If you like listening to songs, playing different audio files like podcasts, or planning on creating your own audio projects, then you should definitely learn about the different audio file formats and how they’re different from one another.
If you have heard about MP3, the high-res FLAC, OGG, or any other audio formats, you will learn about them in this article.
Based on the information in this post, you will be able to make an informed decision about which one you will likely prefer, and for which purpose these can be used, and will also learn how the different audio file formats impact the storage space as well as the sound quality.
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What are Audio Files?
An audio file is created for the sole purpose of storing audio information. An audio file format is the format, or the standard, in which the audio data is sorted within the file.
There is a long list of audio file formats currently being used around the world. While some have been around for decades, others have been superseded by superior technologies.
There are 3 major types of audio file formats:
- Uncompressed
- Lossless compressed
- Lossy compressed
Compressed vs. Uncompressed Audio Files
If you do not want to read the lengthy details, here is a brief comparison table between the three audio file types:
| Pros | Cons | |
| Uncompressed | Larger in size | Excellent audible quality |
| Lossless compressed | Small in size; easy to store Can recreate original audio data | Compression rate only up to 60% (max) Requires codecs |
| Lossy compressed | Compression rate up to 90% Can be very small in size | Requires codecs Cannot recreate lost or discarded data |
Uncompressed Audio File Format
The uncompressed audio file format, as indicated by the name, is a bit-for-bit copy of the original file created by the producer. In other words, the data inside such audio files is maintained as-is without compression.
A caveat of uncompressed files is that they take up larger space on the storage device, such as CDs or DVDs. Therefore, the preferred mode of carrying such large audio files is on discs, including Blu-rays.
Uncompressed audio files are created using Pulse Code Modulation (PCM). In this method, the amplitude of the analog audio wave is converted to binary values. Therefore, the closer the interval of each value, the higher the precision of the sound. This improves the overall quality. However, it also increases the size of the uncompressed file by including more data.
Some examples of uncompressed audio file formats include:
Lossless Compressed Audio File Format
There are some audio file formats that compress the data to save storage space. The original files are encoded and decoded using codecs (discussed ahead) that perform the compression and the decompression.
Lossless compression file formats are considered by people who want to save storage space while not having to improvise on the audio quality. Lossless compression is a smart compression mechanism where the original audio stream can be recreated even after eliminating some of the original data.
The compression part is done by getting rid of the redundant data that is being duplicated. The lossless compressed audio file just keeps that data where and how many times the data is duplicated, and it is inserted back into the stream during the decompression process.
Another way to go about it is by considering the removal of unnecessary data. For example, if the original audio file contained “1100001111000000,” the compressed audio file only needs to remember the “1s”. Therefore, the data stored will be “11____1111______,” where the underscore are blank spaces. This approach reduces the data that needs to be stored inside the audio file.
Some of the lossless compression algorithms can reduce the original file size by up to 60%.
Some examples of lossless audio file formats include:
- FLAC
- ALAC
- APE
Lossy Compressed Audio File Format
As the name implies, lossy compression audio file formats lose some of the original audio data, permanently. Unlike lossless algorithms, the psychoacoustic analysis used during the lossy compression gets rid of the sound data which seems inaudible to the human ear.
Some sounds that are being masked (which cannot be heard because of other sounds) are thus permanently removed from the audio files – hence the name; lossy audio files.
Once the data is removed, the quality of the audio deteriorates. This is one of the factors why bitrates are important for audio files (discussed further down this post).
On the positive side, lossy compressed audio files can significantly reduce the size of the original audio files by up to 90%! Of course, the greater the compression, the poorer the audio quality.
Some examples of lossy audio file formats include:
There are also a few other things to know about the different audio file formats, such as their bitrate, bit-depth, sample rate, etc. Let us briefly discuss them before moving on to the details about the different audio file formats.
What is Sample Rate?
When converting an analog signal to digital bits, Pulse Code Modulation takes samples of the wave after every fixed interval. The number of samples within 1 second is known as the sampling rate.
The close together the samples, the more accurately a compressed audio file can recreate its original state. Therefore, this means that the higher the sample rate, the greater the quality/fidelity o the audio file format.
Normally, the sampling rate for compressed audio files is 44,100 per second, or 44.1 Kilohertz (KHz).
What is Bit Depth?
Bit depth, also referred to as the “resolution” of an audio file, is precisely how many levels of amplitude an audio file can save. The higher the bit depth, the greater the dynamic range of the audio file, which in turn means that the compressed file could recreate the original audio file more accurately.
The sampling converts the analog signal into bits. Each sample has an associated amplitude value which is represented by a combination of bits. Normally, most audio file formats have a bit depth of 16 bits or 2 bytes. However, some high-res audio file formats also have a bit depth of 24 bits.
