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The YouTube Downloader component handles downloading videos from YouTube URLs with interactive resolution selection and automatic video/audio merging for adaptive streams.

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Functions

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download_youtube_video

Downloads a YouTube video with interactive quality selection and automatic handling of progressive and adaptive streams. 
download_youtube_video(url: str) -> str
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url
str
required
The YouTube video URL to download
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output_file
str
Path to the downloaded video file in the videos/ directory

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Features

  • Interactive Resolution Selection: Shows top 5 available resolutions with sizes
  • Auto-Selection: 5-second timeout automatically selects highest quality
  • Adaptive Stream Handling: Automatically merges separate video/audio streams using ffmpeg
  • Safe Filenames: Sanitizes video titles by removing invalid filename characters

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Process Flow

  1. Fetches available video streams and audio stream
  2. Displays top 5 resolution options with file sizes
  3. Waits for user input (5 second timeout)
  4. Downloads selected video stream
  5. For adaptive streams:
    • Downloads audio stream separately
    • Merges video and audio using ffmpeg with H.264/AAC codecs
    • Removes temporary files
  6. Returns path to final video file
from Components.YoutubeDownloader import download_youtube_video

# Download with interactive selection
video_path = download_youtube_video("https://www.youtube.com/watch?v=dQw4w9WgXcQ")
print(f"Video saved to: {video_path}")
# Output: videos/Video Title.mp4
Downloaded videos are saved to the videos/ directory, which is automatically created if it doesn’t exist.
Requires pytubefix, ffmpeg-python, and system ffmpeg to be installed. The function handles errors gracefully and provides installation instructions if dependencies are missing.

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get_video_size

Helper function to calculate video stream file size in megabytes. 
get_video_size(stream) -> float
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stream
pytube.Stream
required
PyTube stream object to calculate size for
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size_mb
float
File size in megabytes (MB)

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Example

from pytubefix import YouTube
from Components.YoutubeDownloader import get_video_size

yt = YouTube("https://www.youtube.com/watch?v=dQw4w9WgXcQ")
stream = yt.streams.first()
size = get_video_size(stream)
print(f"Size: {size:.2f} MB")

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Output Format

Videos are saved with sanitized titles:
  • Invalid characters (|:?*<>"/\) are removed or replaced with hyphens
  • Format: videos/[Sanitized Title].mp4
  • Codec: H.264 (libx264) for video, AAC for audio

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Error Handling

The function catches all exceptions and provides helpful error messages:
  • Missing dependencies (pytube, ffmpeg-python, ffmpeg)
  • Network issues
  • Invalid URLs
  • Download failures
try:
    video_path = download_youtube_video(url)
except Exception as e:
    print(f"Download failed: {e}")

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