AAC and MP3 are popular lossy file formats which compress digital audio by removing “unimportant” bits of information. The result is a smaller file at the expense of sound quality. We’ll take a look at AAC vs MP3 files and see if one is actually better than the other.
How Audio Files Are Stored
Computers create and store audio files in a variety of formats that fall into one of three categories.
- Uncompressed: Retains all of the sonic information in the file; large file size; formats include WAV and AIFF
- Compressed (lossless): Retains the quality of an uncompressed file; medium file size; formats include FLAC, ALAC, and WMA
- Compressed (lossy): Compresses and removes non-essential detail; smallest file size; degradation in quality from a lossless/uncompressed file; formats include AAC and MP3
What Is Bit Rate?
When it comes to AAC vs MP3, bit rate essentially refers to the amount of data stored in the file. A higher bit rate represents better quality compared to a lower one.
You’ll typically see AAC and MP3 files with bit rates like 128Kbps (kilobits per second), 192Kbps, 256Kbps, and 320Kbps. Streaming services usually offer different bit rates in their settings, with higher ones requiring more data for playback.
What Is an AAC File?
AAC stands for Advanced Audio Coding. It came out in 1997 as the successor to MP3s as the “best” lossy file format. The general consensus is that AAC files are, in fact, better than MP3s in terms of quality, even at the same bit rate (more on that in the conclusion). AAC’s advanced compression algorithm is thought of as more “efficient” than an MP3’s, and thus, of higher quality.
There’s a common misconnection that Apple developed AAC, but it was actually a collaboration between Bell, Nokia, Sony, Panasonic, and LG, amongst others. Apple simply introduced the format to mainstream consumers, announcing in 2003 that iTunes and iPods would support AAC files.
How Do AAC Files Work?
Like all compressed, lossy formats, AAC files must sacrifice certain information to encode a file that takes up minimal hard drive space. Usually information on either end of the frequency spectrum is the first to go—the highest highs and the lowest lows. For the average listener, an AAC file at a medium or high bit rate is more than adequate.
What Is an MP3 File and How Does It Work?
MP3 is an abbreviation of MPEG-2 Audio Layer III. It is a type of lossy audio file that originally came out in 1991 and received an update in 1998. Just as with AAC files, MP3s use data encoding compression to shrink file size. Part of the compression algorithm involves discarding sonic information outside the range of human hearing, which is a method sometimes called psychoacoustic modeling.
MP3s are more widely recognized by the general public than AACs.
AAC vs MP3: Which Is Better?
So, which format dominates the AAC vs MP3 debate? Truth be told, the differences are mostly negligible—at least at bit rates of 128Kbps or higher. Below that, you’ll find that AACs sound better than MP3s, but again, as the bit rate increases, the quality differences diminish.
And there you have it! AAC vs MP3 formats are very similar, even if the former was designed to be superior.