FileNotFoundError: [WinError 2] The system cannot find the file specified when using moviepy

Question

I am trying to reduce the file size of a .mp4 file using the following code:

import os
import moviepy.editor as mp
import ffmpeg

def compress_video(input_file, output_file, target_size_ratio=0.5):
    if not os.path.exists(input_file):
        raise FileNotFoundError(f"Input file not found: {input_file}")

    if target_size_ratio <= 0 or target_size_ratio >= 1:
        raise ValueError("Target size ratio must be between 0 and 1")

    # Get input video information
    probe = ffmpeg.probe(input_file)
    video_stream = next((stream for stream in probe['streams'] if stream['codec_type'] == 'video'), None)
    bitrate = int(video_stream['bit_rate'])

    # Calculate new bitrate to achieve the target file size
    new_bitrate = int(bitrate * target_size_ratio)

    # Load the video and compress
    input_video = mp.VideoFileClip(input_file)
    input_video.write_videofile(
        output_file,
        bitrate=f"{new_bitrate}k",
        codec="libx264",
        audio_codec="aac",
        threads=4,
        ffmpeg_params=["-strict", "-2"]
    )

input_file = r"C:\Users\Hamid\Downloads\A.mp4"
output_file = r"C:\Users\Hamid\Downloads\B.mp4"
compress_video(input_file, output_file, target_size_ratio=0.5)

But I am getting the following error:

FileNotFoundError: [WinError 2] The system cannot find the file specified

Just a note I have a file in that directory called A.mp4 but currently no file exists called B.mp4.