** Description changed: Hi, I am trying to make my first application in C++ with OpenCV, where I am trying to capture images from the built-in webcam on my Lenovo T450s. I use Eclipse CDT as my IDE to write code and debug. During several trials, sometimes I need to STOP running applications via Eclipse (probably through some interrupt signal). Whenever the application is interrupted, during the next run it cannot access the webcam and is returning "VIDIOC_STREAMON: Invalid argument" Apparently this is because resources are not released due to the interrupt. Also VLC cannot access webcam after I start seeing this error. Apparently there are 1-2 reports about this issue related to OpenCV and kernel, and there is also a workaround by handling SIGINT properly and correctly exiting. I could not work that solution in Eclipse, because probably Eclipse STOP button does not send SIGINT but some other signal. Nevertheless, I was expecting kernel to handle this in another way, so that resources would be released automatically to allow other applications to access webcam. However, webcam cannot be accessed after a program is interrupted. lsb_release -rd Description: Ubuntu 14.04.3 LTS Release: 14.04 uname -r 3.13.0-68-generic References: http://answers.opencv.org/question/28929/acquiring-video-from-webcam-problems/ http://askubuntu.com/questions/683327/libv4l2-error-turning-on-stream-invalid-argument-vidioc-streamon-invalid-argu https://lawlorcode.wordpress.com/2014/04/08/opencv-fix-for-v4l-vidioc_s_crop-error/ http://ubuntuforums.org/showthread.php?t=2298140 Please don't hesitate to ask for more information about the issue and correct me if my report isn't useful or sufficient. + + Update: After further testing, I realized Eclipse is sending SIGTERM + signal, which if handled does not cause above mentioned issue. However, + a program may still crash or terminated without handling it properly. + This should not cause any issue for other applications.
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to v4l-utils in Ubuntu. https://bugs.launchpad.net/bugs/1518726 Title: Webcam cannot start after interrupted access with "VIDIOC_STREAMON: Invalid argument" Status in v4l-utils package in Ubuntu: New Bug description: Hi, I am trying to make my first application in C++ with OpenCV, where I am trying to capture images from the built-in webcam on my Lenovo T450s. I use Eclipse CDT as my IDE to write code and debug. During several trials, sometimes I need to STOP running applications via Eclipse (probably through some interrupt signal). Whenever the application is interrupted, during the next run it cannot access the webcam and is returning "VIDIOC_STREAMON: Invalid argument" Apparently this is because resources are not released due to the interrupt. Also VLC cannot access webcam after I start seeing this error. Apparently there are 1-2 reports about this issue related to OpenCV and kernel, and there is also a workaround by handling SIGINT properly and correctly exiting. I could not work that solution in Eclipse, because probably Eclipse STOP button does not send SIGINT but some other signal. Nevertheless, I was expecting kernel to handle this in another way, so that resources would be released automatically to allow other applications to access webcam. However, webcam cannot be accessed after a program is interrupted. lsb_release -rd Description: Ubuntu 14.04.3 LTS Release: 14.04 uname -r 3.13.0-68-generic References: http://answers.opencv.org/question/28929/acquiring-video-from-webcam-problems/ http://askubuntu.com/questions/683327/libv4l2-error-turning-on-stream-invalid-argument-vidioc-streamon-invalid-argu https://lawlorcode.wordpress.com/2014/04/08/opencv-fix-for-v4l-vidioc_s_crop-error/ http://ubuntuforums.org/showthread.php?t=2298140 Please don't hesitate to ask for more information about the issue and correct me if my report isn't useful or sufficient. Update: After further testing, I realized Eclipse is sending SIGTERM signal, which if handled does not cause above mentioned issue. However, a program may still crash or terminated without handling it properly. This should not cause any issue for other applications. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l-utils/+bug/1518726/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp