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A tag editor (or tagger) is a piece of software that supports editing metadata of multimedia file formats, rather than the actual file content. These are mainly taggers for common audio tagging formats like ID3, APE, and Vorbis comments (for example Windows Media Player and iTunes), but can also be taggers for JPEG, PDF and TIFF metadata (for example iPhoto).

A common purpose of tag editors is to correct and sort multimedia files, for example music collections. This often happens in a batch processing mode so that one doesn't have to manually edit every file on its own.

Audio files editing techniques[link]

Manual[link]

Most media player programs, such as iTunes or Winamp, allow users to manually edit tag and song file information. They can edit many advanced fields, including composer, release year, etc. Most players can automatically look up CD information from Gracenote — a database that contains track information for millions of CDs.

There are also many programs dedicated to the task of tag editing. These programs provide complex tag editing capabilities, such as batch editing, creating tags from filenames and vice versa, so they are useful when there's a need for editing a large number of files.

Automatic[link]

Comparing already-existing tag information to online music databases[link]

One type of tag editor compares the already-existing information in a song file's tag to information from online music databases, such as Gracenote / Discogs / freedb / Zortam Music Internet Database (ZMLIMD) or MusicBrainz. If the already-existing tag information matches song information of a song from an online music database, then the tag information and information about the song (such as song name and album) can be changed according to that song information match.

Acoustic fingerprinting[link]

An acoustic fingerprint is a unique code generated from an audio waveform. Depending upon the particular algorithm, acoustic fingerprints can be used to automatically categorize or identify an audio sample. Practical uses of acoustic fingerprinting include broadcast monitoring, identification of music and ads being played, peer-to-peer network monitoring, sound effect library management, and video identification.

Hash function[link]

In hash function, for audio identification, such as finding out whether an MP3 file matches one of a list of known items, one could use a conventional hash function such as MD5, but this would be very sensitive to highly likely perturbations such as time-shifting, CD read errors, different compression algorithms or implementations or changes in volume. Using something like MD5 is useful as a first pass to find exactly-identical files, but another, more advanced algorithm is required to find all items that would nonetheless be interpreted as identical to a human listener.

List of tag editors[link]

There are many available tag editors. Significant ones are mentioned here. Also, many media players, including the standard players iTunes and Windows Media Player, provide tagging features – these are not listed separately here.

Audio-only[link]

• Mp3tag, a widely used Windows freeware supporting most of audio formats including MP3, WMA, MP4, OGG, MPC and APE files. It has many features and supports embedded album art. It can access a few online databases like MusicBrainz and discogs.
• Tag&Rename, a shareware (30 days free trial) for Windows.
• EasyTAG, a free and open source package for Linux and Windows written in C. Supports many formats and standards as well as embedded album art.
• Media Catalog Studio, a shareware media player for Windows that edits tags in MP3, MP4, WMA, OGG, MPC, APE files.
• Ex Falso (software), a free package for Windows, Linux, Mac OS, and FreeBSD. It is associated with Quod Libet (software) and depends on OSS or ALSA, GTK, and Python.
• Jaikoz, a commercial package, available for Windows, Linux and Mac OS X written in Java that uses the MusicBrainz database for auto-tagging. Supports embedded album art and auto-lyrics
• MusicBrainz Picard and iEatBrainz – use MusicBrainz database and fingerprinting.

Linux only[link]

• cuetools, a free and open source package for Linux. Supports many formats, and can read audio tag from a .CUE file.
• lltag, a free and open source package for Linux. Supports many formats and standards, and can access online CDDB databases. Besides, can rename audio files based on their tags.

Image-only[link]

• DigiKam, for Windows, Linux, Mac OS, and FreeBSD
• iPhoto, for Mac OS
• Picasa, for Windows, Linux and Mac OS.