What types of audio formats are available and how do they differ?
At some stage during recording audio, you'll ask yourself which audio format you should select for storing the data. Virtually all common recording programs offer a variety of options, from highly compressed MP3 formats to uncompressed WAV files. In the maze of audio formats that can be used, however, selecting the right one is not always clear. Here, we explain which audio formats are available and where the differences between the formats lie.
From MP3 to WAV:
Everything you need to know about audio formats
When you save your audio recordings digitally, they are available in a specific format that describes the structure of the file and contains all the audio signals. In general, there are two variants: uncompressed audio formats, which contain all data, and compressed audio formats. With these, certain information is cut from the file. The compressed music formats can also be divided into lossless and lossy formats.
Uncompressed formats include the following, among others:
- PCM (raw data)
- AIFF (Audio Interchange File Fomat)
- CDDA (Compact Disc Digital Audio)
The most important compressed formats are:
- WMA (Windows Media Audio) / WMA lossless
- AAC (Advanced Audio Coding)
- FLAC (Free Lossless Audio Codec)
What defines a lossless format?
Uncompressed audio formats store all audio file data – even data that is barely perceptible to the human ear. This takes up a lot of storage space, but the sound quality is excellent. Lossless files are compressed to a certain extent to reduce file size, but this is done in such a way that no noticeable loss of quality can be detected. All original data is preserved, only the arrangement of the data is changed.
What's a lossy compression format?
One of the best-known lossy formats is MP3. For this format, parts of the original file are removed to reduce storage space. Ideally, you should only remove the file information that is not perceptible to the human ear. The higher the level of compression, the smaller the file, but bear in mind that each further reduction results in a greater loss of quality.
Processing audio files further:
Saving and compressing storage space
The most common uncompressed music formats are WAV and AIFF. If you record audio files with a digital audio workstation, you usually export them in one of these two formats and then process them further. If you want to save the data losslessly at first, but want to preserve the original data, compress the files using an audio program in a lossless format, for example a FLAC file. This takes up less space on the data storage medium, so you can also store a relatively large amount of data on external media and transfer it.
Since all the information is still included in the file and is only unpacked when you open it, you can process these music files in the most optimum way: i.e. cutting, adding effects or additional audio tracks, or splitting the file – all without sacrificing audio quality.
If you want to split your music and audio files, upload them online, send them by email or store multiple files on one data storage medium, you need to compress the files. This can also be done using appropriate audio software, some of which you can download free of charge online. Compression reduces the file size, depending on the extent of the compression. At the same time, information in the audio file that cannot be restored is lost, so take care when compressing.
Bit rates: Defining the quality of an audio file
The bit rate shows how much data in the music file is processed per second. The higher the value, the higher the quality of the file. Uncompressed files usually have a bit rate of 1,411 kilobytes. If you convert a WAV file to MP3 format, you can set the bit rate to 192 or 320 Kb per second.
Overview of various audio formats
Which music format is right for a use scenario and what exactly are the differences in sound? Find out below when to use which format.
Uncompressed formats: PCM, WAV
PCM describes the raw data of an audio file. The format allows for very high bit rates and therefore high audio quality. The format conains the original data and the sound corresponds to that of an audio CD. One thing to note: the PCM format is very memory intensive and can't be played with all standard audio programs, such as those intended for use with MP3 format – so you need special software for processing the raw file.
WAV files are also available uncompressed, i.e. you work with the original data of your recorded music or speech. This format offers a clear, crisp sound quality. WAV files can be played back on many music players. When transferring these files, however, it makes sense to compress them, as the format takes up a lot of disk space.
Compressed, lossless formats: FLAC, WMA Lossless and ALAC
After you have compressed a sound file, it's not possible to recover the information that has been removed. There are therefore some audio formats that are compressed, but still contain all the file information.
One of the most essential compressed and lossless formats is FLAC: The Free Lossless Audio Codec reduces the file size by about half by arranging the data differently, but preserving all the audio information. FLAC is a good choice when you want to share files for further processing. FLACs can be converted to smaller formats such as MP3 without loss. The same applies to the Windows WMA Lossless format and the ALAC format used by Apple. These work on the same principle, but FLAC can be played and further edited on platforms on almost all systems.
Compressed, lossy formats: MP3 etc.
MPEG-1 Audio Layer 3, MP3 for short, is the most widely used audio format and is the format that's made sharing and storing music a matter of course. Here, the data is significantly reduced so that only the essential, audible information remains. In this way, files comprising several hundred megabytes, such as those in WAV format, can be reduced to a few megabytes.
However, MP3 also has disadvantages: The smaller the file, the worse the quality. AAC files can solve this problem. These have a higher quality than MP3 because they work on a more detailed principle in terms of error fixing, and can also be more easily set up with features for digital rights management. For instance, ACC files usually come in a smaller file size than MP3 files and in higher quality. Audio enthusiasts generally prefer this format to other compressed audio files.
WMA is also highly compressed. The process for reducing the size of the audio file is similar to that of MP3 and the quality is also comparable. At low bit rates, however, WMA has the edge, as this type of file can be greatly reduced in size while maintaining high quality.
Quality and storage space
Uncompressed file formats such as WAV contain all file information and can be played back and processed without any loss of quality. Compressed audio formats free up storage space when saving audio files to data storage media and sharing them online. MP3 is the most common compressed format, while ACC offers higher quality.