Python Video Converter Using OpenCV: Convert Videos to Grayscale, Black‑White, and RGB

Video converters allow users to change a video from one format to another; this guide demonstrates how to implement such a tool in Python 3 using the OpenCV4 library.

Project description : The converter reads a video file, optionally converts each frame to grayscale, black‑and‑white, or RGB, and saves the processed frames as a new video file.

Project code :

import cv2
import argparse

def convert_video(input_file, output_file, output_codec, gray=False, bw=False):
    # read the original video
    cap = cv2.VideoCapture(input_file)
    # set codec and get the size of frames
    fourcc = cv2.VideoWriter_fourcc(*output_codec)
    width = int(cap.get(3))
    height = int(cap.get(4))
    # create the output video writer
    out = cv2.VideoWriter(output_file, fourcc, 30, (width, height), True)
    while (cap.isOpened()):
        # read the frame
        ret, frame = cap.read()
        # check if end of the video
        if not ret:
            break
        # convert to gray
        if gray:
            frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
        # convert to black and white
        if bw:
            _, frame = cv2.threshold(frame, 127, 255, cv2.THRESH_BINARY)
        # convert to RGB
        if not gray and not bw:
            frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
        # write the frame to output video
        out.write(frame)
        # display the frame
        cv2.imshow('frame', frame)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break
    # release the video capture and writer
    cap.release()
    out.release()
    # close all windows
    cv2.destroyAllWindows()

Project dependencies : Install OpenCV with pip install opencv-python .

The conversion process reads the original video, sets the codec, obtains frame dimensions, creates a writer, processes each frame according to the selected mode, writes the processed frame, and finally releases resources.

Argument parsing (optional):

ap = argparse.ArgumentParser()
ap.add_argument("-i", "--input", required=True, help="path to input video")
ap.add_argument("-o", "--output", required=True, help="path to output video")
ap.add_argument("-c", "--codec", required=True, help="codec of output video")
ap.add_argument("-g", "--gray", action="store_true", help="convert video to gray")
ap.add_argument("-b", "--bw", action="store_true", help="convert video to black-and-white")
args = vars(ap.parse_args())
convert_video(args["input"], args["output"], args["codec"], args["gray"], args["bw"])

Key parameters:

--input and --output specify the input and output video file paths.

--codec defines the codec name for the output video (e.g., "H.264").

These arguments enable running the script directly from the command line, controlling the conversion mode.

Project summary : The video format converter is a useful utility that simplifies changing video files between formats; using Python 3 and OpenCV makes implementation straightforward and saves time when handling video format conversions.