AAC Audio (MIME: audio/aac) is a lossy audio codec standardized by ISO/IEC as part of the MPEG-2 and MPEG-4 specifications. It is designed to be the successor to MP3, offering improved sound quality at the same bitrate.
History and Development
AAC (Advanced Audio Coding) was developed by a consortium including AT&T Bell Labs, Fraunhofer IIS, Dolby, Sony, and Nokia. It was standardized in 1997 as part of MPEG-2 and later MPEG-4. AAC became mainstream when Apple adopted it as the default format for iTunes Store in 2003 and later for Apple Music.
Technical Specifications
- Compression: Lossy (multiple profiles: LC, HE, HE-v2)
- Bitrate: 8-529 kbps
- Sample rates: 8-96 kHz
- Channels: Up to 48 channels
- Container: M4A, MP4, 3GP, ADTS
- Profiles: Low Complexity (LC), High Efficiency (HE), HE-v2
Common Use Cases
AAC is the standard for Apple Music, iTunes, YouTube, streaming platforms, and mobile applications. It's the default audio codec for iOS, Android, and most modern devices.
AAC vs Similar Formats
- AAC vs MP3: AAC produces better quality at the same bitrate, especially below 128 kbps. Both are widely supported.
- AAC vs OGG: Similar quality. AAC has better platform support (Apple, Android); OGG is open-source.
- AAC vs Opus: Opus is technically superior, especially for low bitrates and voice. AAC has broader hardware support.
How to Open and Edit
AAC plays on all Apple devices, Android phones, and modern web browsers. VLC, Windows Media Player, and all major media players support AAC. Edit with Audacity or Adobe Audition.
Frequently Asked Questions
Is AAC better than MP3?
Yes, technically. AAC provides better audio quality at the same bitrate, particularly noticeable at lower bitrates (≤128 kbps). At 256+ kbps, the difference is minimal.
What is the difference between AAC and M4A?
AAC is the codec; M4A is the file container. An M4A file typically contains AAC-encoded audio. Think of it like MPEG-4 video in an MP4 container.