Reading video with OpenCV in Computer Vision - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to open a video file using OpenCV.

Computer Vision

import cv2

cap = cv2.VideoCapture([1])

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A"video.mp4"

Bvideo.mp4

C123

DTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the filename

Passing a variable name without quotes

The VideoCapture function expects a string path to the video file, so the filename must be in quotes.

2fill in blank

medium

Complete the code to read a frame from the video capture object.

Computer Vision

ret, frame = cap.[1]()

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Afetch

Bcapture

Cget

Dread

Attempts:

3 left

💡 Hint

Common Mistakes

Using cap.get() which retrieves properties, not frames

Using incorrect method names like capture() or fetch()

The read() method reads the next frame from the video capture object.

3fill in blank

hard

Fix the error in the loop condition to properly check if the frame was read.

Computer Vision

while cap.isOpened():
    ret, frame = cap.read()
    if not [1]:
        break

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Aret

Bframe

Ccap

DTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Checking 'if not frame:' which can cause errors

Using 'if not cap:' which is incorrect

The variable 'ret' is a boolean indicating if the frame was read successfully.

4fill in blank

hard

Fill both blanks to convert the frame to grayscale and display it.

Computer Vision

gray = cv2.[1](frame, cv2.[2])
cv2.imshow('Gray Frame', gray)

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AcvtColor

BCOLOR_BGR2GRAY

CCOLOR_RGB2GRAY

Dresize

Attempts:

3 left

💡 Hint

Common Mistakes

Using resize instead of cvtColor

Using COLOR_RGB2GRAY when frames are in BGR format

Use cvtColor to convert color spaces and COLOR_BGR2GRAY to convert BGR to grayscale.

5fill in blank

hard

Fill all three blanks to release the video and close all OpenCV windows.

Computer Vision

cap.[1]()
cv2.[2]()
cv2.[3](0)

Drag options to blanks, or click blank then click option'

Arelease

BdestroyAllWindows

CwaitKey

Dimshow

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to release the video capture

Not closing windows properly

Using imshow instead of waitKey

release() frees the video resource, destroyAllWindows() closes windows, and waitKey() waits for a key press.