我正在使用树莓派来捕获视频的前 20 帧。现在这更多的是一个概念问题，但是在浏览有关 videoCapture 的 openCV 文档时，他们强调了在此代码中释放捕获的重要性（如其网站上发布的）：
import numpy as np
import cv2
cap = cv2.VideoCapture(0)
while(True):
# Capture frame-by-frame
ret, frame = cap.read()
# Our operations on the frame come here
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
# Display the resulting frame
cv2.imshow('frame',gray)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()
有何重要性cap.release()？省略这一行是否有任何记忆含义？如果是的话，它们是什么以及为什么？
你打电话时cap.release(), then:
- 释放软件资源
- 释放硬件资源
您可以尝试创建另一个实例cap2 = cv2.VideoCapture(0)在你打电话之前cap.release().
cap = cv2.VideoCapture(0)
#cap.release()
cap2 = cv2.VideoCapture(0)
因为你还没有释放相机设备资源，那么它会引发类似的错误Device or resource busy，导致引发 OpenCV 异常。
libv4l2: error setting pixformat: Device or resource busy
VIDEOIO ERROR: libv4l unable to ioctl S_FMT
libv4l2: error setting pixformat: Device or resource busy
libv4l1: error setting pixformat: Device or resource busy
VIDEOIO ERROR: libv4l unable to ioctl VIDIOCSPICT
libv4l2: error setting pixformat: Device or resource busy
OpenCV Error: Unspecified error (GStreamer: unable to start pipeline
) in cvCaptureFromCAM_GStreamer, file /home/xxx/Programs/OpenCV/src/opencv-master/modules/videoio/src/cap_gstreamer.cpp, line 887
VIDEOIO(cvCreateCapture_GStreamer(CV_CAP_GSTREAMER_V4L2, reinterpret_cast<char *>(index))): raised OpenCV exception:
/home/xxx/Programs/OpenCV/src/opencv-master/modules/videoio/src/cap_gstreamer.cpp:887: error: (-2) GStreamer: unable to start pipeline
in function cvCaptureFromCAM_GStreamer
本文内容由网友自发贡献，版权归原作者所有，本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容，请联系:hwhale#tublm.com(使用前将#替换为@)
