Digital audio formats or how sound is stored on a computer

Digital audio formats or how sound is stored on a computer

Digital Audio Formats

Today there are about three dozen common digital audio formats. Why you need to create so many types of sound files to store one type of content and how to manage all this, you will learn from this material.

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Surely many users prefer to use their home computer not only as a workhorse, but also as a multimedia center, where they can watch movies or family photos, as well as listen to their favorite music. Although compact digital players or mobile phones are certainly more suitable for listening to musical compositions, but unlike them, a computer can not only play music.

No matter how big the built-in memory of your music player is, it will most likely be difficult to store your entire music library on it. Plus, you can create, edit, organize, and search for music with your PC. Also, don’t forget that there are around three dozen common digital audio formats today, and most players are far from omnivorous and can only play a few of them.

So why do you need to create so many music formats to store one type of content? The fact is that, in the vast majority of cases, the sound is stored in “compressed” form, since one minute of uncompressed composition occupies about 10 MB on the hard disk. On the one hand, this seems not to be much, but on the other, if you are a music lover and your collection consists of several hundred or even thousands of songs, then it is clear that the sound must be compressed to reduce the space it occupies in electronic media.

Various special algorithms are used to compress music files, which subsequently determine the structure and presentation of the audio data, or so-called digital audio file formats. All audio formats can be divided into three groups: uncompressed audio formats, lossless compression, and lossy compression.

No compression
One of the most widespread formats related to this type is the well-known WAV. The sound of files with this extension is stored without compression or changes. It is true that much more space is required to store uncompressed files and therefore WAV is more widely used only in professional audio and video applications, where the sound should not have a loss of quality before processing. Keeping ordinary musical compositions in this form is unwarranted waste.

To play WAV files, you do not need any special software, as all media players understand this format, including the standard Windows Media audio player built into the Windows system.

Another format used to store uncompressed audio that is worth mentioning is Apple’s development called AIFF (Audio Interchange File Format). As you may have guessed, it is most commonly used on Macintosh computers running Mac OS X.

Lossless compression (lossless)
Lossless compression algorithms for audio files work on the principle of conventional file cabinets. They do not provide the highest level of compression (40 to 60%), while they have virtually no effect on sound quality. It is also worth noting that in this case, the encrypted data can be fully restored to its original form. Therefore, the use of lossless compression is most often used when it is important to keep the compressed data identical to the original.

The most popular audio formats in this group are FLAC (Free Lossless Audio Codec), APE (Monkey’s Audio), WMA (Windows Media Lossless), and ALAC (Apple Lossless Audio Codec). Each has its own pros and cons. For example, the APE codec offers slightly better compression gains, while FLAC is more common. In general, all true music lovers store their music collections in lossless formats, as they do not remove any data from the audio stream and the files created with these codecs can be listened to even on high-quality stereos.

To play lossless compressed formats, as a rule, third-party players (except WMA) are used, such as MPlayer, foobar, AIMP, Winamp, VLC and others, since all the necessary codecs are already built into them. Another option is to separately install an additional codec pack (for example, K-Lite), after which you can listen to files in lossless format from almost any audio player.

Lossy compression
This is the most popular group of algorithms that provides the maximum audio compression ratio (up to 10 times or more). However, unlike previous formats, the audio file loses quality here, and how much depends

Varieties of digital audio formats.

Varieties of digital audio formats.

Audio Formats

There are several concepts of audio format.

Audio Format

The audio data presentation format in digital form depends on the quantization method of a digital-to-analog converter (DAC). The sound equipment at the present time the most common two types of quantization:

Pulse – code modulation
sigma – delta – modulation
Often bit quantization and frequency sampling point for various audio devices that record and play back as digital audio presentation format (24-bit / 192 kHz, 16-bit / 48 kHz).

The file format determines the structure and presentation of the audio characteristics of the data when stored on a PC storage device. To eliminate redundancy of audio data using audio codecs, with the help of which compression of audio data is carried out. There are three groups of audio file formats:

uncompressed audio formats, such as WAV, AIFF
lossless compressed audio formats (APE, FLAC)
audio formats, with the use of lossy compression (mp3, ogg)
There are only modular music format files. By synthetically or sampled pre-recorded live instruments, they are, in the main, used for the creation of modern electronic music (MOD). Also here the format of MIDI can be attributed, which is not a sound recording, but in this with the help of a sequencer it allows to record and play music, using a specific set of commands in the form of text.

Sound digital media formats are used as that of mass-propagated sound recordings (the CD, the SACD), so and in a professional recording (the DAT, MiniDisc).

For surround sound systems and you can select sound formats, in a multi-channel accompaniment largely without sound for movies. Such systems have a set family of two large formats that compete the companies of the Digital Theater then Systems Inc. – DTS and Dolby Laboratories Inc. – Dolby Digital.

Also called format the number of channels in multi-channel sound systems (5. 1; 7. 1). Initially, this system was designed for the cinema, but later it was extended to home theater systems.