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Simultaneous use of 2 usb camera inputs on Windows 10 - driver issue? RRS feed

  • Question

  • I know very little about drivers, and I assume this is going to be a rhetorical question, but here goes.

    On my Win10 laptop, if I have two composite cameras feeding to two external video capture devices, which are connected to the PC via usb bus. Either camera works when operating alone. When they are both running , either one video stream works, and not the other, or, the video streams for both are corrupt.  The 2 video capture devices are using the same driver, but do show up as two distinct devices to the program that displays the captured video. It was suggested by others that the usb bus could not tolerate having the two video streams (NTSC composite) running at the same time. However, I have successfully had 3 video capture devices running simultaneously; they were 3 different types with 3 different  drivers, so I doubt the usb bus or the PC is at fault.

    So I assume that the driver is to blame for the lack of ability to have more than one identical video capture device operating at one time. Is this the root cause? And if so, is there a way around this limitation by writing a program to access the driver/device differently in Win10? As you may suspect, these are generic drivers for $15 video capture devices, so contacting the manufacturer, or expecting updated drivers is a no-go.

    Saturday, April 9, 2016 6:00 PM

Answers

  • what driver is controlling the camera? you can find that out by looking at the properties of the device in device manager. It sounds like a limitation of the driver, but it is not a simple answer. you can eliminate usb bus bandwidth concerns by making sure the two cameras are plugged into two different host controllers. if you view by connection in device manager you can see which controller each is plugged into and experiment with different ports to see if you can get them on different controllers

    d -- This posting is provided "AS IS" with no warranties, and confers no rights.

    Saturday, April 9, 2016 6:41 PM

All replies

  • what driver is controlling the camera? you can find that out by looking at the properties of the device in device manager. It sounds like a limitation of the driver, but it is not a simple answer. you can eliminate usb bus bandwidth concerns by making sure the two cameras are plugged into two different host controllers. if you view by connection in device manager you can see which controller each is plugged into and experiment with different ports to see if you can get them on different controllers

    d -- This posting is provided "AS IS" with no warranties, and confers no rights.

    Saturday, April 9, 2016 6:41 PM
  • Thanks for your response. Unfortunately moving the cameras and their video capture devices to separate usb  controllers does not resolve the issue. And usb bandwith is not an issue, as I can capture 3 cameras and capture cards as long as they use 3 different drivers.

    I guess a follow up question is - are device drivers written differently if they allow multiple devices to run simultaneously, as opposed to allowing only one device to operate at a time? For example, it is not unusual to have multiple hard drives on a pc, while having more than one mouse would be. 

    To clarify, i am working with a standalone camera that sends composite video to a capture  device, and not a webcam. These capture devices are cheap external modules that accept composite video input, and then provide output to the PC via the usb port. They are manufactured in bulk overseas, and are typically sold for under $20 retail. The generic name of the capture devices is Ezcap. The drivers are of unknown origin, and probably just barely worked under XPx32, and there are hundreds (if not thousands) of posts on the internet where buyers can't get it to work under Win7, 8 or 10 (although it works for me under Win10x64 for 1 camera). As such, I don't believe there is a lot of incentive for the manufacturers to update the driver. So we are basically on our own (hence the phrase you get what you pay for).


    • Edited by lewist1957 Saturday, April 9, 2016 11:04 PM
    Saturday, April 9, 2016 11:01 PM
  • each driver is different. usually they allow multiple simulataneous devices. if it is a custom driver you are out of luck unless the vendor will update it

    d -- This posting is provided "AS IS" with no warranties, and confers no rights.

    Sunday, April 10, 2016 6:50 AM