What is ID3?

ID3 is a small piece of information stored physically inside the MP3 file (in the beginning or in the end of the file, depends on ID3's version). ID3 tags can contain various information about the MP3, like album name, song name, artist, original artist, genre, composer, releasing year, additional comment fields, etc.. Nowadays ID3s are de facto in audio world and they can be added to most of the audio formats and even to certain video formats in order to provide additional information of the file.