getID3() is a PHP script that extracts useful information from MP3s & other multimedia file formats:

Tag formats:
- ID3v1 (v1.0 & v1.1)
- ID3v2 (v2.2, v2.3 & v2.4)
- APE tags (v1 & v2)
- (Ogg) VorbisComment
- Lyrics3 (v1 & v2)
- IDivX
Lossy Audio-only formats:
- MP3, MP2, MP1 (MPEG-1, layer III/II/I audio, including Fraunhofer, Xing and LAME VBR/CBR headers)
- Ogg Vorbis
- Musepack (versions SV4-SV8)
- AAC & MP4
- AC-3
- DTS (including DTS-in-WAV)
- RealAudio
- TwinVQ (VQF)
- Speex
- Digital Speech Standard (DSS)
- Audible Audiobooks
- Adaptive Multi-Rate audio codec (AMR)
Lossless Audio-only formats:
- WAV (including extended chunks such as BWF and CART)
- AIFF
- Monkey's Audio
- FLAC & OggFLAC
- LA (Lossless Audio)
- OptimFROG
- WavPack
- True Audio (TTA)
- LPAC (Lossless Predictive Audio Compressor)
- Bonk
- LiteWave
- Shorten
- RKAU
- Apple Lossless Audio Codec
- RealAudio Lossless
- CD-audio (*.cda)
- NeXT/Sun .au
- Creative .voc
- AVR (Audio Visual Research)
- MIDI
- Direct Stream Digital (DSD) Storage Facility files (DSF)
Audio-Video formats:
- AVI
- Matroska (WebM)
- ASF (Windows Media Audio (WMA), Windows Media Video (WMV))
- MPEG-1 & MPEG-2
- Quicktime (including MP4)
- RealVideo
- NSV (Nullsoft Streaming Video)
- AMV (video MP3 player video)
Graphic formats:
- JPEG
- PNG
- GIF
- BMP (Windows & OS/2)
- TIFF
- SWF (Flash)
- PhotoCD
Data formats:
- ZIP
- TAR
- GZIP
- ISO 9660 (CD-ROM image)
- CUEsheets (.cue)
- SZIP
- PDF
Metadata types:
Formats identified, but not parsed:
- RAR
- MS Office (.doc, .xls, etc)

getID3() can write:
Note: Tag writing (for all file and tag formats) is barely alpha-quality code, and needs considerable rewriting, and is generally unsupported.
Use with caution, and expect that things may be incomplete or broken.

ID3v1 (v1 & v1.1)

ID3v2 (v2.3, v2.4)

APE (v2)

Ogg Vorbis comments

FLAC comments

Viewable source files for v1.9.24:

Can I use getID3 in my commercial program?

Note that getID3() is multi-licensed under several "free" licenses, notably GPLv1, GPLv2, GPLv3, LGPL, MPL.

The below section deals with GPL specifically:

The GPL is a little complicated, especially when mixing with non-GPL code. There is a FAQ here that may (or may not) help: https://www.gnu.org/licenses/gpl-faq.html

My interpretation of it is that if your code is only loosely tied to getID3 it would be considered a separate program and have no restriction on what license you use. For example, if getID3 sits in its own directory and your code checks to make sure it is there and can still work (or at least not crash, just give a warning like "getID3 files not found, cannot process metadata") if getID3 is missing, then it is a separate program. The user could download a new version of getID3 and upgrade that portion themselves, since it sits by itself.

On the other hand, if you take functions from getID3 source and include it in your own code directly, then it is an integral part of your program and you would need to release your code under the GPL (or compatible license).

Licensed gCL (commercial) users

This is the official list of licensed getID3 Commercial Licensees:

cosmicsoft [effective 2006-Aug-18]
wimpyplayer [effective 2006-Oct-18]
ViziMetrics, Inc. [effective 2007-Mar-25]
Cinesoft [effective 2007-Jun-05]
ScreenTonic [effective 2007-Jun-06]
Website Music Player [effective 2007-Aug-21]
Jon Lewis [effective 2008-Mar-13]
bandcamp [effective 2020-Sep-09]

Use of getID3 by anyone not in the above list must abide by the terms of the GNU Public License (GPL).
Note: existing gCL licences remain valid, but new ones are no longer offered.