ruby-mp3info

http://github.com/moumar/ruby-mp3info

Description

ruby-mp3info read low-level informations and manipulate tags on mp3 files.

Features/Problems

Written in pure ruby
Read low-level informations like bitrate, length, samplerate, etc...
Read, write, remove id3v1 and id3v2 tags
Correctly read VBR files (with or without Xing header)
Only 2.3 version is supported for writings id3v2 tags
id3v2 tags are always written in UTF-16 encoding

Synopsis

require "mp3info"

# Read and display infos & tags

Mp3Info.open("myfile.mp3") do |mp3info|
  puts mp3info
end

# read/write tag1 and tag2 with Mp3Info#tag attribute
# when reading tag2 have priority over tag1
# when writing, each tag is written.

Mp3Info.open("myfile.mp3") do |mp3|
  puts mp3.tag.title
  puts mp3.tag.artist
  puts mp3.tag.album
  puts mp3.tag.tracknum
  mp3.tag.title = "track title"
  mp3.tag.artist = "artist name"
end

# tags are written when calling Mp3Info#close or at the end of the #open block

### access id3v2 tags

Mp3Info.open("myfile.mp3") do |mp3|
  # you can access four letter v2 tags like this
  puts mp3.tag2.TIT2
  mp3.tag2.TIT2 = "new TIT2"
  # or like that
  mp3.tag2["TIT2"]
  # at this time, only COMM tag is processed after reading and before writing
  # according to ID3v2#options hash
  mp3.tag2.options[:lang] = "FRE"
  mp3.tag2.COMM = "my comment in french, correctly handled when reading and writing"
end

### image manipulation

file = File.new('input_img','rb')
Mp3Info.open '1.mp3' do |m|
   pictures = m.tag2.pictures # array of images :
   pictures.each do |description, data|
      # description ends with (.jpg / .png) for easy writing to file
      File.binwrite(description, data)
  end
  m.tag2.remove_pictures # remove all images

  m.tag2.add_picture(file.read) # add a single image to APIC tag
  # **optionally**, you may include options for the image tag to add_picture():
  # options = { mime: 'jpeg|gif|png', description: "description",
  #             pic_type: 0 }
  # There is no need to specify mime or options because the mime is guessed based on the input image
  # Only one image is permitted in the mp3 for compatibility. add_picture() overwrites all previous images.
  # Please note:
  # If supplying :mime option just supply the mime 'jpeg', 'gif' or 'png', the code adds the "image/.." for you!
  # e.g. m.tag2.add_picture(file.read, mime: 'jpeg', pic_type: 3) gets a mime "image/jpeg"
end

Requirements

iconv when using ruby 1.8

Install

gem install ruby-mp3info

Developers

After checking out the source, run:

$ rake newb

This task will install any missing dependencies, run the tests/specs, and generate the RDoc.

License

GPL-3.0

TODO:

encoder detection
support for more tags in id3v2
generalize id3v2 with other audio formats (APE, MPC, OGG, etc...)

vngrv/ruby-mp3info