What is Bitrate?
Bitrate refers to the number of bits the audio file will transfer to audio. This is usually measured in Kilobits Per Second (Kbps), which essentially means how many bits per second will be transferred when the compressed audio file will be decoded.
The more the number of bits per second, the higher the quality of the audio.
Bitrate is normally used for lossy compression files, like MP3 because these files remove the data to compress the file size. If you ever try to download an audio file from the internet, you may come across multiple MP3 files where the files with lower bitrates are also smaller in size.
Different audio file formats usually have different bitrates. Here are a few examples of the maximum bitrates of some audio file formats:
Note: This does not mean that these file formats cannot be created with lesser bitrates.
| Audio File Format | Max Bitrate |
| MP3 | 320 Kbps |
| AAC | 320 Kbps |
| OGG | 500 Kbps |
| WMA | 576 Kbps |
Now that we understand the different types of audio files and the terms associated with them, let us take a look at all the audio file formats to date, and how are they different from one another.
All Audio File Formats
8SVX
Type: Uncompressed, Lossy Compressed
The 8SVX audio files can be both uncompressed and optionally, can be available as Fibonacci-delta lossy compressed files. These are 8-bit sampled files that support both mono and stereo audio.
Note that 8SVX files were originally derived from .IFF files, which is why they can have a .IFF file extension.
AAC
Type: Lossy Compressed
AAC, or Advanced Audio Coding, is actually the name of the standard used to compress the original audio file. Even so, the compressed file still maintains the quality which is very much close to the original content.
This file format was developed in collaboration between various companies including LG, Sony, Panasonic, Nokia, and NEC.
AC3
Type: Lossy Compressed
The .AC3 audio files are surround sound formats created by Dolby Laboratories. This format is primarily used on DVDs, Blu-rays, and other digital video formats.
The AC3 file format can store up to 6 audio channels, making it ideal for a 5.1 surround experience.
AIFF
Type: Uncompressed
Since the Audio Interchange File Format (AIFF) is uncompressed, it contains original, high-quality audio data. However, they are significantly larger. This format was created by Paragon Decision Technology but later acquired by Apple.
AMB
Type: Uncompressed
Files with the .AMB file extensions are created with Advanced Integrated Multidimensional Modeling Software (AIMMS).
An AMB audio file contains spherical surround sound information. Instead of just the horizontal plane, it also includes sound sources below and above the user. The transmission channels of this format do not carry speaker signals, as opposed to several other multichannel surround formats. Instead, they include a B-format representation of a sound field, which is decoded to the listener’s speaker configuration.
Although the AMB file format is uncompressed and this has excellent audio qualities, this file format did not quite catch on.
AU
Type: Uncompressed
AU Files are mostly used on Sun or other Unix-based operating systems and have gained popularity that some audio programs have also incorporated support for .AU files natively. They store audio content in 3 parts; a header, an annotation block, and the actual audio data.
AVR
Type: Lossy Compressed
AVR files are mostly outdated as they were used with the Atari ST computers. AVR files can contain audio in 8-bit or 16-bit octets and may have 1 or 2 channels. These files are not commonly used nowadays, which is why most media players do not support this format.
CAF
Type: Lossless Compressed
The CAF audio file, saved in the Core Audio Format, is based on Apple’s Core Audio technology and is very much similar to .AIFF and .WAVE formats. However, unlike those, a .CAF file supports any number of channels and does not have a 4GB size limit.
CDDA
Type: Uncompressed
A CDDA file is usually created when a CD is ripped using the CD Digital Audio specifications and then the audio is extracted using applications like iTunes. It is mostly used for saving CD audio data digitally, like on a computer.
CVS
Type: Lossy Compressed
The CVS audio file format contains audio information encoded using the Continuous Variable Slope Delta Modulation (CVSDM) codec, which is a method to encode 1 bit per 1 sample. It uses the lossy compression algorithm, thus reducing the overall size of the audio file.
CVU
Type: Lossy Compressed
A CVU audio file contains audio information encoded using the Continuous Variable Slope Delta Modulation (CVSDM) codec, just like a .CVS file. The only difference is that a CVU file has unfiltered content which is an alternative handler for a CVS/CVSD file but can be used with any bit rate.
DTS
Type: Lossless Compressed
The Audio data within a DTS file is encoded using the Digital Theater Systems (DTS) codec. Such files are usually used in home theaters for surround audio, provided it has the correct setup. It supports 6 or 8-channel audio, which means it stores 5.1 and 7.1 surround sound.
A DTS audio file is naturally big, but the lossless compression algorithm reduces its size while maintaining the audio quality.
