title: How to use multiple USB webcam in Matlab working simultaneously?
body: <p>I would like to take the live video with two USB webcams (Philips SPC 900NC), but I found that they cannot work simultaneously on my laptop. Either of the two USB webcams could work alone or work with another webcam (mounted on my laptop originally). </p>
  
  <p>When I use the simulink block 'From video device', Matlab gave the error message with ' Multiple VIDEOINPUT objects cannot access the same device simultaneously.'. Then I checked the video input device with command 'imaqhwinfo', only one of the USB Philips webcam could be detected. </p>
  
  <p>I would like to know that, </p>
  
  <ol>
  <li><p>what's the reason of this situation? is it because the hardware limitation (USB bus bandwidth) or just matlab video object don't support same multiple video devices?</p></li>
  <li><p>what's the solution of this? could anyone give me some suggestions?</p></li>
  </ol>