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In this guide, we’ll show you how to transcribe YouTube videos. For this, we use the yt-dlp library to download YouTube videos and then transcribe it with the AssemblyAI API. yt-dlp is a youtube-dl fork with additional features and fixes. It is better maintained and preferred over youtube-dl nowadays. In this guide we’ll show 2 different approaches:
  • Option 1: Download video via CLI
  • Option 2: Download video via code
Let’s get started!

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Quickstart

import assemblyai as aai
import yt_dlp

def transcribe_youtube_video(video_url: str, api_key: str) -> str:
    """
    Transcribe a YouTube video given its URL.

    Args:
        video_url: The YouTube video URL to transcribe
        api_key: AssemblyAI API key

    Returns:
        The transcript text
    """
    # Configure yt-dlp options for audio extraction
    ydl_opts = {
        'format': 'm4a/bestaudio/best',
        'outtmpl': '%(id)s.%(ext)s',
        'postprocessors': [{
            'key': 'FFmpegExtractAudio',
            'preferredcodec': 'm4a',
        }]
    }

    # Download and extract audio
    with yt_dlp.YoutubeDL(ydl_opts) as ydl:
        ydl.download([video_url])
        # Get video ID from info dict
        info = ydl.extract_info(video_url, download=False)
        video_id = info['id']

    # Configure AssemblyAI
    aai.settings.api_key = api_key

    # Transcribe the downloaded audio file
    config = aai.TranscriptionConfig(speech_models=["universal-3-pro", "universal-2"])
    transcriber = aai.Transcriber()
    transcript = transcriber.transcribe(f"{video_id}.m4a", config)

    return transcript.text

transcript_text = transcribe_youtube_video("https://www.youtube.com/watch?v=wtolixa9XTg", "YOUR-API-KEY")
print(transcript_text)

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Step-by-step guide

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Install Dependencies

Install yt-dlp and the AssemblyAI Python SDK via pip. 
pip install -U yt-dlp

pip install assemblyai

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Option 1: Download video via CLI

In this approach we download the YouTube video via the command line and then transcribe it via the AssemblyAI API. We use the following video here: To download it, use the yt-dlp command with the following options:
  • -f m4a/bestaudio: The format should be the best audio version in m4a format.
  • -o "%(id)s.%(ext)s": The output name should be the id followed by the extension. In this example, the video gets saved to “wtolixa9XTg.m4a”.
  • wtolixa9XTg: the id of the video.
yt-dlp -f m4a/bestaudio -o "%(id)s.%(ext)s" https://www.youtube.com/watch?v=wtolixa9XTg
Next, set up the AssemblyAI SDK and trancribe the file. Replace YOUR_API_KEY with your own key. If you don’t have one, you can sign up here for free. Make sure that the path you pass to the transcribe() function corresponds to the saved filename. 
import assemblyai as aai

aai.settings.api_key = "YOUR_API_KEY"

config = aai.TranscriptionConfig(speech_models=["universal-3-pro", "universal-2"])
transcriber = aai.Transcriber()
transcript = transcriber.transcribe("wtolixa9XTg.m4a", config)
print(transcript.text)

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Option 2: Download video via code

In this approach we download the video with a Python script instead of the command line. You can download the file with the following code: 
import yt_dlp

URLS = ['https://www.youtube.com/watch?v=wtolixa9XTg']

ydl_opts = {
    'format': 'm4a/bestaudio/best',  # The best audio version in m4a format
    'outtmpl': '%(id)s.%(ext)s',  # The output name should be the id followed by the extension
    'postprocessors': [{  # Extract audio using ffmpeg
        'key': 'FFmpegExtractAudio',
        'preferredcodec': 'm4a',
    }]
}


with yt_dlp.YoutubeDL(ydl_opts) as ydl:
    error_code = ydl.download(URLS)
After downloading, you can use the same code from option 1 to transcribe the file: 
import assemblyai as aai

aai.settings.api_key = "YOUR_API_KEY"

config = aai.TranscriptionConfig(speech_models=["universal-3-pro", "universal-2"])
transcriber = aai.Transcriber()
transcript = transcriber.transcribe("wtolixa9XTg.m4a", config)