Hi Maybe there are some possible reasons.. 1) dropping by the device because the host is too slow to drain the data, -> use a different host to test 2) dropping by the host uvc driver, -> turn on the trace to maximum to check if there is a drop 3) dropping by the application above uvc driver, -> probably be some timing issues or synchronization issues..don't know how to test, maybe a different application would tell the difference?
Good luck On Wed, Jun 24, 2009 at 5:29 PM, Saint Germain <[email protected]> wrote: > I've tried disconnecting all PCI cards except the USB controler and > using it in different slot, but same results. > I also tried booting with acpi=off but no such luck. > > I will try on another computer this week end. Really strange... I never > had any problem with this USB controler. > > I also have a Philips Toucam Pro (need pwc driver) which if connected > on the same port works correctly without a single dropped frame (but > with a poor definition, something about the previous pwcx module being > reimplemented). > > Maybe some freak combination of motherboard + USB controler + UVC > module ? > > I'll keep you updated this WE. > > Thanks for your help ! > > On Wed, 24 Jun 2009 23:46:11 +0100, Paulo Assis <[email protected]> > wrote : > > > The YUYV fps difference to MJPG, IMHO, can only be caused by the > > frame size. MJPG is compressed so it can be some 10 times smaller > > compared to YUYV. This also indicates that CPU is not a problem since > > MJPG requires a lot more CPU (needs decompressing) > > So if memory is also not a problem, the only thing left is the USB > > connection. > > > > I'm just intrigued by the flickering, even at 20 fps video should be > > acceptable, I'm guessing the driver is dropping some data, in yuv > > case the entire frame as incomplete frames are droped by default, in > > the case of MJPG since there is no way of knowing the complete frame > > size (it varies due to the compression process), you just get part of > > the frame and that causes the ficker. > > > > In any case all seems to point to the usb connection, so I would run > > some tests on that. > > > > Best regards, > > Paulo > _______________________________________________ > Linux-uvc-devel mailing list > [email protected] > https://lists.berlios.de/mailman/listinfo/linux-uvc-devel > -- Best Regards Brian
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