Monday, February 8, 2016

Audio File Formats

Wav, mp3, aif, aac, mp4... What are they? What's the difference between them?

Most people don't have to think about this topic, let alone these questions, but electronic musicians have to think about audio file formats every time they rip a CD to their hard drive, sync their iPod or phone, or play streaming audio over the internet. I'll explain each one of these file formats separately under three categories: "Uncompressed", "Lossless" and "Lossy".

These two audio formats are what you would use if you want to preserve the highest quality of a digital recording. Neither one of these two formats compresses the audio in any way, but the tradeoff is a big file size: 9-10x bigger than and mp3 file size of the same song!

AIFF – short for Audio Interchange File Format (.aif), developed by Apple in 1988

WAV – short for Waveform Audio (.wav), developed by Microsoft in 1992.

Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. The term lossless is in contrast to lossy data compression, which only allows an approximation of the original data to be reconstructed, in exchange for better compression rates.  Lossless compression also applies to digital images.

Apple Lossless - (.m4a) introduced by Apple Corporation in 1994.  What's the difference between AAC and M4A? Read this article.

Lossy compression is a data compression method which yields small file sizes, but from which the original data can never be totally reconstructed. Lossy compression will always results in generation loss: repeatedly compressing and decompressing a file will cause it to progressively lose quality. Lossy compression also applies to digital images.

MP3 - short for Motion Pictures Expert Group (MPEG-1) Audio Layer 3, developed in 1995

AAC - stands for Advanced Audio Coding
Pros: Designed to fix "serious performance flaws" in the MP3 format
Cons: some would view it as a proprietary format, only useable on iPods, iPhones, and other Apple Computer software, such as iTunes, but AAC files are compatible with Creative Zen Portable, Microsoft Zune, Sony PlayStation Portable (PSP), other portable media players, and mobile phones

WMA - stands for Windows Media Audio, developed by Microsoft in 1999

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