CPU, GPU / RAM requirements for DIY NVRs

[janos666]

I cannot possible imagine I am not posting an overly redundant thread but I couldn't find the appropriate one, so I guess I have to...

I am personally thinking about buying an ITX board with an Intel J1800 SoC + 2x1Gb DDR3 RAM to run ZoneMinder with 4x 1080p30 cameras.
I don't plan to run any kind of motion detection algorithms in real-time.

Is this a realistic plan?
I have never used any kind of IP cameras before, so I have absolutely no idea what kind of raw x86_64 CPU power I need to record the HD streams and display the SD streams in real-time. Is the GPU speed and/or it's allocated memory size counts at all (above a certain minimum point which can't be a problem with recent hardware...)? Do I need a meaningful amount of system RAM to run ZoneMinder or is it enough to have the recommended amount for the OS itself which grants a little extra above the system usage?

The cameras are on their way from China and should arrive soon. I don't want a huge delay from determining their NVR resource requirements by "trial and error" (which can also be costly if I need to buy and return/sell several boards, modules, etc).

[Nerre]

Without motion detection there's not problem with that setup, what takes computing power is the motion detection.

[marcom]

Without motion detection there's not problem with that setup, what takes computing power is the motion detection.

So as long as there is no motion detection, cpu requirements is modest ...? Thanx, did not read there elsewhere ...

Is there a standard spec for 4 , 8 , 16 camera setups somewhere in this forum ?

[aaronl]

Modest is a relative term. The same job is not so modest for a celeron processor. After trying ZM out on a dual core celeron based machine, and now an i5, with only 4 IP cameras, I can say that the Celeron doesn't cut it. 2 cameras 50% cpu, 4 cameras 100% cpu (at only 3fps).
on the i5, four cameras is only 20% cpu (and I'm increasing the frame frame rate up to 10fps)

hope my experience helps a little bit.
Aaron

[Nerre]

Saving down video (or stills) to disk doesn't take a lot of resources. I had an old HTPC running a 450 MHz Pentium II, it was capable of saving two parallel DVB-T streams to disk while also streaming two already recorded streams for playback. It's just a matter of shoveling data, much of it can be taken care of by DMA.

Image analysis for motion detection is however quite CPU and RAM intensive. Conversion of image or video data also takes a lot of power.