How Does Digital Music Work? An Explanation of the Different Audio File Formats, And Which One to Choose for Your Project
We use audio files every day, whether you are a musician or not! Audio files are everywhere: in the music you listen to on Spotify, in the songs included in your favorite CD, in your notation software, in your electronic keyboard, or in the voice messages you exchange with your friends.
Audio files are used so often that there are countless formats, tailored to different needs and situations. In this article, we’ll go through the most common audio file formats to analyze how they work and what each one is useful for. In other words, we’ll explain how audio files work.
Audio format categories
The different audio file formats fall into three main categories:
- Uncompressed audio: they store raw sound data, without making the files smaller. WAV is the most popular format for uncompressed audio.
- Compressed audio: these formats are used to make audio files smaller.
- Lossy: they throw away some audio data, like MP3 or AAC files.
- Lossless: they keep all the original data, like FLAC format.
- Performance instructions: they don’t contain audio, but musical instructions in code format, like MIDI files.
The most used audio file formats
1. MP3 (.mp3)
MP3 (MPEG-1 Audio Layer III) is the most popular audio format out there. It’s a lossy compressed audio format designed to considerably reduce the file size. It’s a small file size, compatible with almost every device and platform.
Despite removing a big part of the information, MP3 files don’t compromise audio quality, as they use psychoacoustic compression. Before eliminating any information, they analyze what humans can hear well. Then, they remove the less noticeable sounds and simplify similar frequencies to avoid duplicate data. Finally, they delete the quiet sounds muffled behind louder sounds.
This way, the resulting audio quality is reduced compared to uncompressed formats, but good enough for most listeners. MP3 format is a great option for streaming, everyday listening, or sharing music online.
2. WAV (.wav)
WAV (WAVeform Audio File Format) files are the industry standard for recording: large files that store high audio quality. In WAV files, audio is represented as thousands of samples that store sound values. For example, CD-quality audio uses 44,100 samples per second (44.1 kHz), and each sample contains 16 bits. That’s really a lot of information!
WAV is commonly used in professional recording and mixing, and is fully compatible with DAWs and editing software. It’s the best option for studio recording, mixing, mastering, or any professional audio work.
3. FLAC (.flac)
FLAC stands for Free Lossless Audio Codec; in other words, it compresses audio without losing any information. This format finds audio patterns and stores them more efficiently. Afterwards, the exact original audio can be reconstructed identically to the original WAV. It works like a ZIP file!
FLAC files are larger than MP3, but smaller than WAV (about 30 to 60%). They are popular among professionals and collectors, but not every platform or device supports them. That’s why they are commonly used for high-quality music libraries and archiving, but not among users.
4. ACC (.acc)
ACC (Advanced Audio Coding) is a newer lossy compression format. It’s basically an improved MP3, with better sound quality at similar bitrates. Nowadays, ACC is used in some modern media, such as Apple and YouTube.
AAC uses advanced compression algorithms to get a better frequency approach and stereo coding. In other words, it has a more efficient psychoacoustic modeling than the MP3 files. However, it’s still a lossy format, supported by most devices, but much less universal than MP3.
ACC is a good option for some mobile devices, like Apple, streaming services, or online platforms.
5. MIDI (.mid)
MIDI files are very different from the others. They are not considered audio files because they don’t store actual sounds, but musical instructions, such as notes, tempo, and performance data. MIDI files are the most lightweight of this list, and are easily editable in notation software and DAWs.
In MIDI format, music depends entirely on the playback device, so the same file can sound completely different on different systems.
MIDI files are used for composition, arranging, and other music production workflows. Electronic instruments and older video games use MIDI format too.
Apple’s audio file formats
Apple devices support every file format, just like any other device. However, they use some different audio formats than other devices. As this can be a bit confusing, we’ve listed them here:
- AAC: This format was not created by Apple, but it’s widely used on its devices, more so than MP3.
- ALAC (Apple Lossless Audio Codec): This is Apple’s equivalent to FLAC, created by Apple.
- AIFF: also created by Apple, and very similar to WAV.
- M4A: Apple container, often for AAC or ALAC format.
Final thoughts
Working with audio files can be challenging, as there are so many different formats. Most of them work perfectly well in most situations, but they have a few characteristics that differ from one another, and these can make a difference.
If you need help transcribing or producing your music, just get in touch with us, and we’ll have a professional musician work on it!
