Google didn't get me a 'general overview' - just specifics. like:
have pointers to webpages for info on practical differences between using PC based CCTV vs webcams ? To use as security for ( remote ? ) monitoring of a house/store ? ( whether wired or wireless). Nothing specific: I'm just looking to get educated to know the pros / cons of either way.
1.Why would someone choose one method over another ?
2.With CCTV you need to run coax cable ( limit x feet) and with webcams you use 'xx type cable' and the limit is xx feet. Is it mostly cable length the main reason to go with coax ?
If small house/condo does it matter ?
I can see that wireless would be easier to setup, but if not wired cameras, easy for 'bad guys' to jam the signal ?
Recording styles -
Do they both take pictures periodically and save to disk ? Or is CCTV constantly saving?
Recording everything vs recording just an alarm condition ( and how to set it ?)
Is it legal to record audio with a store camera, or this that an invasion of privacy ?
For the PC based stuff, how to setup " an alarm condition?" so that you don't have to be watching the screen and do a screen capture to save the picture? or accidentally overwrite it ?
I can see that 'older versions' recorded to VHS and needed a human to replace the tape, but do non-vhs based systems ( writing to disk rather than tape) overwrite themselves every x minutes ( variable setting) ? And how much disk space to allow for x hours of video ? ( I can see that it would depend on how many cameras/frames per second etc , but how to determine how much to allow)
How about if NOT recording, but want to just have cameras to access your home via internet when desired ... need remote PC online via high-speed and a static IP for that ? again CCTV vs webcams - other than quality any reason for one over another ?
Excellent questions, although they need to be addresses separately and then I'll provide my input from my point of view as a CCTV vendor/installer.
- Bobb - wrote:
A) To keep in line with the rest of the existing cameras. B) Customers don't know the advantages and limitations between systems. C) They choose the cheapest system (and regret it).
A) Webcams are usually limited to a fifeteen foot USB cable. They are very inexpensive, easy to set up...and have terrible quality. B) IP cameras or (ethernet networked) cameras can only be run 330 feet before they need a repeating resource. C) Analog (American NTSC or European PAL standard) cameras can be 400 feet with small RG-59 cable for the clearest picture and up to 1,000 feet for a simply usable picture. If you use thicker RG-11, you can go 800 feet for the clearest picture and 2,400 feet for a usable picture.
RG-59 would be fine for runs under 400 feet.
Wireless is really when you simply can't do it any other way.
Regardless if its a IP or analog camera, the DVR (digital video recorder that records onto a hard drive) can be set to sample periodically, continuously, when an external alarm contact is actuated, or when motion is detected in the field of view.
Some DVRs have external alarm contact inputs
Generally speaking, when the general public passes over the perimeter of your property, they loose any right to privacy. Now if you record imagery that takes places beyond your property line, that can potentially be an issue. Lets take it a step further, have you ever heard of anyone being prosecuted for video taping their kids' football game and the spectators are included in the recording?
When you say "PC based stuff", I'll assume you are referring to a multiport video card that is installed in your desktop computer. I haven't seen one with external alarm inputs, but you can use motion detection with the imagery.
Most DVRs have the option to over-right or not.
That depends on how many frames per second you are capturing, the video quality, number of cameras, etc. If you use motion detecting, you could possibly have months of recording time.
A) You can set up a video web server and view your images from anywhere. But due to the MJPEG compression it won't be as clear as the local raw video feed. This applies to IP as well as analog cams. B) A 3 Mbps DSL line (with a 500 Kbps upload side) is pretty much the minimum you can get by with. C) Many DVRs have embedded virtual static IP applications, if not a simple router like a Linksys (and many others) have such a service built in (dynaip for one), or you can use your own PC based app such as
[rant mode engaged]
Rule Number 1 - Image quality is proportional to the cost of the camera. A $200 camera will nowhere come close to an $800 one.
