Hello Pierre, I have been chasing a similar issue with running multiple cameras & USB bandwidth limits.
One option I have concidered, but not tried, is to use multiple USB "root hubs", that is with the actual bus controller not the ones you plug in the PC USB port. There are PCI cards which have USB controllers/root hubs so by installing a number of these you should be able to run all the cameras at once. Of cause it's likely you will run into PCI bus issues once you get 5 interfaces running. There could also be problems with the USB drivers not handling multiple root hubs. The other thing to consider is firewire. Very popular with the video people although I've not used it myself. Hope these suggestions are of some use. Regards, Robin On Wed, 9 Jul 2008 16:10:07 +0200, you wrote: >Hello list people :) > >i have been posting about some issues i had a couple of monthes ago. >The company i'm working for was in the need of a system with 5 >webcams, able to shoot simultaneously "objects" from 5 different POVs. >The generated pictures are then used for 3D modeling. > >Big problem, the "object" is a horse, so the total time of shooting >has to be around 10 seconds, not more, because holding a horse still >for more than 10 seconds require super powers, which we don't have (Or >are too expensive, i dont know) :) > >So we bought 5 quickcam 9000 pro, since the required resolution to >have a find 3D mesh is 1600x1200. > >Actually, all the webcams are wired to a single USB hub, and a little >application i have coded handles a very simple queue when the user >presses the "shoot" button. >The application simply calls the uvccapture command, waits for it to >finish, stores the result, and starts uvccapture on the next camera (/ >dev/video0 / 1 / 2 / 3 / 4) and so on. > >The task takes around 18 seconds it's a bit too much. > >So i was wondering... Why not to use two USB hubs to wire the cameras, >3 cameras on the first hub, two on the second, so the application will >be able to shoot two cams at the same time, then again, then the one >remaining? > >So today i coded this workflow on my application, /dev/video0 to /dev/ >video2 on the first hub, /dev/video3 and /dev/video4 on the other. >The goal was to shoot video0 / video 3 at the same time, then video1 / >video4 at the same time, then /dev/video3. >And i was very surprised to see that the system doesn't allows me >simultaneous requests to the driver. > >Is there any solution to that? > >Thanks for your time! >Pierre. _______________________________________________ Linux-uvc-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
