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16x Analog Cameras, What kind of hardware?
Posted: Wed Nov 12, 2008 11:26 pm
by nitrus10032
I plan on running 16 analog cameras varying from 320x240 to 640x480, mostly the former. Framerates as low as 2.5 are acceptable and I'll need up to 5-10 at times based on motion. I want to run modetect only. I already have a PV-155, so hopefully that can accomplish my goals. I'm not so much concerned with storage as much as I am processor speed, chipset, core count, memory, cache, etc. In fact, if there is a formula any of you guys use, that would be very helpful. Also, on some cameras there will be color capture, probably 4 of them, which will likely be the 640x480 cameras. Any help would be appreciated.
Posted: Thu Nov 13, 2008 5:58 am
by Lee Sharp
To start, you realize that your 640x480 is not really 640 lines, right? Search for "interlace" and read a while... You are paying space for little quality return.
Lets start with the card, as that will determine the rest. You have chips and ports. Each chip can support between 1 and 4 ports, and you can have up to 16 chips. Each chip will also do up to 30 fps, but channel switching looses some frames. All channels on a single chip must be configured identically. In your case, you have a 4 chip, 16 port card. It is a solid card, and I have used several. (Get the heat sinks!) If you want different settings, all of them must be on the same chip. (for example, /dev/video0/0-3) If you can not do this, you will need more chips, like 2 PV-183-16 cards.
Now, at the end, you have the frame rate of you chips. In your case 90fps at 320x240 and 30fps 640x480. Depending on how you set up motion detection, and how much motion you have will dictate your space. I have that card running on 500 gig hard drives, and get between 2 weeks and just over a month.
For the box, start with as much ram as can fit. Seriously... Ram is cheap, and it makes a big difference. The ability to have more buffers never hurts. And while I am still using 32 bit, 4 gig is not unreasonable.
As to CPU, and 2 gig duel core will be fine. A 2 gig single core will work if you cut down the linux install. However, if you want to run FireFox and view on the same box, you will need 3 gig duel core, and will still struggle. Consider xlib_shm if you have to.
Brand is tougher. AMD makes a fine chip, but only Intel makes a full chipset. Many cards have issues with non-Intel chipsets. (Intel is the only one to fully support the PCI spec) So that generally means an Intel CPU.