Hi, 2011/6/7 Alexey Fisher <bug-tr...@fisher-privat.net>: > On Mo, 2011-06-06 at 17:31 -0700, Carl Michal wrote: >> Hello, >> >> I'm having some trouble with a Quanta integrated webcam. It identifies >> itself as: Laptop_Integrated_Webcam_2HDM, usbid: 0408:2fb1. This is built >> in to a Dell XPS-15 (L501X). >> >> The uvcvideo module works, but the video stutters and has some >> distortions, even at low resolutions and frame rates. >> >> With the Camera Output set to MJPG (in guvcview) "Ignoring empty buffer ..." >> messages occur with most glitches.
I would say the camera is not returning the full frame (or maybe empty ones) for same reason. >> >> If the output is set to YV12, the errors look like: >> >> VIDIOC_DQBUF - Unable to dequeue buffer : Input/output error >> Error grabbing image >> libv4l2: error converting / decoding frame data: v4l-convert: error >> parsing JPEG header: Not a JPG file ? >> YV12 is a format returned by libv4l, and it's obtained by decompressing the MJPG stream, so in fact the camera is still in MJPG format like above. >> With cheese, the video preview looks ok, but video capture is >> unusable - the video stutters badly at low resolution, and the capture >> hangs at high resolution (the program doesn't hang, but after a couple of >> frames no more get captured). > Probably the same situation as above (incomplete or empty frames) You should also increase uvc video verbosity and check dmesg for errors. >From the looks of it I would say you are having some hardware sync issues, did you try all possible resolutions and frame rates ? Do these issues happen in all formats Regards, Paulo _______________________________________________ Linux-uvc-devel mailing list Linux-uvc-devel@lists.berlios.de https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
