Digital audio formats or how sound is stored on a computer


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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.

Audio format developments | Digital audio | How to Create Digital Media  Infographics Using ConceptDraw PRO | Audio Infographic

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


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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.

What formats are used to represent digital audio?

What formats are used to represent digital audio?

Audio Formats

The format is used in two different ways.

Digital Audio Formats

When using a specialized medium or recording method and special read / write devices, the concept of format includes both physical characteristics of a sound carrier: the dimensions of a cassette with a magnetic tape or disk, the tape itself, or a disc, recording method, signal parameters, encoding and error protection principles, etc. .P. When using a universal information medium of wide application, for example, a flexible computer or a hard disk, the format is understood only as a method of encoding a digital signal, the peculiarities of the arrangement of bits and words and the structure of service information; all the “low-level” part directly related to working with the media, in this case, remains under the control of the computer and its operating system.

Of the specialized digital audio formats and media, the following are the best known today:

CD (Compact Disc) is a 120mm or 90mm single sided optical laser read / write disc, containing a maximum of 74 minutes of stereo sound at 44.1 kHz sampling rate and 16 linear quantization bits. The system is offered by Sony and Philips and is called CD-DA (Compact Disc – Digital Audio). For error protection, Cross Interleaved Reed-Solomon code (CIRC) and Hamming code 8-14 modulation (Eight to Fourteen Modulation, EFM) are used. A distinction is made between stamped compact discs (CD) write-only (CD-R) and rewritable (CD-RW).
PCM decoder (PCM deck): a system for converting the digital audio signal into a pseudo-video signal compatible with popular video formats (NTSC, PAL / SECAM) and vice versa. PCM decoders are used in combination with home (VHS) or studio (S-VHS, Beta, U-Matic) VCRs, using them as read / write devices. The devices operate with 16-bit linear quantization at sample rates of 44.056 kHz (NTSC) and 44.1 kHz (PAL / SECAM) and can record a two- or four-channel digital signal. In fact, such a decoder is a modem (modulator-demodulator) for a video signal.
S-DAT (Fixed Head Digital Audio Tape – Fixed Head Digital Audio Tape) is a system similar to a conventional cassette recorder, in which recording and reading is performed by a block of thin film fixed heads in a 3.81 mm wide tape in a double-sided cassette with dimensions of 86 x 55.5 x 9.5 mm. It implements two- or four-channel 16-bit recording at 32, 44.1, and 48 kHz.
R-DAT (Rotating Head Digital Audio Tape) is a VCR-like system with cross-tilted rotating head recording. The most popular tape-based digital recording format, R-DAT systems are often referred to simply as DAT. The R-DAT uses a 73 x 54 x 10.5mm cassette, with a 3.81mm wide tape, and the cassette and tape system itself is very similar to a typical VCR. The basic belt speed is 8.15mm / s, the rotation speed of the main unit is 2000rpm. R-DAT operates with a two-channel signal (on some models, four channels) at sample rates of 44.1 and 48 kHz with 16-bit linear quantization and 32 kHz with 12-bit non-linear quantization. To guard against errors, a double Reed-Solomon code and modulation with an 8-10 code are used. Cassette capacity – 80. .240 minutes depending on speed and belt length. Domestic DAT recorders are usually equipped with a phonogram illegal copy protection system, which does not allow recording from the analog input at a frequency of 44.1 kHz, as well as direct digital copying in the presence of SCMS prohibition codes (Serial Code Managenent System). Studio tape recorders have no such restrictions.
DASH (Digital Audio Stationary Head) is a 6.3 and 12.7 mm wide magnetic tape recording system with fixed heads. Belt speed is 19.05, 38.1, 76.2 cm / sec. Implements 16-bit recording with sample rates of 44.056, 44.1 and 48 kHz from 2 to 48 channels.
ADAT (Alesis DAT) is a proprietary system for recording eight-channel audio on S-VHS videotape, developed by Alesis. It uses linear quantization of 16 bits at 48 kHz, the capacity of the cassette is up to 60 minutes per channel. ADAT tape recorders can be cascaded so that a 128-channel synchronous recording system can be assembled.

Digital audio file formats wav, mp3, aiff, ogg, flac, m4a

Digital audio file formats wav, mp3, aiff, ogg, flac, m4a

digital audio formats

The last five years gave a great boost to the development of portable and stationary audio systems, and with this support for a variety of digital audio formats.

