QTKit didn't find any attached Video Input Devices

Question

The following error occurs whenever I try to run a simple application to grab frames from the camera of a Macbook Pro 13" (built-in iSight):

QTKit didn't find any attached Video Input Devices!
Warning, camera failed to properly initialize!
Cleaned up camera.

I've tried passing -1, 0 and as parameters to cvCreateCameraCapture() and the cv::VideoCapture object but none worked. It's important to say that I used OpenCV 2.3.1 on this machine for quite a while and it worked fine passing -1 as parameter.

This problem seems to happen with OpenCV v2.4.2 and v2.4.3 on Mac OS X 10.7.5.

Any ideas?

EDIT:

After a little bit of research I found that QTKit is the QuickTime Kit and has nothing to do with Qt. So the next logical thing to do was to disable QTKit from the OpenCV build, and the way to do that is through the flag -DWITH_QUICKTIME=YES, which forces OpenCV to be build with QuickTime for Video I/O instead of QTKit.

Unfortunately this solution didn't work either, since it caused several compiling errors that I don't want to deal with:

[ 32%] Building CXX object modules/highgui/CMakeFiles/opencv_highgui.dir/src/cap_qt.cpp.o
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:75: error: ‘Movie’ does not name a type
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp: In function ‘CvCapture_QT_Movie* icvCaptureFromFile_QT(const char*)’:
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:100: warning: declaration of ‘did_enter_movies’ shadows a global declaration [-Wshadow]
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:67: warning: shadowed declaration is here [-Wshadow]
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:103: error: ‘EnterMovies’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp: In function ‘int icvOpenFile_QT_Movie(CvCapture_QT_Movie*, const char*)’:
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:142: error: ‘ClearMoviesStickyError’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:145: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:161: error: ‘kQTPOSIXPathStyle’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:161: error: ‘QTNewDataReferenceFromFullPathCFString’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:169: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:169: error: ‘newMovieActive’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:169: error: ‘newMovieAsyncOK’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:170: error: ‘NewMovieFromDataRef’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:190: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:190: error: ‘nextTimeMediaSample’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:190: error: ‘nextTimeEdgeOK’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:191: error: ‘GetMovieNextInterestingTime’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:205: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:212: error: ‘GetMoviesError’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:213: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:213: error: ‘GetMovieBox’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:218: error: ‘QTNewGWorld’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:220: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:220: error: ‘SetMovieGWorld’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp: In function ‘int icvClose_QT_Movie(CvCapture_QT_Movie*)’:
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:243: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:247: error: ‘DisposeGWorld’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:248: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:248: error: ‘DisposeMovie’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp: In function ‘double icvGetProperty_QT_Movie(CvCapture_QT_Movie*, int)’:
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:264: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:281: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:281: error: ‘GetMovieTimeScale’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:286: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:286: error: ‘GetMovieDuration’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:300: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:300: error: ‘GetMovieDuration’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:301: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:301: error: ‘GetMovieTimeScale’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp: In function ‘int icvSetProperty_QT_Movie(CvCapture_QT_Movie*, int, double)’:
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:331: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:351: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:351: error: ‘GetMovieTimeScale’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:356: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:356: error: ‘GetMovieDuration’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:370: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:370: error: ‘nextTimeStep’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:371: error: ‘GetMovieNextInterestingTime’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:372: error: ‘GetMoviesError’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:385: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:385: error: ‘nextTimeStep’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:386: error: ‘GetMovieNextInterestingTime’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:387: error: ‘GetMoviesError’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:408: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:408: error: ‘nextTimeStep’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:409: error: ‘GetMovieNextInterestingTime’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:410: error: ‘GetMoviesError’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp: In function ‘int icvGrabFrame_QT_Movie(CvCapture_QT_Movie*)’:
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:441: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:449: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:449: error: ‘SetMovieTimeValue’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:450: error: ‘GetMoviesError’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:458: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:458: error: ‘GetMovieTime’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:462: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:462: error: ‘nextTimeStep’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:462: error: ‘GetMovieNextInterestingTime’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp: In function ‘const void* icvRetrieveFrame_QT_Movie(CvCapture_QT_Movie*, int)’:
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:484: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:494: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:494: error: ‘UpdateMovie’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:495: error: ‘GetMoviesError’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:503: error: ‘struct CvCapture_QT_Movie’ has no member named ‘myMovie’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:503: error: ‘MoviesTask’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:515: error: ‘GetGWorldPixMap’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:516: error: ‘LockPixels’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:517: error: ‘GetPixBaseAddr’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:517: error: ‘GetPixRowBytes’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:523: error: ‘UnlockPixels’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp: At global scope:
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:556: error: ‘SeqGrabComponent’ does not name a type
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:557: error: ‘SGChannel’ does not name a type
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:560: error: ‘ImageSequence’ does not name a type
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp: In function ‘CvCapture_QT_Cam* icvCaptureFromCam_QT(int)’:
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:590: error: ‘EnterMovies’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp: At global scope:
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:609: warning: unused parameter ‘capture’ [-Wunused-parameter]
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:609: warning: unused parameter ‘property_id’ [-Wunused-parameter]
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:616: warning: unused parameter ‘capture’ [-Wunused-parameter]
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:616: warning: unused parameter ‘property_id’ [-Wunused-parameter]
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:616: warning: unused parameter ‘value’ [-Wunused-parameter]
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:853: error: ‘SGChannel’ was not declared in this scope
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:853: error: expected primary-expression before ‘raw_data’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:853: error: expected primary-expression before ‘long’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:853: error: expected primary-expression before ‘long’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:853: error: expected primary-expression before ‘long’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:853: error: expected primary-expression before ‘,’ token
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:853: error: expected primary-expression before ‘short’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:853: error: expected primary-expression before ‘long’
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:853: error: initializer expression list treated as compound expression
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:854: error: expected ‘,’ or ‘;’ before ‘{’ token
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:238: warning: ‘int icvClose_QT_Movie(CvCapture_QT_Movie*)’ defined but not used
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:261: warning: ‘double icvGetProperty_QT_Movie(CvCapture_QT_Movie*, int)’ defined but not used
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:328: warning: ‘int icvSetProperty_QT_Movie(CvCapture_QT_Movie*, int, double)’ defined but not used
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:438: warning: ‘int icvGrabFrame_QT_Movie(CvCapture_QT_Movie*)’ defined but not used
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:481: warning: ‘const void* icvRetrieveFrame_QT_Movie(CvCapture_QT_Movie*, int)’ defined but not used
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:98: warning: ‘CvCapture_QT_Movie* icvCaptureFromFile_QT(const char*)’ defined but not used
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:572: warning: ‘int icvOpenCamera_QT(CvCapture_QT_Cam*, int)’ declared ‘static’ but never defined
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:573: warning: ‘int icvClose_QT_Cam(CvCapture_QT_Cam*)’ declared ‘static’ but never defined
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:609: warning: ‘double icvGetProperty_QT_Cam(CvCapture_QT_Cam*, int)’ defined but not used
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:616: warning: ‘int icvSetProperty_QT_Cam(CvCapture_QT_Cam*, int, double)’ defined but not used
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:576: warning: ‘int icvGrabFrame_QT_Cam(CvCapture_QT_Cam*)’ declared ‘static’ but never defined
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:577: warning: ‘const void* icvRetrieveFrame_QT_Cam(CvCapture_QT_Cam*, int)’ declared ‘static’ but never defined
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:586: warning: ‘CvCapture_QT_Cam* icvCaptureFromCam_QT(int)’ defined but not used
/OpenCV-2.4.3/modules/highgui/src/cap_qt.cpp:853: warning: ‘icvDataProc_QT_Cam’ defined but not used
make[2]: *** [modules/highgui/CMakeFiles/opencv_highgui.dir/src/cap_qt.cpp.o] Error 1
make[1]: *** [modules/highgui/CMakeFiles/opencv_highgui.dir/all] Error 2
make: *** [all] Error 2

