What You Should Know About Audio Formats

Olga Weis

Today you can find lots of audio formats in the Internet environment. Their format is usually determined by the file extension that goes after dot in the file name like .mp3, .wav, .ogg, .wma, etc.

A codec is a specific algorithm that encodes and compresses data into audio formats. For some file types, codecs are clearly defined. E.g. for the MP3 format the MPEG Layer-3 codec is always used, but for MP4 different codecs can be applied.

Often a codec and a format mean the same. Especially when a format always uses one and the same codec. But still it is important to distinguish between formats and codecs. A format is a kind of a container where to an audio or video signal can be recorded by using a certain codec. Some formats, like MP4 or FLV, can contain both audio and video streams.

Audio formats are divided into three groups depending on their compression type:

1. Uncompressed

The sound in such files is stored without compression and changes. Uncompressed format requires more storage space than other formats. That’s why it’s widely used only in professional audio and video applications where the sound should not have any quality loss before processing. The most popular uncompressed format is WAV.


WAV (Waveform in short) is one of the first and best audio formats that appeared back in 1991. It is used to store uncompressed audio records (PCMs) that are identical in sound quality to those that are available on audio CDs. On average, one minute of WAV file takes about 10 Mbytes. Often audio CDs are copied into WAV and then get converted into MP3 with the help of an audio converter.

2. Lossy

After the sound is compressed it can have some quality losses, thus, be modified. E.g. the sound frequencies that the human ear can’t detect are cut out. After that the decoded file differs from the original one in terms of the information recorded in it. But both files sound almost the same.

Highly spread lossy formats are as follows:


MP3 (MPEG Layer-3) is the most widely known audio format in the world. MP3, like many other lossy formats removes the sound that is not heard by the human ear, thereby reducing the file size. MP3 is not the highest quality audio format because of a file size - sound quality ratio. But due to its popularity and support by most devices, a lot of music is recorded and stored in this format. There are a lot of MP3 players for Mac that offer great performance and mp3 downloaders to fetch the best content from your favorite music.


This patented audio format offers bigger possibilities than MP3, e.g. the number of channels, sampling frequency, etc. and provides a better sound having the same file size. AAC is one of the best encoding sound lossy algorithms. The format is compatible with most devices. An AAC file can have such extensions as AAC, MP4, m4a, m4b, m4p, and m4r.


OGG is a media container that is used for all types of compression formats. It supports audio encoding by various codecs. Most often OGG uses the Vorbis codec. As for compression quality, the format is similar to MP3, but it is less popular and is less supported by audio players.


M4A is an abbreviation for MPEG-4 Part 14. This format was created by Apple in 2004 on the QuickTime File Format basis. iTunes allows you to download files in this exactly format which is a digital multimedia container used for storing audio components. MPEG-4 Part 14 files can have both the M4A and the MP4 extension. Their main difference is that MP4 files can store video. M4A format can have lossy compression if the FFC codec is used. But unlike other audio formats, compression is also possible without loss which can be done by using the Apple Lossless format.


The AC3 format is associated with Dolby Digital, a sound compression technology. AC3 is also known as Audio Codec 3. An AC3 file consists of 6-channel surround sound built by left, center, right, left surround, right surround and low frequency effects. AC3 format is used in DVD, Blu-ray, AVI, MP4 and other video formats as well as in cinemas and game consoles.

3. Lossless

This group of formats records and encodes the sound so that when decoding it can be fully restored.

The highly used formats include:


FLAC (Free Lossless Audio Codec) is one of the best lossless audio formats that doesn’t make changes in audio streams. The sound encoded with FLAC is identical to the original. The Flac format is often used for the sounds reproduced on high-level sound systems. It fits lots of devices and players and can replace MP3 for CD audio. So usually for listening to FLAC in players, it is pre-converted.


APE is a Monkey's Audio lossless codec that is one of the most popular algorithms today for compressing digital audio without losses. The APE format is used for storing compressed audio. The recording of such audio files requires a minimum storage space. The format allows to restore music in its original form with high sound quality.

You don’t need to unpack APE files as unzip tools require. You can play back compressed audio directly. Unlike such lossy codecs as MP3, WMA, AAC, etc. Monkey's Audio allows to save not only original sound, but additional data as well.


MKA (Matroska) is a lossless audio format, a form of audio container that supports several types of audio compression algorithms. It is associated with the MKV video format, but it supports only audio data. An MKA file requires both support of the standard Matroska format and a specific audio codec that was used for the tracks encoding.

MKA files are often met as external audio tracks to movies in foreign languages or as film director’s comments and multi-channel sound. Matroska audio files are also used as containers for high-quality multi-channel music.


WMA (Windows Media Audio) is an audio file format owned by Microsoft. Initially, it was introduced as an MP3 replacement, which, according to Microsoft, has higher compression characteristics. But some independent tests found this fact doubtful. The WMA format supports data protection via DRM.

What Format to Use?

  • If you grab and edit raw audio, uncompressed format is what you need because you can work with true quality of the audio. When you finish, you can convert it into a compressed file.
  • If you listen to audio tracks and need a great sound quality, lossless format is the best. But be ready to sacrifice your storage space for such files.
  • Lossy audio compression is Ok if you are not after top quality music or if your file has no music or if you don’t want to sacrifice your disk space. The human ear doesn’t really feel difference between lossless and lossy formats.

Taking into account that you have an ultimate guide to audio formats, you need a decent music player. Here is the guide to the best free music players for Mac.