FLAC allows third-party applications to register an ID for use with FLAC APPLICATION metadata blocks. Contact the FLAC-dev mailinglist to register an ID or to change an existing ID. Your request should at least contain the application ID, application name and a contact e-mail address. An application URL and specification URL should be mentioned too, if applicable.

The ID request should be 8 hexadecimal digits and not conflict with any existing IDs (see the table below for all currently registered IDs). This 32-bit number will be stored big-endian in the block.

Information about your application (but not your e-mail address) will show up on this page in the ID directory. You can also provide a URL to your application and a URL reference to the specification of your application's APPLICATION block.

id directory
Here is a list of all registered IDs and their applications:

ID Application
41544348 - "ATCH" FlacFile
42534F4C - "BSOL" beSolo
42554753 - "BUGS" Bugs Player
43756573 - "Cues" GoldWave cue points (specification)
46696361 - "Fica" CUE Splitter
46746F6C - "Ftol" flac-tools
4D4F5442 - "MOTB" MOTB MetaCzar
4D505345 - "MPSE" MP3 Stream Editor
4D754D4C - "MuML" MusicML: Music Metadata Language
52494646 - "RIFF" Sound Devices RIFF chunk storage
5346464C - "SFFL" Sound Font FLAC
534F4E59 - "SONY" Sony Creative Software
5351455A - "SQEZ" flacsqueeze
54745776 - "TtWv" TwistedWave
55495453 - "UITS" UITS Embedding tools
61696666 - "aiff" FLAC AIFF chunk storage
696D6167 - "imag" flac-image application for storing arbitrary files in APPLICATION metadata blocks
7065656D - "peem" Parseable Embedded Extensible Metadata (specification)
71667374 - "qfst" QFLAC Studio
72696666 - "riff" FLAC RIFF chunk storage
74756E65 - "tune" TagTuner
78626174 - "xbat" XBAT
786D6364 - "xmcd" xmcd