DIGITAL AUDIO FORMATS

Small pocket devices have a large internal memory and fixed audio equipment has become even smarter and more demanding. That is why, now, we can not save space on the player and download songs that weigh between 15 and 30 MB each, but at home, listen to digital music in a quality equal to the sound of an analog vinyl.

Description of popular digital audio formats
However, the most widespread audio formats still have their pros and cons, and even in an urgent matter like digital audio, a “panacea” has not yet been found. Classic digital audio formats are divided into “compressed” and “uncompressed” streams, as well as “lossless” formats, which exclude loss of sound.

Description of digital audio formats Description of digital audio formats

Wav audio format
The waveform audio file format (WAVE, WAV – “in waveform”) is a file format for storing a recording of an uncompressed digitized audio sequence. In general, this is the most common format for working in the studio and in broadcasting. allows you to get the most honest sound quality. For example, the standard audio CD format is an LPCM audio stream, with parameters: 2ch (stereo), 44-100Hz, 16bit.

Mp3 audio format
MPEG-1/2 Audio Layer 3: (MP3) is the most popular digital format for storing compressed audio. The MP3 format uses a special algorithm designed to greatly reduce the size of the original file. This format allows you to keep the audio close to the original sound, but thanks to a variety of settings, extremely small size.
Compared to the standard audio CD format, a file in MP3 format and a bit rate of 128 kbps will be approximately 1/11 the size of the original file.

FLAC audio format
FLAC (Free Lossless Audio Codec) is a popular free codec designed for lossless compression of audio data. What does that mean? Unlike lossy audio codecs such as MP3 or OGG, the FLAC audio codec does not remove any information from the audio stream. This format is ideal for audiophiles who create their own music collections and listen to music on high-quality equipment.

Ogg audio format
OGG is a format that has not gained great popularity, but is nonetheless used by a fairly large audience. The OGG format, similar to MP3, compresses audio with loss of quality, but is fundamentally different in practical conversions. This made it possible to get better quality with a smaller file size and to display this codec as absolutely independent. In addition to similar formats that convert lossy audio, OGG has the ability to adjust container properties.

Aiff audio format
The Audio Interchange File Format (AIFF) is a fairly universal audio file format developed by Apple, which is used to store audio data. Like its counterpart, the WAV format, it is uncompressed audio and is widely used in professional recordings and music production.
The .aiff and .aif files created by Apple Loops are used by GarageBand and Logic Audio music editors.

M4a audio format
Apple Losseles (also known as Apple Lossless Encoder, ALE or Apple Lossless Audio Codec, ALAC) (m4a) is another Apple development. This audio format refers to uncompressed audio, which provides lossless playback. It is a fairly specific format, which is mainly supported by products of the creator company, and in some cases, as in the iPhone system sounds, where it is possible to use exclusively the m4a format.

What are digital audio formats

What are digital audio formats

Digital audio formats are basically containers. And the differences between them are fundamentally in:

Whether or not they are compressed.

If they are compressed, in the quality of compression.

The type of labeling they can support.
Digital audio formats

MP3

It is the best known, popular and most widely used. They are known by their “.mp3” extension.

It was developed by Moving Picture Experts Group, so that it was part of the well-known MPEG-1 and MPEG-2 standards.

Its fundamental characteristic resides in the fact that the technology behind it performs a compression of the sound sequence, resulting in a really small file, which normally occupies half of the original file. To achieve this, the loss of certain sounds is necessary, which supposedly cannot be heard by the human ear.

Audio formats

WAV

Developed by the Microsoft and IBM companies, this format, whose name comes from the acronym WAVE (Waveform Aujdio File Format), is currently one of the audio formats that do not have compression in the data, therefore they present an excellent quality.

They are known by their “.wav” extension.

On the other hand, this format has the peculiarity that it includes support for almost all current audio codecs. This makes WAV one of the most widely used formats in the field of professional sound, since the sound is captured with parameters of 44100 Hz and at 16 bits, the same quality can be obtained as on a CD.

On the contrary, one of the disadvantages of this format is that it has a limitation in recording, since it can only capture a maximum of 6.6 hours in the same file at maximum quality.

Audio formats

AIFF

The AIFF (Audio Interchange File Format) format is very similar to WAV. It was born as an answer from Apple to Microsoft’s WAV, being initially only compatible with MAC computers. Currently it can also be used in Windows.

Due to its characteristics, AIFF, together with FLAC and WAV, are usually the most widely used formats in the professional field of audio.

