A-101 answers all your questions on the AAC file format.Read More
Your Intro to all things audio.
Welcome to Audiophile 101, your introduction to all things audio presented by Pocket Rock It Radio. From the simple to the not so simple questions Audiophile 101 will drop some audio knowledge in simplistic and easy to understand terms to help answer all your audio related questions. It’s our hope that with the help of the A-101 program you’ll become a better informed connoisseur of music.
In this chapter we will take a look at the AAC audio file format to answer the question, what is AAC?
AAC is a type of digital computer file used for storing audio information on your favorite computing device, and was originally designed to be used with Apple devices. AAC is a compression algorithm (rules a computer uses to shrink a digital file size) that was designed to be an improvement to, and replacement of the MP3 audio file format. Originally only available on Apple, and a few select platforms the AAC file format has now become more easily available on a much wider variety of devices.
Because AAC deletes the information from the file in order to compress the size of the original audio file it is considered a type of ‘lossy compression’.
AAC is an acronym for Advanced Audio Coding.
Nourishment for your noodle!
Both formats MP3 and AAC work by compressing the original audio format by removing (deleting) information. This makes them both lossy style audio formats.
AAC was designed to sound better and do a better job at deciding what should and should not be removed in comparison to the MP3 algorithm. Aside from just scientifically removing information AAC also functions in a similar way to lossless compression as AAC rewrites some of the original audio file in an effort to retain and store the data more economically instead of deleting it all together.
For more on how lossy compression works check out A-101: Chapter 2.3 – How are lossy audio files created?
No. There is no way to reverse the process of converting an audio file to AAC because during the process of conversion from the audios original format into an AAC the information is deleted, or rewritten to make the file size smaller. Technically you can turn an AAC file into a WAV or similar lossless audio formats, but since the information is deleted during compression there is no data saved to restore the original audio file so converting the file type will not make the audio file sound better.
A couple factors go into why it’s taken so long for AAC to gain traction and become a more widely adopted audio format. For one the format came along after MP3 was well established so it was fighting an uphill battle, and for the longest time the format was incompatible [wouldn’t work] with most operating systems or digital audio players outside of Apple products.
The AAC format was designed by the Apple Corporation in the early 2000’s, and back in those days it was common practice in the computing industry for companies to not carry or support their competitors software. This made AAC playback on PC and other devices more difficult than the already widely used and similar MP3 audio format. Already being established, and it’s ease of use made the MP3 a much more attractive product on non-Mac devices.
Bottom line MP3 being the favored son of the digital audio file wars came down to a matter of it was there first, and convenience. Meaning that if you were using the AAC format you were limited in who you could share it with and where you could use it.
Yes. And, not exactly. While in theory AAC should out perform MP3 that’s not always the case. Where you’ll find the AAC file format really shines above MP3 is at lower bit rates as it was designed to provide a superior listening experience at lower bit-rates.
However, when you begin to increase the bit rate of the audio file you’re listening to, to above 200 bits per second the MP3 file in most cases will match the quality of the AAC file format, and even sometimes exceed it.
This makes it so at lower bit rates (where data is an issue) the AAC file format would be ideal to utilize. However if you’re able to use audio files at a higher bit rate the two formats can become interchangeable, and in a lot of situations which file type to use becomes more of a case of user preference or device compatibility.
For more on how bit rate affects sound see – A-101 Chapter 3.5 – What is bit rate and why does it matter?
Now you know essentially what the AAC file format is all about, there is quite a bit of cross over information when it comes to the MP3 and AAC file formats so be sure to check out ‘A-101 – What is an MP3?’ to answer more questions you may have.
AAC was designed as a way to improve your listening experience at lower bit rates, and just improve the over all quality of your listening experience. We’ll let the folks with analytical computer software fight out which ones actually the best. We’re just here to give you some info, and enjoy the tunes.
Until next time, Happy Listening.