I don't know about opencv, but I think the v4l2 example from the link actually told you what happened. The camera doesn't support mmap. Try --read or --userp argument instead.

On Fri, Apr 4, 2014 at 11:38 AM, bowu86 <bowu86@gmail.com> wrote:
Dear all,

I am now having a problem with getting a frame from the Caspa camera in
Opencv on gumstix.

I have a FireStorm gumstix and Linaro operating system that is purchased
from gumstix website. Previously I was able to use media-ctl to set up the
pipeline and get snapshots from Caspa (/dev/video6) using mplayer even
though the pictures looked a little bit green-ish.

My goal is to use Caspa in Opencv and do some onboard image processing. But
now I cannot get a single frame from Caspa in Opencv. I did a lot of search
but was unable to figure out a solution.

I tried

  CvCapture *capture=cvCaptureFromCAM(6);

But when I run the code, what I got was the following message showing

VIDIOC_QUERYCTRL: Inappropriate ioctl for device

I also tried the code from


What I got is

/dev/video6 does not support memory mapping

Run lsmod in command line I can see the following:

Module                  Size                        Used by
ipv6                         258125                    8
libertas_sdio            17341                    0
libertas                   101798                    1  libertas_sdio
cfg80211                175549                   1 libertas
rfkill                           17776                   1 cfg80211
mt9v032                      7401                  1
lib80211                      5134                  1 libertas
firmware_class           7173                  2 libertas_sdio,libertas
omap3_isp              138629                 0
v4l2_common             8746                 2 mt9v032,omap3_isp
videodev                    99516                3
media                          13127               3
ads7846                     11041               0

I believe getting a frame from Caspa in Opencv on Gumstix should be
accomplished before. Could someone who has done it share with me how or
where to look? Any suggestion is greatly appreciated.


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