I installed OpenCV-2.3.1a and ffmpeg built with x264. The operating system is Ubuntu 11.04 running on a Macbook Pro 7,1 laptop.
No matter what I do, I can’t get the webcam to work. For example, I tried running the sample code video_dmtx.cpp and I always get the “Failed to open a video device or video file!” error.
I know my built-in iSight webcam and external webcam are working because
ls /dev/video* returns
/dev/video0 /dev/video1
I’ve tested them both out using xawtv -c /dev/video0
To eliminate problems pertaining to multiple webcams, I unplugged the external cam and ran the sample code to see if the default iSight would be detected, but the pointer is still null.
Please help!!!
I fixed the problem!
The camera did indeed work with other software so I knew it wasn’t a hardware issue and had something to do with the installation.
I did a clean install of OpenCV following this guide: http://ozbots.org/opencv-installation/
As mentioned in the discussions at the end of the tutorial, I also did the following to avoid build errors:
1) In step 4 where I installed x264, I replaced ‘–enable-static’ with ‘–enable-shared –enable-pic’
2) In step 5 where I installed ffmpeg, I appended ‘–enable-shared –enable-pic’ to the end of the ./configure command
The camera worked afterwards! I think the problem was that I was missing some packages…
Anyway, hope this helps anyone else experiencing similar problems!