FAP
Type: Lossy Compressed
An audio file in the PARIS Audio Format (PAF) is saved using the .FAP extension. These can also be saved in the .PAF extension.
A FAP file is created when a project is saved or recorded using the Ensoniq PARIS Digital Audio Workstation (DAW), which has now been discontinued. However, the FAP file format is still being used today by audiophiles since some other programs also support this format.
FLAC
Type: Lossless Compression
Free Lossless Audio Codec (FLAC) is an open-source and lossless compression format used for audio content, which creates a FLAC file. The format is very much like the .MP3 format, except that the FLAC encoder does not lose any audio data, hence maintaining the content’s quality like the original.
Moreover, it reduces the file size by approximately 60 percent, which makes this format more desirable than many other popular audio file formats.
HTK
Type: –
An HTK file contains audio data which is used by the Hidden Markov Model (HMM) toolkit, which is a speech-recognition toolkit used to predict the occurrence of unobservable events by analyzing their observable consequences. HTK files are created by converting other audio files into the HTK format.
IMA
Type: Lossy Compressed
IMA files lack an identifying header that specifies the file’s attributes and content. Therefore, the majority of media players are unable to play IMA files.
IMA audio files store 4-bit audio content and are compressed using the Interactive Media Association’s (IMA) Adaptive Differential Pulse Code Modulation (ADPCM) compression algorithm.
IRCAM
Type: –
An IRCAM file is an audio file developed by Institut de Recherche et Coordination Acoustique/Musique (IRCAM) – a French institute. It was primarily used by audio applications on the Berkeley Software Distribution (BSD) operating system, which is a Unix-based OS. However, since the IRCAM format files can also be saved using the .SF extension, .IRCAM has become much uncommon.
M4A
Type: Lossy Compressed
M4A files contain audio in the MPEG-4 format, which also supports different video, subtitle, and image formats. However, if only audio exists inside a file with the MPEG-4 format, it is saved using a .M4A extension.
An M4A file contains audio content encoded with either the Apple Lossless Audio Codec (ALAC) or Advanced Audio Coding (AAC) in the container format. It usually contains songs, podcasts, and maybe even audiobooks.
M4R
Type: Lossy Compressed
M4R files are normally created when converting a purchased song from iTunes into a ringtone. M4R files only support mono audio, which is why they are small in size. When an iPhone is linked to a computer using Apple iTunes, M4R files are immediately downloaded to the device.
MP2
Type: Lossy Compressed
An MP2 file consists of audio data formatted using the MPEG-1 Audio Layer II compression, which is a lossy compression. Although this file type has been mostly replaced by .MP3 files, .MP2 is still being used by digital radio and television broadcast platforms.
The audio on Video CDs (VCDs) and a few DVDs were also compressed using MP2 technology. A sample rate of 32, 44.1, or 48 kHz and bitrates ranging from 32 to 320 kbps are supported by the format’s standard version.
MP3
Type: Lossy Compressed
MP3 is a file format commonly used to contain an elementary stream of MPEG-1 Audio or MPEG-2 Audio encoded data.
The MP3 format significantly reduces the size of the file as compared to other audio formats while maintaining the same quality as a Compact Disc (CD), which is why it is ideal to store music and other audio content. MP3 files are now common and usually supported natively by built-in applications and programs in different operating systems.
NIST
Type: –
NIST files contain recorded audio saved in the Speech Header Resource (SPHERE) format created by NIST to work with speech recognition software, like Hidden Markov Toolkit.
OGA
Type: Lossless Compression
An OGA file contains audio data in the open-source Ogg audio container format, which can be encoded using different codecs that include FLAC, OggPCM, or Opus. OGA files are a subset of Ogg audio files, hence their file extension may be .OGG rather than .OGA.
OGG
Type: Lossless Compression
An OFF audio file saves the audio data inside an Ogg container that applies Vorbis to the data, which significantly reduces the size of the file. Ann OFF file can contain multiple audio streams simultaneously.
OPUS
Type: Lossy Compression
An OPUS file contains audio content that uses both SILK and CELT codecs to support variable bit rates ranging from 6 kb/s to 510 kb/s. It is stored in the Opus format, which is a lossy audio format designed primarily for online streaming of audio.
The Opus codec is mainly used for Voice Over IP (VOIP), in-game chat, or video conferencing.
PVF
Type: –
A PVF file contains recorded audio using Mgetty-voice (also known as Vgetty) – a software for Unix-based operating systems that acts like an answering machine with the aid of a voice modem. The file is saved in the Portable Voice Format (PVF).
