Two webcams

[ds123]

I'm not sure if this is in the right section, so please point somewhere else if necessary.

I have started playing with opencv and I want to use two webcams for this. While one works just fine, I am able to use two only if the resolution is moved from 640x480 to 320x240.

The error that I get with a resolution at 640x480 is:

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libv4l2: error turning on stream: No space left on device.

Now I don't quite know what this means, but I speculate that there is a buffer on USB that needs to be larger than it is.

here is lsusb:

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Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 003: ID 0ac8:3420 Z-Star Microelectronics Corp. Venus USB2.0 Camera
Bus 001 Device 004: ID 0ac8:3420 Z-Star Microelectronics Corp. Venus USB2.0 Camera

I have seen a reference to perhaps needing a separate 2.0 usb bus for each camera.

So, on to the questions.

1. Is there a buffer associated with USB? How can I figure out how large mine is?

2. Can I get out of buying a new motherboard? Is there some usb add-on that would fix my problem?

3. Is there some kernel setting that will enable this to work?

4. If I do have to get a new motherboard, do you have any suggestions for one that will handle it?

Any and all answers greatly appreciated.

Thanks

[k-root]

not enough bandwidth

http://stackoverflow.com/questions/9781 ... v-on-linux

are you running low tech hardware ?

i have a working setup with 2 640x480 camera @60fps on the same usb hub 2.0 with an old intel e5300 , so any recent motherboard should work

[ds123]

not enough bandwidth

http://stackoverflow.com/questions/9781 ... v-on-linux

are you running low tech hardware ?

i have a working setup with 2 640x480 camera @60fps on the same usb hub 2.0 with an old intel e5300 , so any recent motherboard should work

Well, it wasn't low tech a few years ago when I bought it...

I just googled e5300, it looks like it is in the 2.6ghz range, while my processor is a 2.4ghz, so not that much slower, but maybe that is it.

For every thing else I do, it seems snappy enough, but you might right about that. I was also hoping that I could run a similar setup on an old laptop (7 years at this point) for a robot, but I think that idea is dead now.

Thanks for your help, and if you think of any other way out of the dilemma, please let me know.