CODEWITHSUNDEEP
pythonopencv
parvaneh
parvaneh

Reputation: 530

TypeError: Required argument 'mat' (pos 2) not found

I have the code below with cv2 . This code is downloaded from https://github.com/dipakkr/3d-cnn-action-recognition. I want to use cv2.imshow to visualize the frames of the video it get. But I get the following error. What is the problem? I am doubtful of whether this code is really able to read the video as what is returns as the output is an array of zeros. 

def video3d(self, filename, color=False, skip=True):

        cap = cv2.VideoCapture(filename)
        #ret, frame=cap.read()
        #cv2.imshow('frame', frame)
        nframe = cap.get(cv2.CAP_PROP_FRAME_COUNT) #Returns the specified VideoCapture property  ,,Number of frames in the video file

        print (nframe, "nframe")

        if skip:
            frames = [x * nframe / self.depth for x in range(self.depth)]
            print (frames, "frameeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees")

        else:
            frames = [x for x in range(self.depth)]
            print (frames, "frameseeeeeeeeeeeeeeeeeeeeeeeeeeeeeee2")

        framearray = []

        for i in range(self.depth):
            cap.set(cv2.CAP_PROP_POS_FRAMES, frames[i])  #Sets a property in the VideoCapture. ,,0-based index of the frame to be decoded/captured next.
            ret, frame = cap.read()
            cv2.imshow(frame)
            print(ret, "reeeeeeeeeeeeeeeeettttttttt")
            print(frame ,"frame issssssssssss:")
            frame = cv2.resize(frame, (self.height, self.width))
            print(frame, "frame222 isssssssssssssss")
            #cv2.imshow(frame)
            if color:
                framearray.append(frame)
            else:
                framearray.append(cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY))

        cap.release()
        return np.array(framearray)


X.append(vid3d.video3d(v_file_path, color=color, skip=skip))

Error:

    main()
  File "3dcnn.py", line 151, in main
    args.output, args.color, args.skip)
  File "3dcnn.py", line 103, in loaddata
    X.append(vid3d.video3d(v_file_path, color=color, skip=skip))
  File "/home/gxa131/Documents/final_project_computationalintelligence/3d-cnn-action-recognition/videoto3d.py", line 34, in video3d
    cv2.imshow(frame)
TypeError: Required argument 'mat' (pos 2) not found

Upvotes: 18

Views: 97095

Answers (5)

Felipe Brandao
Felipe Brandao

Reputation: 1

Another suggestion is to use plt.imshow() instead of cv2_imshow or cv2.imshow:

from matplotlib import pyplot as plt

    def display_frame_in_notebook(frame):
    
        # Convert the image from BGR to RGB (since OpenCV loads images 
        in BGR format)
    
        frame_rgb = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
        plt.imshow(frame_rgb)
        plt.axis('off')  # Hide the axis
        plt.show()

Then you should be able to change from:

cv2.imshow('frame', frame) or cv2_imshow(frame)

to:

display_frame_in_notebook(frame).

Upvotes: -1

Gimantha23
Gimantha23

Reputation: 367

I had the same problem, Solved by giving the full path of the image to imread()

Upvotes: 0

Nicolas Gervais
Nicolas Gervais

Reputation: 36624

cv2 didn't the find the "mat" (matrix), because you passed the image as the first argument, but the first argument is supposed to be the window name.

cv2.imshow(winname, mat)

In most cases, you don't care about the window name, so use this:

cv2.imshow('', frame)
cv2.waitKey(0)

This is the result when you change the window name:

import numpy as np
import cv2

image = np.full((300, 300, 3), 255).astype(np.uint8)

cv2.putText(image, 'some picture', (20, 60),
            cv2.FONT_HERSHEY_SIMPLEX, 1, [0, 0, 0])

cv2.imshow('custom window name', image)
cv2.waitKey(0)

enter image description here

One of the reasons you might want to change window names is to plot many pictures at once, in different windows.

Upvotes: 9

Shilpa
Shilpa

Reputation: 164

I know that this question is already answered but would like to add a generic ans to it!

Basically python through this error, when we miss to provide the 2nd parameter to the called function.

When such a error comes just go to the line number pointed in error at output section and check that the function you have called, have all the parameter passed.

Upvotes: 0

A Kruger
A Kruger

Reputation: 2419

The first argument to cv2.imshow is the window name, so it's considering the second input mat (the image) as missing. If you don't want to name the window, you can just give an empty string as the first input parameter.

cv2.imshow('', frame)

Upvotes: 26

Related Questions