Enrico, Most logitech uvc cameras support yuv on usb1.1 but only for very low resolutions. This is a bandwidth issue, usb1.1 just doesn't have the necessary bandwidth needed by yuv format on any usable resolution.
Best regards, Paulo 2009/5/15 Enrico Di Lello <[email protected]> > Paolo, thank you very much for your advice, I never thought about this > before. > The FoxBoard has only 2 usb 1.1 ports, so this could actually be the > problem. > So this seems to be a camera related issue, ans I don't know if I > should relieved or just sadder. > > I don't have particular problems in changing camera, the question is > that is hard to find a recent camera supported by a driver different > than uvc. The FoxBoard has native support for pwc and cpia, but this > drivers only support old cameras. > > If the problem is USB related, how could I try to fix it? Is it > possible to trace somehow the handshaking process between the camera > and the driver? I found something like UVC_TRACE in the driver code... > maybe this could be a way. > > Do you know any uvcvideo camera that support YUV and usb 1.1?? > > Thank you again! > > Enrico > > > 2009/5/15 Paulo Assis <[email protected]>: > > Enrico, > > Does the FoxBoard supports usb 2.0 or 1.1 ports? > > Some cameras only enable yuv format when connected to a usb 2 port. > > > > Best regards, > > Paulo > > > > 2009/5/15 Enrico Di Lello <[email protected]> > >> > >> Hi Laurent, > >> > >> thank for your early reply. I don't know if I should send this mail in > >> the mailing list or directly to you. > >> I think that my problem is pretty simple, and since your name is on > >> the comments of the uvc_video source code, I think you're the best > >> person I could ask for help . > >> > >> I did not manage, for now to compile the mercurial package for my > >> system, but I managed to compile the r261 version from the berlios > >> repository. I wrote a simple application to grab a frame from a camera > >> in YUV422 format. > >> > >> The problem is: this application I wrote works just fine on my ubuntu > >> laptop with uvcvideo (Mercurial repository). Camera recognized, YUV422 > >> format set, frame grabbing runs just fine. > >> > >> When I connect the same webcam ( Creative Optia ) on my FoxBoard, the > >> system does recognize the camera, because I can see it in dmesg. > >> > >> When I run the same application, I receive an error when trying to set > >> the YUV422 format. More precisely, the VIDIOC_S_FMT fails when > >> requiring this format. > >> > >> Surprisingly, it successfully sets the format if I choose the MJPEG > >> format. > >> > >> From the source code (of r261) I can see that the YUYV is supported, > >> so I dont'understand why my application should'n work with the same > >> camera on a different architecture. Another application (uvcstreamer) > >> that grabs frames in MJPEG format just works fine on FoxBoard... > >> > >> Why should I disable the V4L support from my kernel? I did so, and > >> compiled everything again, but now I actually get the error msg when > >> launching VIDIOC_REQBUFS the ioctl. Again, same code and same camera > >> work fine on Ubuntu with kernel 2.6.24, while on my FoxBoard I have > >> the 2.6.25. > >> > >> Many thanks to anyone who will help me with this. > >> > >> Enrico > >> _______________________________________________ > >> Linux-uvc-devel mailing list > >> [email protected] > >> https://lists.berlios.de/mailman/listinfo/linux-uvc-devel > > > > >
_______________________________________________ Linux-uvc-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
