Python | Play a video using OpenCV

OpenCV (Open Source Computer Vision) is a powerful computer-vision library used for working with images and videos. One of its common uses is playing video files inside a Python window. To do this, we use the VideoCapture class, which allows OpenCV to open and read videos frame by frame.

We will be using this sample video for demonstration. To download it, click here.

When working with videos, OpenCV reads each frame sequentially in a loop, displaying them just like a regular media player.

Module Installation

We are going to use cv2 library for this project, install it using the folowing pip command:

pip install cv2

 Syntax

• cv2.VideoCapture(0) → Opens the default webcam
• cv2.VideoCapture(1) → Opens the second webcam
• cv2.VideoCapture("file.mp4") → Loads a video file

Step-by-Step Process

Step 1: Import the required modules,

import cv2

Step 2: Load the video file

cap = cv2.VideoCapture(cap = cv2.VideoCapture("video.mp4")

Step 3: Check if the video was loaded successfully

if not cap.isOpened():
    print("Error: Could not open video file.")
    exit()

Step 4: Read and display video frame-by-frame

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

    if not ret:
        break   # No more frames → end of video

    cv2.imshow("Video", frame)

    # Press Q to quit
    if cv2.waitKey(25) & 0xFF == ord('q'):
        break

Step 5: Release and close

cap.release()
cv2.destroyAllWindows()

Complete Working Code

import cv2

# Load the video file
cap = cv2.VideoCapture("video.mp4")

# Check if the video opened correctly
if not cap.isOpened():
    print("Error: Could not open video file.")
    exit()

# Read and display video frames
while True:
    ret, frame = cap.read()

    if not ret:
        break   # No more frames -> exit loop

    cv2.imshow("Video", frame)

    # Press Q to quit
    if cv2.waitKey(25) & 0xFF == ord('q'):
        break

# Release resources
cap.release()
cv2.destroyAllWindows()

Output

Note : Video file should have in same directory where program is executed.

Explanation:

• VideoCapture() loads the video.
• cap.read() fetches each frame.
• imshow() displays the frame.
• waitKey(25) adds a small delay between frames to create a video effect.
• Pressing Q exits the loop.
• After the video ends, OpenCV releases the video and closes all windows.