Multiple Webcam Acquisition error

I'm having this problem with the Image Acquisition ToolBox.

I'm trying to capture images from two USB webcams. When I try to preview each webcam separately, there is no problem. But when I try to preview both webcams at the same time I get this error on the second preview:

     Error using imaqdevice/preview (line 177)
     The image acquisition device failed to start acquiring images.

Any idea? I tried to connect my webcams in different USB ports and even whith a PCI USB expansion card and always the same problem.

This is my code (it only previews vid1):

vid1 = videoinput('linuxvideo',1);
vid2 = videoinput('linuxvideo',2);

subplot(211)
h1 = image;
preview(vid1,h1)

subplot(212)
h2 = image;
preview(vid2,h2)

[Tiago]

It looks like that my USB bandwidth is full and even lowering the frame rate to the minimum possible doesn't solve.

Answer 1

[JULIO LOPEZ CASTILLEJOS]

Hi,

I already made a code that made 4 cameras work at the same time, my problem is that when I close the preview windows and try to made the code to work again this error apears and dosen't let me get images, did you fix your problem and/or have an idea of how to fix it?

Thank you for advance and hope you or anyone can help me.

[Tiago]

As I said, my problem was due to USB bandwidth. Adding a new PCI USB expansion to you computer should solve your problem.