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How many cams (of the same type) can be used on rasberry pi.

Need to capture 4 streams simultaneously using Zoneminder.

Windows 7 and ispy can not handle 4 cams from same mfg and device driver. 2 of the same type per usb bus is all that can used, at least from what we could figure.

  • I don't have the sources available right now, but I was investigating Zoneminder on a Pi for multiple cameras a while ago. Everything I found led me to believe that it would be to much to ask from the little Pi. – Ghanima Jan 23 '16 at 14:05
  • What frame rate do you need? You may be able to turn down the frame rate and get it to work. I suggest running all the cameras on the same hub to start with; you apear to be running into issues with how the cameras enumerate. I've seen this before where identical cameras have identical serial numbers (plugging them into the wrong combination of ports caused XP to go down and get stuck in a reboot loop, all off one hub worked). – Chris H Jan 26 '16 at 13:23
  • I don't understand what Windows 7 has to do with it? Zoneminder is a linux product. I have been running into the same problem on my Pis - I can connect four cheap USB cameras and see them in /dev but can only read two at a time using the 'motion' software. I don't mind reducing the framerate to avoid bandwidth limitations but it doesn't work, even at one FPS, even though four FPS on one camera works fine. An inexpensive solution for this would be very helpful. – Chris Jenks Jan 27 '17 at 21:39
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There are video grabbers which can forward video from 4 analogue cameras into single USB port. Grabbing is software multiplexed, so don't expect more then few frames per second.

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This will depend as much on the webcam hardware, drivers, and software as much as it will on the Windows machine or Raspberry Pi.

I can't say for certain without running some tests, but I'd be surprised if the RPi (1 or 2) had the CPU power to handle more than one camera simultaneously. Under certain conditions you might be able to handle 2, but 4 just isn't going to happen.

Your project sounds like it needs some fairly specialized hardware. I doubt a single hobbyist board is going to cut it.

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