Rule Number 2 - Bundled packages of four or eight identical cameras are rarely as good as individual cameras with the proper lenses. Eight cameras with a 6 mm lens will have limited near field of view and poor far view. You may often need a mix of 3.5 mm and 12 mm lens cameras.
Rule #3 - Outdoor cameras without an auto-iris will do poorly at noon and after the sun goes down.
With that said, I'd avoid IP cams as they don't have the best quality due to the MJPEG compression. Most can run power with PoE on the ethernet cable, but if you're going to run an ethernet cable, running a separate power cable isn't that big of deal when you use analog cameras. My IP cams have excellent video imagery, but they are not cheap.
IMHO....the best solution is to use a decent analog camera with an auto-iris with an *appropriate* lens with a DVR that can convert the video to network compatible for multipoint viewing in the home or office or internet and still retain high quality imagery an the hard drive when viewed with a local monitor.
You can get pretty good analog cameras with a 3.5~10 mm vari-focal lens and auto-iris for under $300 and a DVR for under $700 with 300 Gig hard drive.
Depends on what is being taped. Generally if it can be seen from public areas in a manner that normally is viewable, then you are good to go. Thus, you can stand on the sidewalk and take pictures of the front of the house. (Or in this case, through the window of your house and across the street). HOwever, if you need to get a ladder to take pictures over the fence, then even if the ladder is on the sidewalk that doesn't count.
My question about audio recording came from a local store owner who knows that I work on computers ( I used to do corporate systems, no security stuff) and asked me about that. He has a coax cctv system in/around his store hooked up to a pc and was wondering if legal to record audio on those cameras. I told him - 'it's your store" ( and was thinking - ' I know they have public cameras/audio on the street in Key West - so it must be legal).
Wireless was mentioned because I have family with a remote condo. Being a condo, they are not allowed to snake wires thru ceilings/halls/walls. After a bad storm there, they were asking me if they could see the inside of their condo if they hooked up some webcams to their PC there. Which got me to thinking .. about how to do it. They don't need high quality ( face recognition) - just to scan left/right and see - any damage ?
Looks like I've got some homework to do later ( I knew it wouldn't be easy), but I've got the time. I'll check out
Reminds me of a Johnny Carson Tonight Show comment about an old lady complaining about her nude neighbors. The policeman said he couldn't see anything, she said if you climbed up this ladder and looked through this hole...
A man was charged in a nearby county for taking pictures or something like that. Never got the details on the case, but would be interesting to follow up.
The law will vary depending on your local jurisdiction, but I think in most cases, you'll find it's LEGAL to record audio, but the audio may not be admissible as evidence in court unless you have signs stating that there is audio recording taking place.
In my experience, that sort of limitation does not apply to video recording. Again, though, that will vary depending on location.
I'd think if there's that much damage, there's a good chance there's no power or internet working either...
D) They let some salesdroid talk them into the system with the greatest profit margin, rather than the one that best suits their needs.
Analog video can be run much farther over twisted pair using video baluns - upwards of 6,000 ft. with active baluns. See
for examples (there are others, such as
MuxLab is just the brand we usually use).
That would be "overWRITE" :)
I swapped out an old Diebold DVR once that stored every shot as a single JPEG... it had well over 8 months of stored images on a 40GB hard drive.
Have to battle with this one all the time. People don't understand why we charge $400+ for a camera and lens when they can get a complete four-camera-and-recorder package at Costco for less.
Or varifocal lenses :)
That only applies to low-res cameras. Check out some of the high-res types, like IQinVision's
1.3MP with MJPEG compression is at least as clear as uncompressed digitized NTSC video, and QIEye cameras are available up to 5MP. Capture, Philips, Bosch and a ton of others are making high-res IP cameras these days.
We've started just pulling a single CAT5 wire, even for analog cameras. Video balun on each end, run power over an unused pair... and you've got room to add another camera, PTZ control, plus the ability to switch over to IP cameras later without needing to re-cable. Costs a little more at this point in time, but saves a ton of headaches later.
Yeah, but that's $1500 camera compared to an $800 camera compared to a $200 camera :)