AAC vs. MP3: Which Audio Format Is the Best for Your Music?

AAC vs. MP3: which one to choose? Both are designed to carry audio, but there are some crucial differences that we dive into as well as explore how to convert AAC to MP3 files.

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AAC vs. MPEG-1 Audio Layer3 (MP3): what are their main differences? MP3 has been the standard format for music playback on different digital audio players. The Advanced Audio Coding (AAC) format, on the other hand, looks to become the successor of the MP3 format. Both these audio-specific formats are flossy formats meaning that they use compression to create smaller audio files. The 128 kbps setting, for example, will reduce the original file's size by 1/11. In the creation process, developers lose part of the original audio data. These flossy formats have allowed developers to package countless songs into scaled-down music players.

The release of MP3 for public consumption took place in 1994, three years before the AAC format came to the market. Moving Pictures Experts Group (MPEG) adopted the MP3 format to be part of their MPEG-1 standard before later extending it to MPEG-2 standard.

MP3 has since become the most popular audio format, especially for storage and streaming purposes. Most audio players also use this format as the default playback and storage standard. MP3 files have the .mp3 file extension.

Developers of the AAC format intended to improve the compression scheme used for creating the MP3 file format. The idea was to create a format with better quality. Nokia, Dolby Laboratories, AT&T-Bell Laboratories, and Sony Corporation all had a hand in the development of this file format.

MPEG adopted this format as part of both its MPEG-2 and MPEG-4 standards. New audio devices and media players support the AAC format which doubles as the default audio format for iPhone, iTunes, iPad, PlayStation 3, YouTube as well as iPod. The AAC format files have a host of file extensions including, .m4a, .aac, .m4p, .m4r, .3gp, .m4b, .m4p, and .mp4.

Let’s look at MP3 vs. AAC quality. While AAC versus MP3 sound capabilities don't vary considerably, AAC has the upper hand at lower bit rates. If you're working with bit rates lower than 128 kbps, you'll notice the difference. MP3 files will sound a little muddy and slurry while the AAC files maintain their brighter and clearer sound.

The AAC format leverages its optimal transform window sizes and pure MDCT to beat MP3 at these bit rates. While MP3 has sample frequencies ranging from 16 kHz to 48 kHz, AAC's sample frequencies range between 8 kHz to 96 kHz. With more sample frequencies, AAC developers can accurately reproduce the original files as they decrypt audio files.

With higher bit rates (192 kbps and above), the focus shifts from the audio format to the encoder. MP3 competes favorably and is surprisingly robust if you work with an efficient encoder. At high enough bitrates, you'll hardly notice the difference between these formats and the original files.

When compressing audio files to create MP3 or AAC files, developers compromise quality for smaller audio files. You, therefore, end up with smaller audio files, although the AAC tends to be smaller than the MP3 format. With AAC files, developers can lower bitrates reducing the files' size further than what MP3 files can achieve. The audio quality for AAC files remains intact in the process.

An example of a test of the file sizes, comparing the size of MP3 versus AAC files at the same encoding rate. As you can see, the MP3 files are slightly smaller in each of the different encoding rates. The files are slightly bigger, but there is a bit of an increase in quality with the AAC files.

256 Kbps

At 256 Kbps, the difference in the files is quite hard to notice, they are virtually indistinguishable when it comes to quality, and the MP3 does a fine job of carrying quality audio.

192 Kbps

At 192 Kbps we would say there is a slight difference in quality. However, the MP3 file is so much smaller that it could be preferable for those who need to save space. Though this is not such an issue with devices these days, it makes all the difference for things like audio streaming.

128 Kbps

At 128 Kbps we think the biggest sound difference is in the AAC. While MP3 files at this encoding rate tend to sound a bit muddy and distorted, the AAC files have stood up more as the file size decreases.

Developers have greater flexibility in the AAC format than MP3 when designing codecs. With this flexibility, you can simultaneously use multiple encoding strategies and compress your files more efficiently.

MP3 files can only store two channels of synchronous audio compared to AAC's 48 channels. This specification lets you compress multichannel audio on AAC with less hassle. You'll also have an easier time working with surround sound mixes.

With a pure MDCT, AAC boasts of higher encoding efficiency. The MP3 format, on the other hand, uses a hybrid coding system that comprises the overall encoding process. MP3's block size of 576 samples further reduces the coding efficiency. AAC uses 940 or 1024 samples, further enhancing the encoding.

When it comes to the accuracy of transient signals, AAC has the upper hand with the 128 samples block size compared to MP3's 192 sample size.

Do you want to correct the design choices on original MP3 files? The AAC format lets you create audio files with your preferred specifications. As you use your encoder, watch out for the encoding speed, which ultimately influences how your track sounds. Some AAC encoders may not leverage all of AAC's additional encoding tools. There is little wonder, therefore, that you won't notice the subtle differences between the MP3 and AAC audio files.

Are you looking to distribute your audio files? With no payment or license requirements, AAC is the right choice on this end. This format is also better for streaming content. The only patent requirements come into play when you choose to create AAC codecs.

For the MP3 format, some companies like Audio MPEG and Texas MP3 Technologies claim control over the patents. These patents do not, however, hold water in some countries. Such licensing and patenting issues have done little to lower the popularity of this file format.

MP3 files can play in pretty much any device and operating system, giving it more popularity than AAC files. iTunes and Apple Music users, however, prefer the AAC files. The AAC format may not necessarily play on every device, especially the Android and Windows devices. This subdued support for AAC files is since it is newer. On availability, Amazon MP3 is an excellent store for top-quality MP3 files. For AAC files, you'll find your favorite songs in Apple iTunes.

How should you choose between MP3 vs. AAC files? Which are most appropriate for your own needs? There are a few factors to consider before you make your decision.

• Compatibility: Will they work with your device? In the modern age, there aren’t many devices that can’t handle both, but AACs are slightly less supported than MP3s. We all know that MP3 files are one of the most widespread file types out there.

• AAC vs. MP3 file size: This isn’t such a big deal in modern times where we have devices with huge hard drives. Back in the 1990s, smaller files were a much bigger consideration. However, you may want to consider files for sending, uploading, and downloading.

• AAC vs. MP3 quality: AAC files might offer slightly more quality at a very similar file type, so if you are considering the sound and streaming quality you may go for this over the MP3 file. For example, if you compare AAC vs. MP3 320 Kbps, it’s better to choose AAC.