Ubuntu.my.id

OpenCv error can't open camera through video capture

Posted on Apr 28, 2023

Question

I was using my cam through opencv and suddenly after restarting I ran my code it shows below error:

[ WARN:0] global /io/opencv/modules/videoio/src/cap_v4l.cpp (802) open VIDEOIO ERROR: V4L: can't open camera by index 0
Traceback (most recent call last):
  File "test.py", line 20, in <module>
    retval, buffer_img = cv2.imencode('.jpg', frame)
cv2.error: OpenCV(4.1.2) /io/opencv/modules/imgcodecs/src/loadsave.cpp:877: error: (-215:Assertion failed) !image.empty() in function 'imencode'

cap = cv2.VideoCapture(0)  # here it throws an error

import json
while(True):
# Capture frame-by-frame
ret, frame = cap.read()


retval, buffer_img = cv2.imencode('.jpg', frame)

resdata = base64.b64encode(buffer_img)

resdata = "data:image/png;base64,"+ str(resdata.decode("utf-8"))
PARAMS = {'image': resdata}

# Our operations on the frame come here
#gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

# Display the resulting frame
cv2.imshow('frame',frame)
if cv2.waitKey(1) &amp; 0xFF == ord('q'):
    break

When everything done, release the capture
cap.release()
cv2.destroyAllWindows()

I also tried with cap = cv2.VideoCapture(1) but then it shows can't find camera

How can I fix this issue?

Answer

I got the same error. Try changing 0 to -1

cap = cv2.VideoCapture(-1)

This solved the issue.