• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 97 subscribers
  • Views 581 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

V4L2 Capture on DM8148 USB webcam

markus.hofstaetter
Intellectual 935 points

Hi Everyone!

Ubuntu 10.04 (lucid), PSP 4.00.00.05, Camera Logitech C905, no desktop or window manger or graphical x-session,  (minimum)

kernel 2.6.37 (PSP)

Now to the problem. When using uvcview I can get a single snapshot. According to ffmpeg the camera supports streaming so I thought I'd try to capute a video stream.
When using one of the following commands I either get an error or none, but in both cases no video is recorded. I treid to find the source of the error but I've not been able to
find it so far.

Here the log from mencoder 7026.error.log
Here the command I tried (which works fine on the host computer):

mencoder tv:// -tv device=/dev/video0:buffersize=1024:driver=v4l2:noaudio:fps=15  -ofps 15 -nosound -ovc lavc vcodec=mjpeg -o test.avi

Any suggestions?

Regards

Markus

  • 0
    Intellectual 935 points

    UPDATE: DM8148, Logitech C905 (USB) Webcam, Ubuntu 10.04 (Lucid), 2.6.37 PSP kernel with (uvc support).

    I've written a sample v4l2 application trying to check if there is a problem with the tools or something else.

    So my application opens the driver, requests three mmap buffers, queues them and turns streaming on. Then I just deque and queue  in a loop.
    (640x480, YUYV pxfmt).

    Doing this on my host machine I have no problem (Ubuntu 11.04 (Natty)). Also if I use this sample program with Full HD resolution on the Board for video1 (HDMI) this works fine (output in this case).

    But when I use it on the DM8148 board to capture from the Webcam it stops/hangs/blocks after the first Dequeue event has been sent.

    I can only supply this additional log: 0131.dmesg.log

    Help appreciated.

    Regards Markus

     

    EDIT: If I use O_NONBLOCK, I get EAGAIN all the time (Resource temporally unavailable).

  • 0 in reply to markus.hofstaetter
    Intellectual 935 points

    Hi,

    Has anyone suggestions for my problem mention in the previous posts?

    I wanted to enable kgdb to look further into this problem but it won run on ttyO0 (no such device). I've looked on the internet and found out the some people experience the same problem, i.e. kgdb is incompatible with recent name change from ttyS0 to ttyO0. Is there a way to revert that change or to overcome that problem?

    Regards

    Markus

  • 0 in reply to markus.hofstaetter
    Intellectual 935 points

    UPDATE:

    It works with another USB camera. But after sometime it may not work anymore (e.g. open or buffer allocate, looks like the either the device drivers (v4l2 or USB) might have a bug, because sometimes also a kernel message appears: "timusb dma busy" on the console. Or reset to initialize usb again ...

    I'll keep you updated if something new happens. We also had to insert a USB cable of our own (USB FM to USB mini male). Might contribute to that bug.
    For now I consider this as solved. Altough it would be nice if someone knows if that C905 is buggy with this kernel / uvc version.

    Regards

    Markus