express6/order_form.html
> RapidOS PCI Wireless Digital Surveillance Card
> http://www.x10.com/cameras/cameras_wired.html
>
> Thanks again for any feedback.
>
> Bobb
>
>
>
> "Bob Worthy" <securinc@xxxxxxxxxxxxx> wrote in message
> news:oDaSg.13091$vi3.3630@xxxxxxxxxxxxxxxxxxxxxxxxx
>
>>
>> "- Bobb -" <bobb@xxxxxxxxxxx> wrote in message
>> news:NIGdnXAD6oUpuoTYnZ2dnUVZ_qydnZ2d@xxxxxxxxxxxxxx
>>
>>> Have a friend looking to buy a convenience store and would like
>>> info/recommendations on a pc-based system that would have 4/6/8 ?
>>> cameras recording to the PC -  in case of  pettty theft/ hold up etc .
>>
>>
>> Where PC's ever really meant to be a security tool? There are inherent
>> reliability issues with using PC's for recording and storing large
>> amounts
>> of video.
>>
>>
>>> He asked me my opinion since I know computers , but other than the
>>> yellow pages/ google etc I don't know how to research this. Since he
>>> brought it up I realized that I didn't know anything about this and
>>> looking to learn.
>>
>>
>> Look at DVR's, of which there are many on the market to choose from. They
>> have all the neccessary features needed for security applications,
>> especially if there is prosecution possiblities involved. Recordings
>> done on
>> someones PC will not usually be accepted except for some initial police
>> investigation.
>
>