RA
Type: Lossy Compressed
An RA file is an audio file compressed using the Real algorithm and used by the RealPlayer software. It has stream-while-downloading capabilities and can be compressed using various codecs with variable bit rates.
SD2
Type: –
SD2 is an audio file that was originally designed for Macintosh audio recording programs and to be used for exchanging audio content between applications. An SD2 file can contain both stereo and mono audio and also supports different bit depths and sampling rates.
SMP
Type: –
The SMP audio file was created by Turtle Beach to be used with PC-DOS. It supports mono audio with loop points. However, it has become an outdated technology and is not used in the modern world, therefore very few programs support this format.
SND
Type: Compressed
An SND file is an audio file that can be used by a multitude of programs. It was originally developed by Apple as a sound resource, but can also contain audio from an AKAI MPC sampler. These sound files can be used for games or any other programs.
SNDT
Type: Compressed
SNDT files are audio files used for the SNDTool software. It is used for audio files in an 8-bit mono sound format. Since it is not a popular format, not many programs support it.
SPH
Type: –
An SPH file usually contains a sound recording of a human in the NIST SPHERE format. These can then be used in speech recognition software as well. The SPH file is in a waveform format that has a 16 kHz sampling rate and uses a 16-bit linear Pulse Code Modulation (PCM).
SPX
Type: Lossy Compressed
An SPX file is an audio file encoded with the open-source Speex Audio codec and saved in the Ogg Vorbis container format. This file format is mostly used to store voice recordings for games, podcasts, sound effects, and sometimes music. It also supports 8 kHz, 16 kHz, and 32 kHz compression in the same bitstream as well as voice compression at 2 to 44 kbps.
TTA
Type: Lossless Compressed
A TTA file contains audio encoded with the open-source True Audio codec, which supports multichannel 8, 16, and 24-bit data in .WAV format. This format is ideal for users to compress audio by 30% to 70% of its original size losslessly, maintaining its original quality.
TXW
Type: Lossless Compressed
A TXW audio wave file contains samples used for the attack and loop sections created by the Yamaha TX16W sampler. This format is very much similar to the .WAV format and supports 16, 33, and 50 kHz samples, where each sample cannot be greater than 128K.
VOC
Type: Uncompressed
A VOC file contains compressed audio data and is used for Creative Labs soundcards. It can have audio clips, recorded sounds, or sound effects. The VOC file format significantly reduces the file size from the original source whilst maintaining its quality.
VOX
Type: Lossy Compressed
A VOX file stores recorded human audio in the ADPCM (VOX) format. It includes low-rate sampled digital voice data and computer telephony systems usually use this format, which is optimized for data size and vocal clarity.
W64
Type: Uncompressed
A W64 file is an audio file used by Sony’s audio editing programs. It is saved in Sony’s Wave64 format which removes the 4GB audio file limit, unlike Microsoft’s RIFF and WAV file formats. The W64 audio format is ideal for audio editors since it supports arbitrary sampling frequencies, bit depths, and channels.
WAV
Type: Uncompressed
The Waveform Audio File Format (WAV) is used to store waveform data in the WAVE format. It offers variable sampling and bit rates and is based on the RIFF file format, which is a container format.
The WAV file format is very common and mostly used for CD audio in a 44.1 kHz, 16-bit, stereo format.
WMA
Type: Compressed or Uncompressed
WMA files are saved using Microsoft’s proprietary Advanced Systems Format (ASF) container format and contain different types of audio data, such as music, voice narration, or sound effects. The audio can be encoded using several codecs including Windows Media Audio (WMA), WMA Pro, WMA Lossless, or WMA Voice codecs.
WV
Type: Lossy and Lossless Compressed
A WV file is an audio file that can be compressed with both lossless and lossy compressions. Usually, it is compressed using the WavPack Hybrid Lossless Compression. This compression format significantly reduces the file size (30% to 70%) and supports mono, stereo, and multichannel audio. Furthermore, it supports sampling rates ranging from 6 to 192 kHz.
WVE
Type: –
A WVE audio file is created by WaveEditor, which is audio editing software by CyberLink. However, it is also used by another audio editing software known as Filmora by Wondershare.
A WVE file mostly includes sound effects and other audio adjustments. PowerDirector video projects (.PDS files) frequently use the WaveEditor projects to export adjusted audio and sounds.
Closing Words
This article lists all of the popular and known audio file formats to date. Here, you will find the information on the audio file types, where and why they are used, amongst other useful information.
You will also learn the 3 different types of audio files and how they are different from one another.
There are many different audio files available today, each with its own benefits and downsides. Moreover, many software manufacturers have also introduced their proprietary audio file formats just for their own products, which contributes to the overall list of audio file formats.