Answer 1

I reported this problem but now I think it might be specific to my system, I'll try to perform more tests to clear it up.

Anyway, here's what I had to to fix the issue:

Edit modules/highgui/src/cap_qtkit.mm and jump to line 313 to see the implementation of:

int CvCaptureCAM::startCaptureDevice(int cameraNum) {

Our changes will be made to this method, so locate the following block:

if (cameraNum >= 0) { 
    int nCameras = [devices count];
    if( cameraNum < 0 || cameraNum >= nCameras )   
        return 0;
    device = [devices objectAtIndex:cameraNum] ;
} else {
    device = [QTCaptureDevice defaultInputDeviceWithMediaType:QTMediaTypeVideo]  ;
} 

and replace it by:

if (cameraNum >= 0) { 
    int nCameras = [devices count];
    if( cameraNum > nCameras )
        return 0;
    cameraNum--;
    device = [devices objectAtIndex:cameraNum] ;
} else {
    device = [QTCaptureDevice defaultInputDeviceWithMediaType:QTMediaTypeVideo]  ;
} 

Recompile OpenCV and don't forget to install it on your system again.

Answer 2

Just restart the camera solved the problem. sudo killall VDCAssistant

Answer 3

I had the same problem and I did not find any solution. By trial and error, I found that my OpenCV version is corrupted. As a result, I deleted it and install a new fresh one. You can use one of these two options: 1. Terminal run brew uninstall opencv3 to uninstall opencv then install it using sudo apt-get install libopencv-dev python-opencv command.

2. Anaconda Actually, I used this method for my own problem.

1. open anaconda
2. go to the environment section and select your environment as follow: then click on installed and search for opencv: select opencv package and uninstall it. then try to re-install opencv by selecting not installed and searching for opencv. be careful to install the correct version.