Description of the main audio formats. Audio file formats

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Description of the main audio formats. Audio file formats

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 in cases where it is important to preserve the identity of the compressed data with respect 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, since they do not remove any data from the audio stream and files created with these codecs can be listened to even on high-quality stereos.

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Frequently asked questions about audio formats

Frequently asked questions about audio formats

The rapid development of computer technology and the Internet has led to the need to create digital formats that could be stored and reproduced on computers without the use of any physical medium. As a result, various types of digital audio formats have been developed.

Types of digital audio formats
All digital audio formats can be divided into 3 groups according to the principle (codec) used to compress audio data, namely:

Lossy formats
These are audio formats that use a lossy compression method for audio data. That is, when encoding a digital audio recording with any of the lossy codecs, certain changes are made to the audio data. This can significantly reduce the size of the resulting file, but at the same time leads to a deterioration in sound quality. The most popular lossy formats include MP3, WMA, Ogg Vorbis, AAC, and others.

Advantages and disadvantages of lossy audio formats
The main advantage of lossy formats is the small file size, while maintaining acceptable quality for listening. Furthermore, these audio formats are compatible with the vast majority of electronic devices and music players, including home audio systems, radio recorders, and MP3 players.

The main drawback is the loss of sound quality compared to the original. If you convert an audio recording from an original licensed audio CD to a lossy format, when you play the resulting file, the sound will be worse than that of the source.

Lossy formats sound bad?
No way. First, when lossy encoding, there is a choice of compression ratio and sound quality. For example, if we are talking about the MP3 format, then to record a voice (audiobooks, audio tracks for a textbook in a foreign language), the CBR 128 kbps quality will be enough, but for music, the ideal option is CBR 320 kbps. It is worth noting that CBR is short for ConstantBit Rate, which stands for Constant Bitrate.

Second, the compression process uses the principle of removing from the recording those frequencies and sounds that a person cannot hear by nature. There is an opinion, confirmed by many experiments, that music compositions in high quality MP3 format (CBR 320 kbps) cannot be distinguished by ear from the original recording or from a licensed audio CD purchased from a store.

Lossless audio format
This is a type of digital audio format in which the audio data is encoded without loss of quality. The sound will not differ from the source in any way, be it a licensed music CD (CDA format) or a digitized vinyl head, saved in uncompressed WAV format (for Windows) or its analog AIFF (for iOS). The most popular lossless formats are FLAC, Monkey’s Audio, ALAC, WavPack, MWA Lossless.

This makes lossless audio formats ideal for listening to music on good audio equipment. For example, in high-end home speakers or Hi-Fi systems and high-end headphones.

Advantages and disadvantages of lossless formats
The main advantage of lossless audio formats is that during encoding and decoding, the program does not remove any data from the audio stream. Because of this, when playing such files, the listener receives the original sound without disturbance.
But lossless audio formats also have a major drawback. The fact is that many devices for playing sound files do not yet support these formats. You can solve the problem by purchasing the right type of equipment, for example a portable Hi-Fi player or a media player, as well as a home audio system that supports lossless audio formats.

Main digital audio formats

Main digital audio formats

–MP3: was created by Moving Pictures Experts Group (MPEG), which created and continues to create standards for storing and transmitting audio and video in digital format. In its entirety, the format is called: MPEG-1 / MPEG-2 Layer 3 (MP3). It is the most popular music storage format in the world today.

MP3 simultaneously compresses data and processes audio to obtain the smallest possible file size. The bit rate can vary from 8 Kb / s to 320 Kb / s, the sampling rate from 16 kHz to 48 kHz. The goal of processing the original recording with the MP3 compression algorithm is to compress the information as little as possible. So if in its original form a song occupies around 70 MB of memory, then in MP3 format with acceptable quality it will only take around 7-8 MB, as you can see, the gain is significant, although it is achieved by degrading the sound quality .

–AAC: The format has become popular because Apple has adopted it as a standard for storing, selling and distributing music in its ecosystem and iTunes. AAC is very similar to MP3 in terms of audio processing during encoding, although it gives a slightly better result.
Furthermore, AAC not only compresses the data, but also performs sound processing, removing a certain type of data, thus achieving significant savings in memory for storing music. The bit rate can range from 8 kbps to 320 kbps, the sample rate ranges from 8 kHz to 96 kHz. With more sophisticated and sophisticated encoding and compression algorithms, AAC music can sound better than MP3 and take up less memory. Another advantage of the AAC format is that it supports up to 48 channels, while MP3 only supports 2.

–WMA: format developed by Microsoft to compete with MP3. During encoding, data is compressed, music is processed, and parts of it are removed, saving memory. However, there is a variation of the format called WMA Lossless that preserves the quality of the original sound. The vast majority of modern phones, players and computers support this format and there should be no problems with its playback. However, some computers may have a hard time playing them, so if you want maximum compatibility, MP3 may be worth choosing.

–FLAC: Developed by the Xiph.Org organization, this format is free for any type of use, so it is quite widespread these days.
FLAC uses data compression, however it preserves the original sound quality of the recording. music is not processed. The recording quality can be 32-bit / 96 kHz (this is significantly higher than the recording quality of CDs, which is 16-bit / 44.1 kHz). The data compression algorithm can save up to 30% memory compared to the original recording, while maintaining perfect sound quality. It is for this reason that the FLAC format has become very common.

