Good day to you dear developers from stackoverflow. I am currently recording live-video with my usb webcam on my raspberry Pi with the following code:
import cv2 as cv
import time
class CameraInst():
# Constructor...
def __init__(self):
cap = cv.VideoCapture(0) # Capture Video...
cap.set(cv.CAP_PROP_FOURCC, cv.VideoWriter_fourcc('M','J','P','G'))
cap.set(cv.CAP_PROP_FPS, 15)
cap.set(cv.CAP_PROP_FRAME_WIDTH, 1920)
cap.set(cv.CAP_PROP_FRAME_HEIGHT, 1080)
self.cap=cap
print("Aufnahme wird vorbereitet")
time.sleep(1)
def captureVideo(self):
# Capture
ret, self.frame = self.cap.read()
cv.moveWindow('frame',0,0)
cv.imshow('frame',self.frame)
def main():
cam1 = CameraInst()
while(True):
# Display the resulting frames...
cam1.captureVideo() # Live stream of video on screen...
if cv.waitKey(1) & 0xFF == ord('q'):
break
if __name__=='__main__':
main()
The code doesn't work anymore, when I use the cap.set(cv.CAP_PROP_FPS, 15) function and I don't know what I've done wrong.
I get the following errors:
[ WARN:0] global ../modules/videoio/src/cap_gstreamer.cpp (961) open OpenCV | GStreamer warning: Cannot query video position: status=0, value=-1, duration=-1
[ WARN:0] global ../modules/videoio/src/cap_gstreamer.cpp (1214) setProperty OpenCV | GStreamer warning: GStreamer: unhandled property
[ WARN:0] global ../modules/videoio/src/cap_gstreamer.cpp (1824) handleMessage OpenCV | GStreamer warning: Embedded video playback halted; module v4l2src0 reported: Internal data stream error.
[ WARN:0] global ../modules/videoio/src/cap_gstreamer.cpp (536) startPipeline OpenCV | GStreamer warning: unable to start pipeline
[ WARN:0] global ../modules/videoio/src/cap_gstreamer.cpp (1085) setProperty OpenCV | GStreamer warning: no pipeline
[ WARN:0] global ../modules/videoio/src/cap_gstreamer.cpp (1085) setProperty OpenCV | GStreamer warning: no pipeline
Aufnahme wird vorbereitet
Traceback (most recent call last):
File "/home/pi/Documents/RPV_Video_V8.py", line 45, in <module>
main()
File "/home/pi/Documents/RPV_Video_V8.py", line 40, in main
cam1.captureVideo() # Live stream of video on screen...
File "/home/pi/Documents/RPV_Video_V8.py", line 31, in captureVideo
cv.imshow('frame',self.frame)
cv2.error: OpenCV(4.5.1) ../modules/highgui/src/window.cpp:376: error: (-215:Assertion failed) size.width>0 && size.height>0 in function 'imshow'
Not the thing is, if I remove the cap.set(cv.CAP_PROP_FPS, 15) then the code works fine, but then the camera record with YUYV and not MJPG.
CodePudding user response:
Set the CAP_PROP_FOURCC
property to MJPG
.
Look at VideoWriter (yes) documentation for details on handling fourcc values.
cap.set(cv.CAP_PROP_FOURCC, cv.VideoWriter_fourcc(*"MJPG"))
Order of .set()
method calls matters. Try to put this first. And perhaps also set CAP_PROP_FPS
to be sure.