To begin with, let’s first categorize the different audio formats under three categories: ‘Audio Uncompressed Audio Formats,’ ‘Audio Formats with Lossy Compression,’ and ‘Audio Formats with Lossless Compression. Now then, let’s dive in and understand what compression is the differences between each of the three categories, and some of the audio formats that fall under each category.
Generally speaking, audio compression, be it lossy or lossless, is the process of compressing or shrinking down the size of an audio file and evening out the span between the loudest and softest parts of an audio recording to average out the audio and make it easier for ordinary people to comprehend. The process usually involves some loss of data (with lossy compression) and, in turn, quality in exchange for a smaller file size. However, frequently, the changes made during compression are not easily discernible, and one can barely determine the difference between the compressed and the original file.
Since compression degrades the audio quality to some extent, an obvious question arises,
‘ Why do we need to compress an audio file at all?’
Well, simply because an uncompressed audio file comprises the original/actual sound waves, which are then captured and converted into a digital form without much processing. And, since the file contains original sound waves, the amount of information and detail in the file tend to increase its size, causing it to end up consuming a lot of disk space.
A codec is one of the most important elements required to perform compression on an audio file. For the uninitiated, a codec can be either a hardware device or a computer program that can encode and decode the audio as it is transmitted and received. Similar to how the quality of a DAC and an audio file play their part in delivering a high-quality audio experience, a good quality codec also plays a crucial role in determining the kind of audio quality and listening experience one can expect from their device.
Types of Audio Formats
1. Uncompressed Audio Formats
Uncompressed audio formats are the most accurate and genuine representation of the original sound waves. The sound from uncompressed files is very similar to how it was recorded and intended to listen to. Since the files do not undergo any kind of compression, there is no loss of information, which results in a high-quality audio experience and a fairly large file size. Compared to most other audio formats, uncompressed audio formats offer the best audio experience of the lot.
(a) Pulse-Code Modulation (PCM)
It is one of the widely used formats when it comes to uncompressed audio files largely because the conversion process of an audio signal (present in a waveform) into a digital stream is carried out without a lot of alterations. And also, no compression at all. As a result, the format accurately represents the original analog sound. Due to this reason itself, PCM became the most commonly used audio format in CDs and DVDs, which were very popular back in the day.
(b) Waveform Audio File Format (WAV)
The WAV audio file format was developed by Microsoft and IBM back in the year 1991. And during that initial time, it used to be called ‘Audio for Windows.’ WAV, in a nutshell, is like a container for various audio formats, because of which, it can sometimes contain compressed audio formats. However, that is rarely the case, and most of the time, the files are uncompressed and present in the PCM audio format.
(c) Audio Interchange File Format (AIFF)
Similar to WAV, which Microsoft and IBM developed and largely intended for use on Windows, the AIFF format is an in-house format developed by Apple for its Mac lineup. Much like WAV for Windows, AIFF is a container for Apple, which can hold different kinds of audio formats. However, more than anything, it is a wrapper for the PCM format, specifically for the Mac. Note: Both WAV and AIFF are also compatible with Mac and Windows, respectively.
2. Audio Formats with Lossy Compression
Lossy compression is that compression that incurs a loss of data during the compression process. And since compression is required to shrink down the file size of an audio file, the trade-off for quality is acceptable in most use-case scenarios. Depending on how the compression is carried out, it can turn out to be either a good compression — with not much loss of data — or bad compression — that completely tampers the audio quality and introduces artifacts that alter the original audio. Since the smaller file size also accompanies a loss of data and audio fidelity, lossy compression is not the preferred choice in professional settings which demand high-quality audio.
(a) MPEG-1 Audio Layer 3 (MP3)
MP3 is a relatively older format than most other audio formats normally found in use today. Back when it was released, MP3 replaced the MIDI and WAV files that were widely used at that time and slowly made their way into the mainstream. And later, got adopted as the standard format used in audio CDs and various music portals. One of the main reasons for the widespread adoption of MP3 is its smaller file size, which the format manages to achieve using a lossy data compression algorithm that gets rid of some data (sound that is usually beyond the hearing capabilities of humans). And back in the day, since a majority of devices did not come with massive storage space like they do today, the size of an audio file was a major deterrent in choosing an audio format. Even today, most of the devices in the market come with support for MP3 audio files, which speaks for its popularity and widescale adoption.
