AAC (Advanced Audio Coding) and MP3 (MPEG-1 Audio Layer 3) are lossy formats for audio files. MP3, an audio-specific format, is now the de facto standard of digital audio compression for the transfer and playback of music on digital audio players. Designed to be the successor of the MP3 format, AAC generally achieves better sound quality than MP3 at similar bit rates. This difference in quality is more obvious at lower bitrates.

Comparison chart

AAC versus MP3 comparison chart
Edit this comparison chartAACMP3
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File extension .m4a, .m4b, .m4p, .m4v, .m4r, .3gp, .mp4, .aac .mp3
Portability Apple has promoted AAC - all iPods and iPhones play AAC files. However, not all music players support AAC files. Virtually all music players support MP3 files.
Format Audio Audio
MIME Type audio/aac, audio/aacp, audio/3gpp, audio/3gpp2, audio/mp4, audio/MP4A-LATM, audio/mpeg4-generic audio/mpeg
Developed by AAC was developed with the cooperation and contributions of companies including Fraunhofer IIS, AT&T Bell Laboratories, Dolby, Sony Corporation and Nokia a group of engineers from Europe, belonging to Philips, CCETT (Centre commun d'études de télévision et télécommunications), IRT and Fraunhofer Society
Released for public use on 1997 7th of July, 1994
Extended from Part 7 of the MPEG-2 standard, and Subpart 4 in Part 3 of the MPEG-4 standard. mp2
Algorithm Lossy Compression Lossy Compression
Handles Audio only Audio only
Popularity Popular because of iTunes and iPods. However, not as popular as MP3 De facto standard for audio files
Quality AAC offers better quality than MP3 at the same bitrate, even though AAC also uses lossy compression. MP3 offers lower quality than AAC at the same bitrate.
Original Name Advanced Audio Coding MPEG – 1 Audio Layer 3
Standards ISO/IEC 13818-7, ISO/IEC 14496-3 ISO/IEC 11172-3, ISO/IEC 13818-3

AAC vs MP3 audio quality

The AAC format was designed to be an improvement over MP3 in the following aspects:

Overall, the AAC format allows developers more flexibility to design codecs than MP3 does, and corrects many of the design choices made in the original MPEG-1 audio specification. This increased flexibility often leads to more concurrent encoding strategies and, as a result, to more efficient compression.

The MP3 specification, although antiquated, has proven surprisingly robust in spite of considerable flaws. AAC and HE-AAC are better than MP3 at low bit rates (typically less than 128 kilobits per second). This is especially true at very low bit rates where the superior stereo coding, pure MDCT, and more optimal transform window sizes leave MP3 unable to compete. However, as bit rate increases, the efficiency of an audio format becomes less important relative to the efficiency of the encoder's implementation, and the intrinsic advantage AAC holds over MP3 no longer dominates audio quality.

Licensing and Patents for AAC and MP3

No licenses or payments are required to be able to stream or distribute content in AAC format. This makes AAC a much more attractive format to distribute content than MP3, particularly for streaming content like Internet radio. However, a patent license is required for all manufacturers or developers of AAC codecs. It is for this reason FOSS implementations such as FAAC and FAAD are distributed in source form only, in order to avoid patent infringement.

On the other hand, Thomson, Fraunhofer IIS, Sisvel (and its U.S. subsidiary Audio MPEG), Texas MP3 Technologies, and Alcatel-Lucent all claim legal control of relevant MP3 patents related to decoders. So the legal status of MP3 remains unclear in countries where those patents are valid. However, while these patent and licensing issues affect companies, consumers are largely unconcerned and the popularity of the MP3 format has not abated.


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"AAC vs MP3." Diffen.com. Diffen LLC, n.d. Web. 2 Jul 2020. < >