Minggu, 20 April 2014

Which home security is better?

Q. ADT or Power Home Technologies? Ive heard horrible reviews on ADT but a lot of people have them so im not sure if their actually good or not. Ive never known of anyone to have Power Home Technologies as a home security so i need help on which is better or if there's a better home security company in alabama.


Answer
I'm not familiar with PHT so I'm not sure about their offering. Most security companies use very similar technology and you generally get what you pay for. Part of the decision should be based on what your expectations are. In today's world, with all the police budget cutbacks, the police may not dispatch anyone for a burglary call. If that's the case in your area, you may be further ahead to get an alarm system with a loud siren that you can control. Sounds simple, but these are actually pretty effective. A good watchdog is probably more effective than either company and will probably cost you less. For best value, I think a good intrusion alarm, a watchdog and a pistol is your best bet.

A lot depends on where you live, what type of neighborhood, how isolated is your house, and how much are you gone. If your concern is protecting your house when you're gone, then I'd recommend an intrusion alarm and maybe a simple surveillance camera system. If your concern is for when you are home, then a watchdog and a firearm is a better option.

Surveillance systems will cost about the same as an ADT system. Again, there probably isn't one all around best system as it depends on what you hope to accomplish. I have a surveillance system and a pair of German Shepherds at my home along with several firearms. I've never had a problem.

How much storage space to store the video feed from 500 security cameras for 90 days?

Q. What type of hardware would I need to store that much video data? I want to be able to easily access it, organize it and store it. If I compress it and the video is of exceptional quality, when I retrieve it will it be of the same quality?


Answer
When capturing video I use Xvid4 @ .15bpp and it takes about 250mb for a 40min show. So that comes out to 6.25mb per minute. This includes mp3 audio being captured at 190kbs, so you are probably actually looking at closer to 5.5mb per minute. Also you could use a lower bpp, I use .15 because I notice no quality loss. Anyway.

5.5mb x 60min x 24hours x 90day x 500cams = 356.4TB

even if you were capturing high quality audio you would still only be at about 405TB.

When I am talking about quality I am comparing the image to DVD's at .15 I notice no distortion of the video and it is practically identical to the original.

Now for the hard part; hardware. This is a massive amount of data, if you were to build a storage system using the latest and largest harddrive technology(seagate 750GB perpendicular storage) you would require 534 sperate 750GB hard drives at $420.00 each. Or later this year when seagate releases their 1TB drives then you will need 400 of them.

Now if you can move some of the data to Tapes you can reduce the number of drives greatly and also the size of the recording system. You would have to invest in a very expensive and very fast tape backup drive, which can run upto $3000.00 or more. These drives will allow you to use backup tapes with capacities of 800GB or more and these tapes cost about $150.00 each. With the 800GB tapes you would need 500 of them to store for 90 days.

One thing to realize is that video is already compressed, if it wasn't it would be hugh. So don't pay to much attention to the tapes compressed values.

So your best bet for building a system is to have a system with 10+TB of hard-drive space, which is possible. You want this amount so you can record one entire day of video, then transfer all of that video data to tapes while you are recording the next day ( you will want your software to make 24hr videos for each camera.) One other thing to consider is that you will be recording about 4.5TB per day, this comes to 188GB/HR. While this isn't hugh you will probably want your drives to be arranged in 2 drive clusters running raid 0, just to be on the safe side. This will come in handy when you are trying to access data from that day and when transferring data.

For the rest of the computer(CPU, MEM, etc.) you will want a fairly good system. Top of the line CPU and as much memory as you can fit. Also you will need to purchase equipment that can encode your video on the fly. There are no computers, except for computers that are called Super, that can possibly encode that amount of data on the fly. Encoding is a very intensive process, and with out dedicated hardware can bring even modern systems to their knee's.

Organizing and storing will be fairly easy, just develope a system for tracking tapes by color and/or serial number.

The one part that is up for question is recieving the camera inputs. This would depend highly on your specific system.

Well I hope this helps out.




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