Multi bus USB Card, Multiple Cameras per bus?

Question

I appended a new Q&A to SupportQuestion2006x02x26x203712 but I'll pose it again here and cross link my edits...

Kenneth, You mention a multi bus/controller USB card, can you provide more information on the "special card" that has multiple bus/contollers? I'm trying to find the best solution for this same problem, I have about 6 cameras but can only use 2 at the moment with the two built in bus/controllers. For example does this have one controller with 6 ports, or 6 controllers??

Another interesting potential solution I've run accross is:

• Finally per find "USB bus problems". If you have multiple USB cameras on one bus then it can appear as if ZoneMinder is causing your cameras to fail. This is because the bandwidth available to cameras is limited by the fairly low USB speed. In order to use more than one USB camera with ZoneMinder (or any application) you will need to inform the driver that there are other cameras requiring bandwidth. This is usually done with a simple module option. Examples are usb_alt= for the OV511 driver and cams= for CPIA etc. Check your driver documentation for more details. Be aware however that sharing cameras in this way on one bus will also limit the capture rate due to the reduced bandwidth.

I haven't attempted to set any of these module options but will update this page when/if I discover a way to connect 2 cameras with degraded bandwith. This could be handy in situations where you might have a long chain of expensive repeater cables and want to stick a pair of cameras out at the end of it rather than having seperate cable runs...

-- RyanFulcher - 10 Mar 2007

Machine totally locks up whenever two usb cameras are accessed on the same bus with any application...

Environment

Motion version:	3.2.7
ffmpeg version:	na
Libraries:	ffmpeg, mysql, postgresql
Server OS:	Ubuntu 2.6.15-28-386

-- RyanFulcher - 10 Mar 2007

Answer

Already answered and added to FAQ.

-- AngelCarpintero - 15 Jun 2008