(b) Advanced Audio Coding (AAC)
Designed to be a successor to the MP3 format, AAC offered better sound quality than MP3 and soon became one of the popular audio formats. However, despite its popularity, it could still not defeat MP3, which had completely dominated the audio industry by then. Although, when compared to MP3, AAC tops out with its advanced compression algorithm, which later helped it stand out against other compression algorithms with its better and improved sound quality. Despite MP3’s popularity, the AAC format can still be seen actively used on different platforms like YouTube, iDevices, PlayStation, Nintendo, and even Android.
(c) OGG (Vorbis)
Unlike most other audio formats, OGG is not an abbreviation. And therefore, it does not have a full form. However, it has its own advantages over other audio formats. Generally speaking, OGG is more of a multimedia container that can hold different types of compression formats, the most prominent being Vorbis. This is why these audio files are sometimes referred to as OGG Vorbis. Over the years, Vorbis has slowly made its way to popularity with two distinct features — one of them being the open-source nature — and the other — a better audio quality than most of the lossy audio compression formats. As of today, even though the format is not as widely used as MP3 and AAC, there are a select group of people who prefer open-source equivalent of services over their counterparts.
(d) Windows Media Audio (WMA) – Lossy
Going by its name, one can get an idea about the involvement of Microsoft, which apparently owns this proprietary audio format. WMA was essentially introduced to address some of the issues with the compression algorithm used in MP3. Microsoft managed to do a good job of fixing and bringing to light a better audio format that dealt with many compression quality issues. However, since it was a proprietary format, it did not find much traction in the audio industry. Despite having fixed some of the prominent issues that MP3 had, it still failed to find its place across different devices and platforms currently in use. However, due to its advantages over MP3, if one has to choose between using MP3 and WMA on a Windows platform, WMA appears to be a better choice between the two formats.
3. Audio Formats with Lossless Compression
Unlike lossy compression, which loses some data during the compression process and, in turn, alters the original audio quality, lossless compression, on the other hand, reduces the file size of an audio file by keeping the audio quality intact without any loss of data. And since there is no data loss in compression, the audio quality is not compromised, making these formats a preferred choice for use in a professional environment. While the bigger file size might not be a deal-breaker for some, people with limited storage space on their devices might need to resort to using other audio formats.
(a) Free Lossless Audio Codec (FLAC)
FLAC is an open format that has rapidly become one of the most popular formats for the high-quality audio experience. It is pretty similar to MP3 in some ways, but lossless, which is why, unlike MP3, it does not undergo any loss of data during compression and offers an actual representation of the original audio, much like a CD-level quality in a smaller file size. Over the years, different platforms and devices have started supporting the FLAC format, which has, in turn, evolved FLAC as an alternative to the very popular MP3 format.
(b) Apple Lossless Audio Codec (ALAC)
Similar to FLAC, the ALAC format also offers an original audio quality experience but in comparatively smaller file size. The file size reduction, however, does not involve any data loss during the compression process. Despite its similarities with FLAC, ALAC does not share the same popularity and range of supported platforms and devices since it is designed to only work with Apple products. Conversely, users with an Apple device cannot natively use the FLAC format. And therefore, have to resort to its equivalent for Apple devices, ALAC.
(c) Windows Media Audio (WMA) – Lossless
WMA – lossless is very much similar to WMA – lossy, which is also a proprietary audio format owned by Microsoft. And apart from a lot of similarities, the two formats differ in the kind of audio quality they offer, with WMA – lossless offering the highest quality between the two due to its efficient compression.
Conclusion
After going through the different audio formats listed above, you must have acquired a recapitulation, based on your requirements, as to which format is the right fit for your needs. However, in case you haven’t got one, here’s a quick breakdown to make things simpler. If you are someone whose work involves working in and out with audio files, you do not want to compromise on the original audio quality. And therefore, using Uncompressed Audio Formats (PCM, WAV, AIFF) is your way to go. On the other hand, if you want to pick a format to listen to decent-quality music, you should be fine using Formats with Lossy Compression (MP3, AAC, OGG – Vorbis, WMA – Lossy). Whereas on the contrary, if you do not want to compromise on the audio quality and want to listen to high-quality music, then Formats with Lossless Compression (FLAC, ALAC, WMA – Lossless) is what you need. However, at large, using Formats with Lossy Compression, especially AAC, OGG (Vorbis), and MP3, should be ideal for most people on a regular basis in a non-professional setting.
