Class Overview

The main notable classes in mutagen are FileType, StreamInfo, Tags, Metadata and for error handling the MutagenError exception.


A FileType is used to represent container formats which contain audio/video and tags. In some cases, like MP4, the tagging format and the container are inseparable, while in other cases, like MP3, the container does not know about tags and the metadata is loosely attached to the file.

A FileType always represents only one combination of an audio stream (StreamInfo) and tags (Tags). In case there are multiple audio streams in one file, mutagen exposes the primary/first one. In case tags are associated with the audio/video stream the FileType represents the stream and its tags. Given a file containing Ogg Theora video with Vorbis audio, depending on whether you use oggvorbis.OggVorbis or oggtheora.OggTheora for parsing, you get the respective tags and stream info associated with either the vorbis or the theora stream.

It provides a dict-like interface which acts as a proxy to the containing Tags instance.

>>> from mutagen.oggvorbis import OggVorbis
>>> f = OggVorbis("11. The Way It Is.ogg")
>>> type(f)
<class 'mutagen.oggvorbis.OggVorbis'>


Each FileType has an attribute tags which holds a Tags instance. The Tags interface depends mostly on each format. It exposes a dict-like interface where the type of keys and values depends on the implementation of each format.

>>> type(f.tags)
<class 'mutagen.oggvorbis.OggVCommentDict'>


Similar to Tags, a FileType also holds a StreamInfo instance. It represents one audio/video stream and contains its length, codec information, number of channels, etc.

>>> type(
<class 'mutagen.oggvorbis.OggVorbisInfo'>
>>> print(
Ogg Vorbis, 346.43 seconds, 499821 bps


Metadata is a mixture between FileType and Tags and is used for tagging formats which are not depending on a container format. They can be attached to any file. This includes ID3 and APEv2.

>>> from mutagen.id3 import ID3
>>> m = ID3("08. Firestarter.mp3")
>>> type(m)
<class 'mutagen.id3.ID3'>


The MutagenError exception is the base class for all custom exceptions in mutagen.

from mutagen import MutagenError

    f = OggVorbis("11. The Way It Is.ogg")
except MutagenError:
    print("Loading failed :(")