Saving Operated Video from a webcam in OpenCV

Saving a video from a webcam involves capturing frames from the webcam and then writing them to a video file. Here's a step-by-step tutorial on how to achieve this using OpenCV:

1. Setup:

Make sure you've installed OpenCV:

pip install opencv-python

Then, import the necessary libraries:

import cv2

2. Initialize the Webcam:

Use cv2.VideoCapture() to capture video from the webcam:

cap = cv2.VideoCapture(0)  # 0 is the default camera. Change the index if you have multiple cameras.

3. Define the Video Writer:

Before saving the video, you need to define the video writer and specify details like codec, frame rate, and resolution:

# Define the codec using VideoWriter_fourcc(*'XVID') and create VideoWriter object
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('output.avi', fourcc, 20.0, (int(cap.get(3)), int(cap.get(4))))

Here:

'XVID' is a codec used to compress and decompress video files, you can also use 'MP4V' or 'MJPG'.
'output.avi' is the name of the output video file.
20.0 is the frames per second.
(int(cap.get(3)), int(cap.get(4))) gets the width and height of the frames, respectively.

4. Capture and Save the Video:

Now, you'll read frames from the webcam in a loop, possibly perform some operations on the frames, and then write them to the video file:

while cap.isOpened():
    ret, frame = cap.read()  # Read a frame
    if ret:
        # You can perform operations on 'frame' here if desired

        out.write(frame)  # Save the frame to the video file

        cv2.imshow('Frame', frame)  # Show the frame
        if cv2.waitKey(1) & 0xFF == ord('q'):  # Exit when 'q' key is pressed
            break
    else:
        break

5. Cleanup:

Always release the video capture and writer objects and close all OpenCV windows:

cap.release()
out.release()
cv2.destroyAllWindows()

Complete Code:

Here's the full script to capture video from the webcam and save it:

import cv2

# Initialize the webcam
cap = cv2.VideoCapture(0)

# Define the codec and create VideoWriter object
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('output.avi', fourcc, 20.0, (int(cap.get(3)), int(cap.get(4))))

while cap.isOpened():
    ret, frame = cap.read()
    if ret:
        # Perform operations on the frame if needed

        out.write(frame)
        cv2.imshow('Frame', frame)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break
    else:
        break

# Cleanup
cap.release()
out.release()
cv2.destroyAllWindows()

Run the script and you'll capture video from your webcam. Press 'q' to stop recording. You should find the recorded video named 'output.avi' in the directory where the script was executed.

Saving processed video from a webcam with OpenCV in Python:

import cv2

# Open a connection to the webcam (0 represents the default camera)
cap = cv2.VideoCapture(0)

# Get the default width and height of the frames
frame_width = int(cap.get(3))
frame_height = int(cap.get(4))

# Define the codec and create a VideoWriter object
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('output_video.avi', fourcc, 20.0, (frame_width, frame_height))

while True:
    # Read a frame from the webcam
    ret, frame = cap.read()

    # Perform processing on the frame (e.g., convert to grayscale)
    gray_frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    # Display the processed frame
    cv2.imshow('Processed Frame', gray_frame)

    # Write the processed frame to the output video file
    out.write(gray_frame)

    # Break the loop if 'q' is pressed
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# Release the VideoCapture and VideoWriter objects
cap.release()
out.release()

# Close all OpenCV windows
cv2.destroyAllWindows()

Python code for saving video from a webcam in OpenCV:

import cv2

# Open a connection to the webcam (0 represents the default camera)
cap = cv2.VideoCapture(0)

# Get the default width and height of the frames
frame_width = int(cap.get(3))
frame_height = int(cap.get(4))

# Define the codec and create a VideoWriter object
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('output_video.avi', fourcc, 20.0, (frame_width, frame_height))

while True:
    # Read a frame from the webcam
    ret, frame = cap.read()

    # Display the frame
    cv2.imshow('Webcam Frame', frame)

    # Write the frame to the output video file
    out.write(frame)

    # Break the loop if 'q' is pressed
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# Release the VideoCapture and VideoWriter objects
cap.release()
out.release()

# Close all OpenCV windows
cv2.destroyAllWindows()

Video capture and processing with OpenCV:

import cv2

# Open a connection to the webcam (0 represents the default camera)
cap = cv2.VideoCapture(0)

while True:
    # Read a frame from the webcam
    ret, frame = cap.read()

    # Perform processing on the frame (e.g., convert to grayscale)
    gray_frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    # Display the processed frame
    cv2.imshow('Processed Frame', gray_frame)

    # Break the loop if 'q' is pressed
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# Release the VideoCapture object
cap.release()

# Close all OpenCV windows
cv2.destroyAllWindows()

Real-time video processing and saving in OpenCV:

import cv2

# Open a connection to the webcam (0 represents the default camera)
cap = cv2.VideoCapture(0)

# Get the default width and height of the frames
frame_width = int(cap.get(3))
frame_height = int(cap.get(4))

# Define the codec and create a VideoWriter object
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('output_video.avi', fourcc, 20.0, (frame_width, frame_height))

while True:
    # Read a frame from the webcam
    ret, frame = cap.read()

    # Perform processing on the frame (e.g., convert to grayscale)
    gray_frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    # Display the processed frame
    cv2.imshow('Processed Frame', gray_frame)

    # Write the processed frame to the output video file
    out.write(gray_frame)

    # Break the loop if 'q' is pressed
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# Release the VideoCapture and VideoWriter objects
cap.release()
out.release()

# Close all OpenCV windows
cv2.destroyAllWindows()

Saving video frames with specified file names in OpenCV:

import cv2

# Open a connection to the webcam (0 represents the default camera)
cap = cv2.VideoCapture(0)

frame_number = 0

while True:
    # Read a frame from the webcam
    ret, frame = cap.read()

    # Save each frame with a specified file name
    frame_file_name = f'frame_{frame_number}.jpg'
    cv2.imwrite(frame_file_name, frame)

    # Increment the frame number
    frame_number += 1

    # Display the frame
    cv2.imshow('Webcam Frame', frame)

    # Break the loop if 'q' is pressed
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# Release the VideoCapture object
cap.release()

# Close all OpenCV windows
cv2.destroyAllWindows()

Combining video capture, processing, and saving with other OpenCV functions:

import cv2

# Open a connection to the webcam (0 represents the default camera)
cap = cv2.VideoCapture(0)

# Get the default width and height of the frames
frame_width = int(cap.get(3))
frame_height = int(cap.get(4))

# Define the codec and create a VideoWriter object
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('output_video.avi', fourcc, 20.0, (frame_width, frame_height))

while True:
    # Read a frame from the webcam
    ret, frame = cap.read()

    # Perform processing on the frame (e.g., convert to grayscale)
    gray_frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    # Apply additional processing as needed
    # ...

    # Display the processed frame
    cv2.imshow('Processed Frame', gray_frame)

    # Write the processed frame to the output video file
    out.write(gray_frame)

    # Break the loop if 'q' is pressed
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# Release the VideoCapture and VideoWriter objects
cap.release()
out.release()

# Close all OpenCV windows
cv2.destroyAllWindows()