Here’s a breakdown of all the main file formats:
MP3 (not hi-res): Popular, lossy compressed format ensures small file size, but far from the best sound quality. Convenient for storing music on smartphones and iPods, but doesn’t support hi-res. Nearly every digital device in the world with audio playback can read and play MP3 files, whether we’re talking about PCs, Macs, Androids, iPhones, Smart TVs, or whatever else. When you need universal, MP3 will never let you down.
Note that MP3 is not the same as MP4, even though their similar names might suggest otherwise.
AAC (not hi-res): An alternative to MP3s, it’s lossy and compressed but sounds better. Used for iTunes downloads, Apple Music streaming (at 256kbps) and YouTube streaming. AAC stands for Advanced Audio Coding. It was developed in 1997 as the successor to MP3, and while it did catch on as a popular format to use, it never really overtook MP3 as the most popular for everyday music and recording.
WAV (hi-res): The standard format all CDs are encoded in. Great sound quality but it’s uncompressed, meaning huge file sizes (especially for hi-res files). It has poor metadata support (that is, album artwork, artist and song title information). Compared to FLAC and ALAC, WMA Lossless is the worst in terms of compression efficiency but only slightly. It’s a proprietary format so it’s no good for fans of open source software, but it is supported natively on both Windows and Mac systems.
AIFF (hi-res): Apple’s alternative to WAV, with better metadata support. It is lossless and uncompressed (so big file sizes), but not massively popular.
FLAC (hi-res): This lossless compression format supports hi-res sample rates, takes up about half the space of WAV, and stores metadata. FLAC stands for Free Lossless Audio Codec. A bit on the nose maybe, but it has quickly become one of the most popular lossless formats available since its introduction in 2001. What’s nice is that FLAC can compress an original source file by up to 60% without losing a single bit of data. What’s even nicer is that FLAC is an open source and royalty-free format rather than a proprietary one, so it doesn’t impose any intellectual property constraints. FLAC is supported by most major programs (though not by Apple as they can’t control your usage) and devices and is the main alternative to MP3 for CD audio. With it, you basically get the full quality of raw uncompressed audio in half the file size — what’s not to love about it?
ALAC (hi-res): Apple’s own lossless compression format also does hi-res, stores metadata and takes up half the space of WAV. An iTunes- and iOS-friendly alternative to FLAC. While ALAC is good, it’s slightly less efficient than FLAC when it comes to compression. However, Apple users don’t really have a choice between the two because iTunes and iOS both provide native support for ALAC and no support at all for FLAC.
SDD (hi-res): The single-bit format used for Super Audio CDs. It comes in 2.8mHz, 5.6mHz and 11.2mHz varieties, but isn’t widely supported.
(hi-res) ?? The main claimed benefit of high-resolution audio files is superior sound quality over compressed audio formats.
Downloads from sites such as Amazon and iTunes, and streaming services such as Spotify, use compressed file formats with relatively low bitrates – such as 256kbps AAC files on Apple Music and 320kbps Ogg Vorbis streams on Spotify.
The use of lossy compression means data is lost in the encoding process, which in turn means resolution is sacrificed for the sake of convenience and smaller file sizes. This has an effect upon the sound quality – those formats aren’t telling the full story of our favourite songs.
This might be fine when you’re listening to Spotify playlists on your smartphone on the bus on the morning commute, but serious audiophiles and music fans should want better. This is where high-resolution audio comes in.
To illustrate why it should sound better than MP3, for example, let’s compare the relative bitrates. The highest quality MP3 has a bitrate of 320kbps, whereas a 24bit/192kHz file has a data rate of 9216kbps. Music CDs are 1411kbps.
The hi-res 24bit/96kHz or 24bit/192kHz files should, therefore, more closely replicate the sound quality the musicians and engineers were working with in the studio. And they could be that very same recorded file, too – these files are labelled as “Studio Masters” in some cases.
So Which Format Should You Use?
For most people, the decision is actually pretty easy:
- If you’re capturing and editing raw audio, use an uncompressed format. This way you’re working with the truest quality of audio possible. When you’re done, you can export to a compressed format.
- If you’re listening to music and want faithful audio representation, use lossless audio compression. This is why audiophiles always scramble for FLAC albums over MP3 albums. Note that you’ll need more storage space for these.
- If you’re okay with “good enough” music quality, if your audio file doesn’t have any music, or if you need to conserve disk space, use lossy audio compression. Most people actually can’t hear the difference between lossy and lossless compression.
Join me next month for “Test Reviews”