Hi,

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
repeatedly:

VIDIOC_QUERYCTRL: Inappropriate ioctl for device

I also tried the code from

http://linuxtv.org/downloads/v4l-dvb-apis/capture-example.html

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
mt9v032,omap3_isp,v4l2_common
media                          13127               3
mt9v032,omap3_isp,videodev
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.

Thanks,
Bo



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