USB Webcam does not work in the newer version: 4.7.0.72

[gunarakulangunaretnam]

USB Webcam does not work in the newer version: 4.7.0.72

I wrote a simple script to read frames from a webcam, it works fine with laptop-attached webcams. When I try to use with the USB-based webcam (not-branded webcam), it returns the following error.

[ WARN:1@2.601] global cap_msmf.cpp:1759 CvCapture_MSMF::grabFrame videoio(MSMF): can't grab frame. Error: -2147024809

My Code:

import cv2


cap = cv2.VideoCapture(2)

while True:

    
    ret, frame = cap.read()
    

    if ret:

        cv2.imshow('Input', frame)
    else:
        print("dsd")

    c = cv2.waitKey(1)
    if c == 27:
        break

When I install the older version of OpenCV-python: 4.5.5.62, it works fine, I think the issue is with the newer release.

Please take a consideration on it.

[asmorkalov]

could you run the same code with old and new OpenCV versions with debug options and collect logs. To enable debug logging you need to set the following environment variables OPENCV_LOG_LEVEL=DEBUG, OPENCV_VIDEOIO_DEBUG=1

[harshkasat]

I'm also getting this error with the USB webcam. Does anyone have a solution regarding this?

[asmorkalov]

Please try the previous recommendation to give us information for debugging.

[asmorkalov]

Please try the previous recommendation to give us information for debugging.

[Maculapse]

Hi! I can confirm the same problem with 4.8.x version using usb cam. Had to downgrade to 4.5 to get it working, as mentioned by the author.

[asmorkalov]

@Maculapse could you run the same code with old and new OpenCV versions with debug options and collect logs. To enable debug logging you need to set the following environment variables OPENCV_LOG_LEVEL=DEBUG, OPENCV_VIDEOIO_DEBUG=1

[ArptPlank]

我也是4.8版本也遇到这个问题，自己的电脑上没问题，在客户的电脑上死活不行

[polar147]

@asmorkalov i have the same issue. this is the output with debug env var:

[DEBUG:0@0.021] global videoio_registry.cpp:225 cv::`anonymous-namespace'::VideoBackendRegistry::VideoBackendRegistry VIDEOIO: Builtin backends(10): FFMPEG(1000); GSTREAMER(990); INTEL_MFX(980); MSMF(970); MSMF(960); DSHOW(950); CV_IMAGES(940); CV_MJPEG(930); UEYE(920); OBSENSOR(910)
[DEBUG:0@0.028] global videoio_registry.cpp:249 cv::`anonymous-namespace'::VideoBackendRegistry::VideoBackendRegistry VIDEOIO: Available backends(10): FFMPEG(1000); GSTREAMER(990); INTEL_MFX(980); MSMF(970); MSMF(960); DSHOW(950); CV_IMAGES(940); CV_MJPEG(930); UEYE(920); OBSENSOR(910)
[ INFO:0@0.039] global videoio_registry.cpp:251 cv::`anonymous-namespace'::VideoBackendRegistry::VideoBackendRegistry VIDEOIO: Enabled backends(10, sorted by priority): FFMPEG(1000); GSTREAMER(990); INTEL_MFX(980); MSMF(970); MSMF(960); DSHOW(950); CV_IMAGES(940); CV_MJPEG(930); UEYE(920); OBSENSOR(910)
[ WARN:0@0.045] global cap.cpp:406 cv::VideoCapture::open VIDEOIO(GSTREAMER): trying capture cameraNum=0 ...
[ INFO:0@0.050] global backend_plugin.cpp:382 cv::impl::getPluginCandidates Found 2 plugin(s) for GSTREAMER
[ INFO:0@0.058] global plugin_loader.impl.hpp:67 cv::plugin::impl::DynamicLib::libraryLoad load C:\Users\andrei\Desktop\Parachoque\.env\Lib\site-packages\cv2\opencv_videoio_gstreamer4110_64.dll => FAILED
[ INFO:0@0.061] global plugin_loader.impl.hpp:67 cv::plugin::impl::DynamicLib::libraryLoad load opencv_videoio_gstreamer4110_64.dll => FAILED
[ WARN:0@0.064] global cap.cpp:468 cv::VideoCapture::open VIDEOIO(GSTREAMER): backend is not available (plugin is missing, or can't be loaded due dependencies or it is not compatible)
[ WARN:0@0.068] global cap.cpp:406 cv::VideoCapture::open VIDEOIO(MSMF): trying capture cameraNum=0 ...
[ INFO:0@0.089] global cap_msmf.cpp:1033 CvCapture_MSMF::configureHW MSMF: Using D3D11 video acceleration on GPU device: Intel(R) HD Graphics 4600
[DEBUG:0@0.213] global cap_msmf.cpp:916 CvCapture_MSMF::initStream Init stream 0 with MediaType (640x480 @ 30) YUY2
[DEBUG:0@0.216] global cap_msmf.cpp:916 CvCapture_MSMF::initStream Init stream 0 with MediaType (640x480 @ 30) MFVideoFormat_RGB32
[ WARN:0@28.224] global cap.cpp:418 cv::VideoCapture::open VIDEOIO(MSMF): created, isOpened=1
[DEBUG:0@28.227] global cap_msmf.cpp:534 `anonymous-namespace'::SourceReaderCB::Wait videoio(MSMF): waiting for frame...
[ WARN:0@38.236] global cap_msmf.cpp:1795 CvCapture_MSMF::grabFrame videoio(MSMF): can't grab frame. Error: -2147483638
Traceback (most recent call last):
  File "C:\Users\andrei\Desktop\Parachoque\parachoque.py", line 8, in <module>
    hsv = cv2.cvtColor(frame,cv2.COLOR_BGR2HSV)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cv2.error: OpenCV(4.11.0) D:\a\opencv-python\opencv-python\opencv\modules\imgproc\src\color.cpp:199: error: (-215:Assertion failed) !_src.empty() in function 'cv::cvtColor'