ID3

ID3v1 and its variations
- ID3v1: MP3 standard published in 1995 without a method for storing file metadata
- Eric Kemp proposed adding a 128-byte suffix to MP3 files to store metadata
- ID3v1 quickly became the de facto standard for storing metadata in MP3s
- ID3v1 uses ISO-8859-1 encoding and has specific size limits for each field
- ID3v1.1: Modification proposed in 1997 to add track number to the comment field
- ID3v1.2: Proposed in 2002 or 2003, enlarged fields and added a subgenre field, retained backward compatibility but had limited adoption

ID3v2
- New specification created in 1998, completely distinct from ID3v1
- ID3v2 tags are of variable size and usually placed at the start of the file
- ID3v2 tags load immediately, even during streaming
- Each ID3v2 tag consists of optional frames containing metadata
- ID3v2.3: Widely used version, introduced the ability to embed an image
- Chapters: ID3v2 Chapter Addendum allows jumping to specific locations or chapters, used in Enhanced podcasts, can be used in ID3v2.3 or ID3v2.4 tags
- Lyrics: Lyrics3v1 and Lyrics3v2 were tag standards implemented before ID3v2, always placed at the end of an MP3 file

Editing ID3 tags
- Tag editors enable precise editing of all fields or frames
- Audio players and file managers provide native editing of common fields or frames

Non-MP3 implementation
- ID3 tags can be used with AIFF and WAV files
- MP4 allows embedding of an ID3 tag

MP4 and its related concepts
- MP4 Registration Authority: Manages the registration of MP4 file format identifiers, ensures interoperability and compatibility, maintains a registry
- Microsoft's involvement: Developed the MP4 format, supports and enhances it in software products, provides tools and documentation
- ID3 in MP4: A metadata format used to store information about the content, enables better organization and categorization, widely supported by media players and software applications
- Interoperability: MP4 format ensures interoperability between different applications and devices, supported by various operating systems and media players
- Evolution and Adoption: MP4 has evolved over time, widely adopted as a standard format for multimedia content, used for video streaming, music distribution, and mobile applications.