I am just wondering how many USB cameras can be accessed by one desktop PC? Is there any limit? I am planning to create my own Windows application (using .NET) to capture around 10 USB cameras that are connected to my desktop PC. Is this possible?
The problem is not how many you can discover. On a single USB bus, ~127 could be possible.
But, a USB bus can only transfer a limited amount of bytes per second. So if you want to use more then one, you have to calculate the amount of bandwidth you have for the video stream.
Example : A USB bus normally can deliver realistically ~35 MB/s. 640*480*2 bytes per pixel => 614400 bytes per frame. @30 FPS this is ~17 MB/s, so you can use 2 cameras simultaneously with this setup.
If that Actually, see code for connect 5 cams in to one computer( processor core i3, 8gb ram!!!) you need connect all cameras in to usb ports only on you'r computer!!! git hub link
[Edited]
Actually, see this article which explains: Get List of connected USB Devices
I'm not sure there is a maximum. I will check and post back if I find out.
[Further Edit]
Can't find a documented maximum. Theoretically the ManagementObjectCollection should be able to hold millions of objects in it. If you ran into problems (which I doubt with 10 devices), you could just preallocate the collection size upon instantiation.
I've just ran a test and I can pick up over 10 USB devices through a hub. You should be fine.
Maximum limit for usb devices connected to one host - 127. So, you can connect up to 100+ devices and they would work fine (100+ - because hub is also active device and have own address).
Possibly, you try to access first (already active) camera and program fails, because camera already locked?
来源：https://stackoverflow.com/questions/10239843/how-many-usb-cameras-can-be-accessed-by-one-pc