What are audio file formats?

ByMunyaradzi Mafaro

Audio file formats are different ways of storing digital audio data on computers. Audio files take the sound waves from a recording and turn them into numbers so a computer can work with them. There are many different audio file formats, each with their own qualities. The format tells the computer how to understand and play back the audio data. Some formats squish the data down to a smaller size while others try to keep as much of the original sound quality as possible.

Uncompressed vs compressed formats

Audio file formats can be either uncompressed or compressed:

Uncompressed audio formats

Uncompressed formats don’t do any squeezing of the audio data. They try to keep the sound quality very high and close to the original recording. This means the files are pretty big though. WAV and AIFF are common uncompressed audio formats.

Compressed audio formats

Compressed formats use smart math tricks to make the audio files a lot smaller. They may lose some sound quality, but it’s usually hard to notice. MP3, AAC, and OGG are popular compressed formats. There are two kinds of compression:

  • Lossy compression throws away some data to make files smaller. The quality is a little worse but files get much smaller. MP3 and AAC use lossy compression.
  • Lossless compression shrinks file size but keeps all the original data. When these files get uncompressed, the audio sounds exactly the same as the original. FLAC and ALAC use lossless compression.

Popular audio file formats

Let’s look at some of the most widely used audio formats today:

MP3 (.mp3)

MP3 is the most common compressed audio format. It’s been around since the 90s. MP3 uses lossy compression to make file sizes much smaller while still sounding pretty good. You can choose different compression settings – more compression means smaller files but worse sound. Most people can’t really hear the quality loss though, especially with higher bit rates. MP3 files are easy to play on almost any device.

WAV (.wav)

WAV is a common uncompressed audio format created by Microsoft and IBM. Since it doesn’t compress the data at all, WAV files are very high quality but also very large. WAV is often used when recording audio since it captures the original sound well. The files can be edited and converted to other formats later. Many computers and audio programs can easily play WAV files.

AAC (.aac, .m4a)

AAC is a newer lossy compressed format. It’s the standard audio format for YouTube, iPhones, and many streaming services. AAC files are similar in size to MP3s but can sound a bit better, especially at lower bit rates. So you can get files that are smaller or sound better than MP3. Almost all new phones and computers can play AAC files.

FLAC (.flac)

FLAC is a lossless compressed format. It makes files about half the size of WAV while sounding just as good. It’s a great choice if you want high quality audio in smaller files. FLAC uses smart compression to store only the audio data it needs. Many music fans like using FLAC to store their CDs digitally. It’s become quite popular and works on most newer devices.

AIFF (.aiff, .aif)

AIFF is an uncompressed format made by Apple. It’s very similar to WAV and also has very high quality with large file sizes. AIFF was commonly used on Mac computers but is less popular now. Still, many audio programs on Mac and Windows can open and save AIFF files.

OGG (.ogg, .oga)

OGG usually means the Vorbis lossy compressed format in an OGG container. It was made to be an open source alternative to MP3 and AAC. So anyone can use the format without paying royalties. The quality is similar to MP3 but OGG files can be a bit smaller. It never became as widespread as MP3 but some apps and websites use it to avoid license fees.

ALAC (.alac)

ALAC is a lossless compressed format made by Apple. It’s like FLAC but made to work well on Apple products. ALAC isn’t as widely supported as FLAC on other devices. Still, many Apple fans use it to store high quality audio since it’s built into iTunes and iOS.

Choosing an audio format

Think about these things when picking an audio format to use:

  • Compatibility – will it play on the devices and programs you want? MP3 and AAC work almost everywhere.
  • File size – do you need small files to save space or is quality more important? Compressed formats like MP3, AAC, and OGG make the smallest files.
  • Sound quality – is it important the files sound as good as possible? Uncompressed WAV and AIFF are great for perfect recordings. Lossless compressed FLAC and ALAC sound perfect too but in smaller files.
  • Your audio source – if you’re moving files from a CD or premium music service, you may want to keep high quality, so use FLAC or ALAC. If your audio is from an average streaming service, MP3 or AAC files will probably be good enough.
  • What you’re doing with the files – if you need to edit the audio, stick with uncompressed WAV or AIFF. If you’re just listening on your phone, MP3 or AAC will be just fine and save space.

There’s no perfect format for all uses. Think about what matters most to you and the trade-offs you’re willing to make. For most people, MP3 and AAC are great choices since they work everywhere and sound good enough on most headphones and speakers. If you’re an audio enthusiast, uncompressed or lossless compressed formats let you hear every detail in very high quality. For saving old CDs or tapes, FLAC is nice since the files will sound as good as the originals. Hopefully this overview gives you a better sense of the common audio format options out there and helps you choose which ones to use!

Munyaradzi Mafaro is a music enthusiast and he also likes to tackle topics of business, productivity, and the possibilities for growth in the digital world.