Ruby bindings for MusicBrainz libdiscid

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ruby-discid provides Ruby bindings for the MusicBrainz DiscID library libdiscid. It allows calculating DiscIDs (MusicBrainz and freedb) for Audio CDs. Additionally the library can extract the MCN/UPC/EAN and the ISRCs from disc.

ruby-discid supports all features from libdiscid 0.6, but will also work with any earlier version. If a feature is unsupported in the libdiscid version used ruby-discid will just return a default value. The version required for a feature is documented in the API documentation.


  • Ruby >= 1.9.0
  • RubyGems >= 1.3.6
  • Ruby-FFI >= 1.6.0
  • libdiscid >= 0.1.0


Before installing ruby-discid make sure you have libdiscid installed. See for more information on how to do this. For Windows see also the notes below.

Installing with RubyGems

Installing ruby-discid is best done using RubyGems:

gem install discid

Installing from package repository

For some Linux distributions packages are available:

Install from source

You can also install from source. This requires RubyGems and Bundler installed. First make sure you have installed bundler:

gem install bundler

Then inside the ruby-discid source directory run:

bundle install
rake install

bundle install will install additional development dependencies (Rake, Yard etc.). rake install will build the discid gem and install it.

Windows installation notes

On Windows you will need discid.dll available in a place where Windows can find it, see Search Path Used by Windows to Locate a DLL. You can install the discid.dll system wide, but it is recommended to place it in the local working directory of your application.

Also the architecture (32 or 64 bit) of the DLL must match your Ruby version. As the official build of libdiscid contains only a 32 bit version of discid.dll it is recommended to use the 32 bit version of Ruby.

If you want or need to use 64 bit Ruby you will have to compile libdiscid yourself. Refer to the libdiscid install instructions for further details.


Read only the TOC

require 'discid'

# Specifying the device is optional. If omitted a platform
# specific default will be used.
device = "/dev/cdrom"
disc =

Read the TOC, MCN and ISRCs

require 'discid'

device = "/dev/cdrom"
disc =, :mcn, :isrc)

# Print information about the disc:
puts "DiscID      : #{}"
puts "FreeDB ID   : #{disc.freedb_id}"
puts "Total length: #{disc.seconds} seconds"
puts "MCN         : #{disc.mcn}"

# Print information about individual tracks:
disc.tracks do |track|
  puts "Track ##{track.number}"
  puts "  Length: %02d:%02d (%i sectors)" %
      [track.seconds / 60, track.seconds % 60, track.sectors]
  puts "  ISRC  : %s" % track.isrc

See the API documentation of DiscId or the files in the examples directory for more usage information.


The source code for ruby-discid is available on GitHub.

Please report any issues on the issue tracker.


ruby-discid Copyright (c) 2007-2021 by Philipp Wolfer [email protected]

ruby-discid is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

See LICENSE for details.