Python functions to extract audio files from YouTube videos

youtube_music_download.py

"""
These functions allow you to create mp3 files from YouTube videos.  The scripts were created using Vibe coding.  
You can view the AI conversation at https://chatgpt.com/share/684995e4-aa14-800b-9ce5-f8c74cd34d9a.
Backup of conversation located at https://github.com/pmacMaps/pmacMaps.github.io/blob/ec99d84c3c3f88eb6bb1a8c93251f95ed38f2cde/assets/documents/Download_Audio_From_YouTube_ChatGPT_Chat_History.pdf

download_playlist_audio: extracts audio from all videos in a playlist 
download_audio: extracts audio from a single video
download_audio_segment: extracts audio from a single video using a start and end time stamp

Notes: you will need ffmpeg installed on the machine running this script.
You will also need to install the yt_dlp python module
"""

import yt_dlp as youtube_dl
from os import path

# extracts audio files (mp3) for all videos in the provided YouTube playlist
def download_playlist_audio(playlist_url, download_path='.', file_name_template=None):
    """
    playlist_url: string, YouTube playlist URL
    download_path: string, directory to save extracted audio files
    file_name_template: string, template for file names for extracted audio files
    """
    # handle file names for extracted files
    if file_name_template:
        outtmpl = path.join(download_path, file_name_template + '_%(playlist_index)s.%(ext)s')
    else:
        outtmpl = path.join(download_path, '%(title)s.%(ext)s')
    
    # Set the download options
    ydl_opts = {
        'format': 'bestaudio/best',
        'postprocessors': [{
            'key': 'FFmpegExtractAudio',
            'preferredcodec': 'mp3',
            'preferredquality': '192',
        }],
        'outtmpl': outtmpl,
        'yesplaylist': True,
        'ignoreerrors': True,
    }

    # extract audio from videos in playlist
    with youtube_dl.YoutubeDL(ydl_opts) as ydl:
        try:
            ydl.download([playlist_url])
        except Exception as e:
            print(f'error downloading song: {e}')
# end function to download from playlist

# extracts audio file (mp3) from the YouTube video provided
def download_audio(url, download_path='.', file_name=None):
    """
    url: string, YouTube video URL
    download_path: string, directory to save extracted audio file
    file_name: string, file name for extracted audio file
    """
    # If a custom file name is provided, set it as outtmpl
    if file_name:
        outtmpl = path.join(download_path, file_name + '.%(ext)s')
    else:
        outtmpl = path.join(download_path, '%(title)s.%(ext)s')

    # Set the download options
    ydl_opts = {
        'format': 'bestaudio/best',
        'postprocessors': [{
            'key': 'FFmpegExtractAudio',
            'preferredcodec': 'mp3',
            'preferredquality': '192',
        }],
        'outtmpl': outtmpl,
    }

    # extract audio from video
    with youtube_dl.YoutubeDL(ydl_opts) as ydl:
        try:
            ydl.download([url])
        except Exception as e:
            print(f'error downloading song: {e}')
# end function to download single song

# extracts audio file (mp3) from a segment of the YouTube video provided
def download_audio_segment(url, start_time, end_time, download_path='.', file_name=None):
    """
    url: string, YouTube video URL
    start_time: string, start segment of video to download (HH:MM:SS)
    end_time: string, end segment of video to download (HH:MM:SS)
    download_path: string, directory to save extracted audio file
    file_name: string, file name for extracted audio file
    """

    # Output filename
    if file_name:
        outtmpl = path.join(download_path, file_name + '.%(ext)s')
    else:
        outtmpl = path.join(download_path, '%(title)s.%(ext)s')

    # Construct ffmpeg arguments to trim audio
    ffmpeg_args = [
        '-ss', start_time,   # start time
        '-to', end_time      # end time
    ]

    # Set the download options
    ydl_opts = {
        'format': 'bestaudio/best',
        'outtmpl': outtmpl,
        'postprocessors': [{
            'key': 'FFmpegExtractAudio',
            'preferredcodec': 'mp3',
            'preferredquality': '192',
        }],
        'postprocessor_args': ffmpeg_args,
        'prefer_ffmpeg': True,
    }

     # extract audio from video
    with youtube_dl.YoutubeDL(ydl_opts) as ydl:
        try:
            ydl.download([url])
        except Exception as e:
            print(f'error downloading song: {e}')
# end function to download audio from provided start and end time segments