In this Python OpenCV article we are going to learn Reading Mp4 Video Formats, so first of all let’s talk about Python OpenCV.
What is Python OpenCV ?
OpenCV (Open Source Computer Vision Library) is free and open source computer vision and machine learning software library for Python. it is designed to help developers create computer vision applications by providing different functions for image and video processing, including:
- Image and video processing: OpenCV provides tools for reading, writing and manipulating images and video files including functions for image filtering, color space conversion, image morphology and feature detection.
- Object detection and recognition: OpenCV includes different tools for detecting and recognizing objects in images and video, including face detection, pedestrian detection and object tracking.
- Machine learning: OpenCV provides alot of machine learning algorithms, including support vector machines (SVMs), decision trees and neural networks that can be used for image classification, object recognition, and other tasks.
- Camera calibration and 3D reconstruction: OpenCV includes functions for camera calibration, stereo vision, and 3D reconstruction, which can be used to build 3D models from images and video.
- User interface: OpenCV provides tools for creating graphical user interfaces (GUIs) that can be used to display images and video and interact with users.
Python OpenCV Installation
You can install Python OpenCV using pip command like this
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pip install opencv-python |
Python OpenCV Reading Mp4 Video Formats
In OpenCV we can Read video either by using the feed from a camera connected to a computer or by reading a video file. The first step towards reading a video file is to create a VideoCapture object. Its argument can be either the device index or the name of the video file to be read.
In most cases, only one camera is connected to the system. So, all we do is pass ‘0’ and OpenCV uses the only camera attached to the computer. When more than one camera is connected to the computer, we can select the second camera by passing ‘1’, the third camera by passing ‘2’ and so on.
This is the complete source code for this article, make sure that you have added an mp4 video format in your working directory.
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import cv2 # Create a VideoCapture object and read from input file # If the input is the camera, pass 0 instead of the video file name cap = cv2.VideoCapture('vid2.mp4') # Check if camera opened successfully if (cap.isOpened()== False): print("Error opening video stream or file") # Read until video is completed while (cap.isOpened()): # Capture frame-by-frame ret, frame = cap.read() if ret == True: # Display the resulting frame cv2.imshow('Frame', frame) # Press Q on keyboard to exit if cv2.waitKey(25) & 0xFF == ord('q'): break # Break the loop else: break # When everything done, release the video capture object cap.release() # Closes all the frames cv2.destroyAllWindows() |
So let me describe the code at the top we have imported OpenCV after that in the first line of the code we have created a VideoCapture object and we are reading the video from input file and after that we checking if the camera is opened successfully you can do this by if (cap.isOpened()== False): after we create a while loop because we want to read the video until the completion of the video and in the loop we capture the video frame by frame by using ret,frame = cap.read() and after we show the frame by using cv2.imshow().
at the end when everything is done we need to release the video capture by using cap.release()
You can download the sample video from below link
Sample Video For OpenCV Video Reading
If you run the complete code you will have your mp4 video playing in OpenCV window.
FAQs:
How to read an image with OpenCV-Python?
For reading an image with OpenCV-Python, you can use cv2.imread() function. This function takes the path of the image file as input and returns a NumPy array, and it represents the image. This is an example:
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import cv2 # Read an image from file image = cv2.imread('image.jpg') |
How to display an image using OpenCV-Python?
For displaying an image using OpenCV-Python, you can use cv2.imshow() function. This function displays an image in a window. After that you can use cv2.waitKey() to wait for a key press and cv2.destroyAllWindows() to close all OpenCV windows. This is an example:
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import cv2 # Read an image from file image = cv2.imread('lena.tif') # Display the image in a window titled 'MyImage' cv2.imshow('MyImage', image) # Wait indefinitely for a key press cv2.waitKey(0) # Close all OpenCV windows cv2.destroyAllWindows() |
How to read an mp4 file using cv2?
For reading an mp4 file using cv2 (OpenCV), you can use cv2.VideoCapture() function. This function initializes a video capture object that can be used to read frames from the specific video file. You just need to provide the file path or URL of the mp4 file as an argument. This is an example:
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import cv2 # Initialize video capture object for mp4 file cap = cv2.VideoCapture('video.mp4') # Read frames from the mp4 file while cap.isOpened(): ret, frame = cap.read() if ret: # Process the frame # ... else: break # Release the video capture object cap.release() |
How to open an mp4 file in Python OpenCV?
For opening an mp4 file with OpenCV you can use cv2.VideoCapture() function from the OpenCV library. This function initializes a video capture object that allows you to read frames from the mp4 file. Simply provide the file path or URL of the mp4 file as an argument. This is an example:
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import cv2 # Initialize video capture object for mp4 file cap = cv2.VideoCapture('video.mp4') |
How to use cv2 VideoCapture?
For using cv2 VideoCapture, first you need to initialize a video capture object using cv2.VideoCapture() function. This object allows you to capture frames from a video file or webcam. After that you can use use the read() method of the video capture object to capture a frame.
How to save an mp4 video in OpenCV?
For saving an mp4 video in OpenCV, you can use cv2.VideoWriter() function. This function initializes a video writer object that can be used to write frames to an mp4 file. You need to provide the file name of the output mp4 file, the FourCC code specifying the codec to be used, the frame rate (FPS), and the frame size as arguments.
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