cap_vfw no more working on win10 / opencv3

asked 2016-08-08 04:45:44 -0600

berak gravatar image

since migrating to win10, CAP_VFW seems no more working.

i still get a dialog box, prompting to choose a camera, but 

VideoCapture(-1);

or 

VideoCapture(0|CAP_VFW);

does not open. can anyone side this / double check ?

(i'm not so much worried about using vfw myself, it's more like 99% of opencv's samples use -1 (which again uses vfw) as default for webcam capture, which would leave noobs on win quite puzzled...)

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System win 10 vs2013 debug ocv 3.1

VideoCapture cc(-1); in console windows : 

***** VIDEOINPUT LIBRARY - 0.1995 - TFW07 *****

in capture windows a gray frame

Videocapture(0) in console windows 

***** VIDEOINPUT LIBRARY - 0.1995 - TFW07 *****

SETUP: Setting up device 0
SETUP: Webcam C170
SETUP: Couldn't find preview pin using SmartTee
SETUP: Default Format is set to 640x480
SETUP: trying specified format RGB24 @ 640x480
SETUP: trying format RGB24 @ 640x480
SETUP: trying format RGB32 @ 640x480
SETUP: trying format RGB555 @ 640x480
SETUP: trying format RGB565 @ 640x480
SETUP: trying format YUY2 @ 640x480
SETUP: Capture callback set
SETUP: Device is setup and ready to capture.

Videocapture(0|CAP_VFW) same as VideoCapture(-1)

LBerger gravatar imageLBerger ( 2016-08-08 06:38:33 -0600 )edit

thanks !

(still weird, all your output is from cap_dshow.cpp, and not from cap_vfw.cpp. imho, 0 should call dshow, while both -1 and 0|CAP_VFW should call vfw )

berak gravatar imageberak ( 2016-08-08 07:51:16 -0600 )edit

may be it is due to this line

LBerger gravatar imageLBerger ( 2016-08-08 09:55:58 -0600 )edit

i think, that is only used in the c-api part, the c++ graph follows another path

berak gravatar imageberak ( 2016-08-08 10:15:55 -0600 )edit

No. with VideoCapture cc(0|CAP_VFW); program reach breakpoint

LogPolar.exe!get_capture_debug_flag() Ligne 127 C++
LogPolar.exe!cvCreateCameraCapture(int index) Ligne 187 C++
LogPolar.exe!cv::VideoCapture::open(int index) Ligne 588    C++
LogPolar.exe!cv::VideoCapture::VideoCapture(int index) Ligne 557    C++
LogPolar.exe!main(int argc, char * * argv) Ligne 101    C++

If i set flag to true in console windows I have got

VIDEOIO(cvCreateCameraCapture_VFW(index)): trying ...
VIDEOIO(cvCreateCameraCapture_VFW(index)): result=000001A59EE89CB0 ...
LBerger gravatar imageLBerger ( 2016-08-08 10:59:16 -0600 )edit

ahh, right , thanks again.. will have to think it over ...

berak gravatar imageberak ( 2016-08-08 11:03:08 -0600 )edit
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