WMA

The WMA (Windows Media Audio) format is a music file format created by Microsoft.

One of its main characteristics is that those files that have been compressed in WMA format take up less space than MP3 files, which also implies a reduction in their quality. Therefore, it is a lossy audio compression format.

OGG

OGG audio formats are compressed audio files, which means that they have a size that allows them to be transmitted via WIFI, but at the same time they avoid the damages that are usually generated in the compression process.

For example, Spotify uses these OGG formats.

Audio formats

FLAC

When we talk about the FLAC (Free Lossless Audio Codec) format, we are referring to a codec free of audio compression and without loss of quality.

Emerged within the community responsible for the OGG project, FLAC has become one of the WAV format’s strongest competitors, due to its advantages in terms of sound quality.

Its objective is to reduce the size of the original file, eliminating data that is usually known as “waste”, without causing loss of quality.

This is the format used by the Tidal platform, the best high quality audio streaming service.

What is the difference between the different audio formats, and which should I choose?

What is the difference between the different audio formats, and which should I choose?

Lossless formats: WAV, AIFF, FLAC, Apple Lossless and others

In summary, there are two types of sound quality: lossless and lossy. Lossless music preserves the sound quality of the original source – in most cases, CD – intact, on the other hand, lossy music compresses the file to save space (in exchange for decreasing quality). Lossless formats include the following formats:

WAV and AIFF: Both are uncompressed formats, making them exact copies of the original sound source. The two formats are essentially the same quality; they simply store the data differently. AIFF was created by Apple – you will see it often in its products – but WAV is much more universal. However, since they are not compressed, they take up too much unnecessary space. Unless you are editing sound, we do not need to use this format.

FLAC: Free Lossless Audio Codec (FLAC). It is the most used lossless codec, it is a good option if we want to store our music without losing quality. Unlike WAV and AIFF, it uses compression, taking up less space. However, it is still a lossless format, which means that the sound quality is the same as the original source, so it is better for listening than WAV and AIFF. It is also free and free software, which is useful if you like to take a look at how it works.

-Lossless Apple (Apple Lossless): Also known as ALAC, it is similar to FLAC. It uses compression, although it is made by Apple. Its compression is not as efficient as that of FLAC, so the files will be slightly larger, but it is compatible with iTunes and iOS (FLAC not). Therefore, if you use iTunes or iOS as the main software for listening to music, you should choose this format.

APE: It is a very high lossless compression file, which means you will save more space. The quality is the same as FLAC, ALAC and other lossless files, but it is not compatible with most players. On the other hand, it makes the processor work more to decode because it is so compressed. Generally, I would not recommend using this format unless you are very concerned about space and have a compatible player.

Lossy formats: MP3, AAC, OGG and more

For day to day, we are more likely to use lossy formats. They save significantly more space, and if they have a high enough bitrate, it will be very difficult to distinguish the quality of the original source. The most commonly used formats are shown below:

MP3: MPEG Audio Layer III, or MP3 for short, is the most common lossy format. So much so that it has become synonymous with music downloads on the internet. It is not the most efficient f-format of all, but it is certainly the most compatible, making this the first choice of lossy sounds.

AAC: Advanced Audio Coding, also known as AAC, is similar to MP3, although slightly more efficient. Which means that the files take up less space and with the same sound quality as MP3. And, with Apple’s iTunes making it so popular, it’s as compatible as MP3.

Ogg Vorbis: The Vorbis format, often known as Ogg Vorbis due to the use of the Ogg container, is the free software version to MP3 and

AAC. Its main attraction is that it is not restricted by patents, but that does not affect you as a user – in fact, despite being open it is of similar quality, and much less popular than MP3 and AAC, so not all players support it. . I do not recommend it unless you are interested in being open source.

WMA: Windows Media Audio. Microsoft’s proprietary format, similar to MP3 or AAC. It really doesn’t offer any advantage over other formats, and it’s not very well supported.

So which one should you use?

Now that we have seen the differences between each format, which one should we use for our music? In general, we recommend using MP3 or AAC. They are compatible with most players, and the quality of both is very similar to that of the original source if encoded with a high bitrate. Unless you have specific needs, MP3 and AAc are the most recommended options.

However, there is something to be said for storing music in lossless formats like FLAC. Although we probably won’t notice higher quality, it is good for storing music if you plan to convert it to other formats later – as converting from one lossy format to another. Lossy (eg from AAC to MP3) will produce lower quality files.