What is M4A?
M4A is an audio file format using the MPEG-4 container format but contains only audio data, typically compressed using AAC (Advanced Audio Coding) or Apple Lossless (ALAC) codecs. Popularized by Apple through iTunes, M4A has become a standard for digital music distribution.
The format offers better sound quality than MP3 at the same bit rate and supports rich metadata including album art, chapter markers for audiobooks, and more.
History
- 2001: MPEG-4 Part 14 standard published
- 2003: Apple adopts AAC for iTunes
- 2004: .m4a extension standardized
- 2004: Apple Lossless (ALAC) introduced
- 2011: ALAC made open source
Key Features
- AAC Compression: Better quality than MP3
- Lossless Option: ALAC codec available
- Rich Metadata: Album art, tags
- Chapter Markers: For podcasts/audiobooks
- DRM Capable: FairPlay protection
- Wide Support: Most modern devices
Common Uses
- iTunes and Apple Music libraries
- High-quality music distribution
- Podcast and audiobook production
- Digital music streaming services
Advantages
- Better audio quality than MP3
- Efficient AAC compression
- Lossless option with ALAC
- Excellent metadata support
- Native Apple ecosystem support
Limitations
- Less universal than MP3
- Some older devices lack support
- Can contain DRM restrictions
- Slightly larger than highly compressed formats
Technical Information
M4A uses the MPEG-4 Part 14 container with AAC-LC, HE-AAC, or Apple Lossless audio codecs. The format provides excellent audio quality with efficient compression.
| File extension | .m4a |
| MIME type | audio/mp4, audio/x-m4a |
| Developed by | Apple |
| First released | 2004 |
| Audio codecs | AAC, ALAC |
| Bit rates | 64-320 kbps (AAC) |
| Sample rates | 8-96 kHz |