1. Installation
  2. Downloading a playlist
    1. If you still get errors
  3. Downloading a large file and splitting it into several tracks
    1. Installing album-splitter
    2. Downloading the file from YouTube + Creating the split files
    3. Converting WAVs to AAC
    4. Dowloading an entire channel

Often you want to download videos from YouTube or extract audio from them.

There is no need to spend money on a GUI tool like 4k Video Downloader if you know how to use open-source tools like youtube-dl. It is really cool, and free!

If you tried to install youtube-dl in macOS you may have run into errors like zlib not installed etc. etc.

The trick is to install Python 3 using Homebrew and then run youtube-dl using python3 instead of the default Python of macOS, which is 2.7.

This was tested in macOS Catalina (10.15.1), macOS Big Sur (11.1) and macOS Monterey (12.1).

Installation

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#!/usr/bin/env bash

# install xcode components
xcode-select --install

# install audio encoder
brew install ffmpeg

#install python 3
brew install python3

#install pyenv
brew install pyenv

#install youtube-dl using homebrew
brew install youtube-dl

#install youtube-dl using python3 (this is likely not needed, but whatever...)
pip3 install youtube-dl

# install atomicparsley
brew install atomicparsley

Downloading a playlist

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youtube-dl https://www.youtube.com/playlist?list=PLamnoxId_aK2qxsln0OiDh9s3Pa1vgfvb \
--download-archive downloaded.txt \
--rm-cache-dir \
-x \
--audio-format m4a \
--audio-quality 200k \
--no-check-certificate \
--add-metadata \
--postprocessor-args "-metadata album='Album name, even with spaces!'" \
--embed-thumbnail \
-o '%(playlist_index)s. - %(title)s.%(ext)s'

Explanation of this long command, for the curious:

  • youtube-dl ← Base command
  • https://www.youtube.com/playlist?list=PLamnoxId_aK2qxsln0OiDh9s3Pa1vgfvb ← Playlist address
  • --download-archive downloaded.txt ← Keep a file with the list of the files already downloaded, so downloads can resume. Delete downloaded.txt to download everything again.
  • --rm-cache-dir ← Remove cache directory. Helps circumvent 403 Forbidden errors that sometimes happen.
  • -x ← Extract
  • --audio-format ← Use m4a for the output. You can replace with mp3 if you would like mp3 files.
  • --audio-quality 200k ← Bitrate for the produced files. Higher = larger files but better quality
  • --no-check-certificate ← Needed because without this some error would appear 😳
  • --add-metadata --postprocessor-args "-metadata album='Album name, even with spaces!" ← Sets the album name in the ID3 tags of the produced files. The single quotes ' are needed at the end to handle names with spaces
  • --embed-thumbnail ← Embeds the album art thumbnail in the file (nice for iTunes or whatever player you use).
  • -o '%(track_number)s. - %(title)s.%(ext)s' ← By default, youtube-dl appends the video id to the file names when it downloads videos, even if some disagree with this behaviour. This makes it so that only the track number, title and the extension make up the file name.

If you still get errors

If you have issues with the system using Python 2 instead of Python 3 (as it should) try this alternative that calls python3 directly:

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python3 $(which youtube-dl) https://www.youtube.com/playlist?list=PLamnoxId_aK2qxsln0OiDh9s3Pa1vgfvb -x --audio-format m4a --audio-quality 200k --no-check-certificate "-metadata album=\"Album name, even with spaces!\"" --embed-thumbnail -o '%(playlist_index)s. - %(title)s.%(ext)s'

Downloading a large file and splitting it into several tracks

We will use a script called album-splitter that you can find on GitHub.

Installing album-splitter

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git clone git@github.com:crisbal/album-splitter.git
cd album-splitter/
python3 -m venv venv
source venv/bin/activate
pip3 install .

Downloading the file from YouTube + Creating the split files

(from the original README here):

  • Copy the YouTube URL of the album you want to download and split
  • Find in the YouTube comments the tracklist with start-time and title
  • Create a copy of the tracks.txt.example, rename it as tracks.txt and delete the lines starting with #.
  • Open tracks.txt
  • Copy the tracklist in the file, adjusting for the supported formats
    • <start-time> - <title>
    • A track on each line
  • Run the script
    • Basic usage: python3 -m album_splitter -yt <youtube_url>
  • Wait for the Download and for the conversion
  • Wait for the splitting process to complete
  • You will find your tracks in the ./splits folder

Converting WAVs to AAC

Let’s install a WAV to AAC Converter:

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brew install fdk-aac fdk-aac-encoder

Save this as splits/convert_aac_256.sh.

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#!/usr/bin/env bash
for i in *wav; do
    fdkaac -b 256k "$i" &
done

Then, run the conversion script inside each sufolder whose files you want to convert, e.g.:

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cd splits/<subfolder>
../convert_aac_256.sh

This runs all conversions in parallel for fastest performance.

Dowloading an entire channel

Here is another goodie: How to download an entire channel. Replace everything up to CHANNELURL with the link of the channel you want to download, but keep the /videos suffix.

youtube-dl -f 'bestvideo[height<=480][ext=mp4]+bestaudio[ext=m4a][height<=480]/mp4' -citw -v https://www.youtube.com/user/CHANNELURL/videos

Will download all videos at 480p and in mp4+m4a format for maximum compatibility. Adjust to your preferences.

You can also just replace the link with the link of a playlist to download all videos on that playlist.