CODEWITHSUNDEEP
pythonopencvvideo-capture
Omkar Mane
Omkar Mane

Reputation: 9

I got Error while creating face recognition code. The Error is " TypeError: Expected Ptr<cv::UMat> for argument 'src' " what is solution

import cv2
video=cv2.VideoCapture(0)
img=video.read()
video2=cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
cv2.imshow("camera",video2)
cv2.waitKey(0)

"HERE IS THE ERROR" """ Traceback (most recent call last): File "C:/Users/D_Ommy/PycharmProjects/Machine_Learning/sampleone.py", line 4, in video2=cv2.cvtColor(img, cv2.COLOR_BGR2RGB) TypeError: Expected Ptr<cv::UMat> for argument 'src' [ WARN:0] global C:\Users\appveyor\AppData\Local\Temp\1\pip-req-build-cff9bdsm\opencv\modules\videoio\src\cap_msmf.cpp (435) `anonymous-namespace'::SourceReaderCB::~SourceReaderCB terminating async callback

"""

Upvotes: 0

Views: 4386

Answers (2)

Ask the right questions
Ask the right questions

Reputation: 53

Add this parameter "cv2.CAP_DSHOW" to the second line of your code :

import cv2
video=cv2.VideoCapture(0, cv2.CAP_DSHOW)
img=video.read()
video2=cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
cv2.imshow("camera",video2)
cv2.waitKey(0)

Upvotes: 0

Muhammad Usman
Muhammad Usman

Reputation: 29

For this let's go each and every step and what the code is doing.

cv2.VideoCapture(0)

The VideoCapture() on OpenCV returns an object that can be used to capture video frame-by-frame (this is not the actual video). Once this object is created, the next step as rightly done should be to read the frames.

img=video.read()

This OBJECT.read() method returns TWO values instead of one, a boolean flag and the frame. This is what missing here. The correct code for this kind of work could be something as follows.

import cv2

cap = cv2.VideoCapture('vtest.avi')

while(cap.isOpened()):
    ret, frame = cap.read()

    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()

For details, it's always better to consult the official documentation with code examples. https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_gui/py_video_display/py_video_display.html

Upvotes: 0

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