–ALAC: this format is analogous to FLAC, but made by Apple, whose full name is Apple Lossless Audio Codec. Its properties are the same as those of FLAC, but its advantage was that all Apple devices could work with it without the need to install third-party applications. Since iOS 11, the FLAC format has also become fully compatible with Apple devices, so the urgent need for ALAC has decreased significantly for the sake of freedom and the greater compatibility with other devices that FLAC offers.

–WAV: A format developed by Microsoft, this format stores the sound in its original form, so the files take up a lot of memory, although they preserve the perfect quality of the music.
WAV does not compress or process sound, we can say that it is an ideal format for storing master copies and for subsequent sound processing. Although there are certain encoding settings that allow you to compress data, they are generally not used. WAV files are similar in storage method to PCM and AIFF formats.

–AIFF: a format also developed by Apple, the full name is Audio Interchange File Format. The main goal is to store music on Apple computers in its original form.
AIFF doesn’t compress data or perform any sound processing, so like WAV it takes up a lot of memory. The best sound storage format if you want to keep processing it in an editor or convert it to other formats on Mac computers.

–PCM: This format is used for digital recording of analog signals, which is sound. It is a standard for recording audio to CDs, but can also be used to store music digitally in computer memory. PCM does not compress audio, ideal for storing master copies of music or for professional audio work.

How are audio file formats different and what does this mean for listeners?

How are audio file formats different and what does this mean for listeners?

Music File Formats

Explanation of MP3, AAC, WMA, FLAC, ALAC, WAV, AIFF and PCM

audio file formats

Most devices are capable of playing a wide variety of digital media formats out of the box, often without the need for software or firmware updates. If you flip through the product guide, you might be surprised how many different types there are.

What makes them different from each other? Should it be important to you?

Music file formats
When it comes to digital music, does the format really matter? Answer: it depends.

There are compressed and uncompressed audio files that may or may not have quality loss. Lossless files can be huge in size, but if you have enough storage space (such as a PC or laptop, network drive, media server, etc.) and have high-quality audio hardware, there are advantages to using without compress or lossless sound,

But if there isn’t enough space, like on smartphones, tablets, and portable players, or if you plan to use basic headphones or speakers, then all you need are smaller compressed files.

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So how do you choose? Here is a breakdown of common format types, some of their important features, and the reasons why you should use them.

-MP3: Developed by the Moving Picture Experts Group (MPEG), an organization that develops standards for encoded video and audio programs, MPEG-1 / MPEG-2 Layer 3 (MP3) is perhaps the most common type of audio file and compatible.
MP3 is a lossy and compressed audio format with a bit rate ranging from 8 kbps to a maximum of 320 kbps and a sampling frequency of 16 kHz to a maximum of 48 kHz. Smaller MP3 file sizes mean faster file transfers and less space used, but at the cost of slightly lower audio quality than lossless file formats.
-AAC: Popular on Apple iTunes, Advanced Audio Coding (AAC) is similar to MP3, but has an added benefit:
-AAC is a lossy compressed audio and audio format, with bit rates ranging from 8 kbps to a maximum of 320 kbps, and sampling rates from 8 kHz to a maximum, with the correct encoding process, 96 kHz.
AAC files can offer the same audio quality as MP3 and take up less space. ACC also supports up to 48 channels, while most MP3 files can only handle two. AAC is widely compatible with, among others, iOS, Android, and portable gaming devices.
-WMA. Developed by Microsoft as a competitor to MP3, Windows Media Audio files offer similar but proprietary capabilities. Standard WMA is a lossy and compressed audio format, although newer standalone versions with more advanced codecs may offer a lossless option.
While many types of portable and home entertainment media players support WMA files by default, only some mobile devices, such as smartphones and tablets, support it. Many require downloading a compatible application to play WMA audio, which can make it less convenient than MP3 or AAC.
-FLAC. Developed by the Xiph.Org Foundation, the free lossless audio codec (FLAC) is very attractive due to its free license and open format.
-FLAC is a lossless, compressed audio format with file quality up to 32-bit / 96 kHz (for comparison, CD is 16-bit / 44.1 kHz). FLAC has the advantage of a reduced file size (approximately 30-40 percent smaller than the original data) without the need to sacrifice sound quality, making it ideal for digital archiving (that is, using it as master copy to create compressed / lost files for general listening).
-ALAC: Apple’s version of FLAC, Apple Lossless Audio Codec (ALAC), shares FLAC in terms of sound quality and file size.
-ALAC is a lossless compressed audio format. It is also fully compatible with iOS and iTunes devices, although FLAC may not be supported. As such, ALAC is the most used by those who use Apple products.
-WAV: Waveform audio file format, also developed by Microsoft, is a standard for Windows-based systems and is compatible with various software applications.

Audio formats

Audio formats

The audio format is a type of computer file that contains music. There are lossless uncompressed, lossless compressed and lossy music audio formats.

Bit rates
Bit rate is a unit of measurement for data that indicates the number of bits transmitted in a given time. When it comes to music formats, the bit rate is expressed in kilobits per second (kbps) transmitted. If you compare the same song encoded at different bit rates, the file with the highest bit rate will be of higher quality. For example, a 320 kbps (CBR) MP3 file transmits 320 kilobits for every second of the audio stream.

Audio formats containing uncompressed lossless data (Uncompressed Lossless)
Lossless uncompressed data formats retain all original recorded information. Since silence is encoded at the same number of bits per second as sound, files containing uncompressed lossless data are often large. Formats containing lossless and uncompressed data are encoded using pulse code modulation (PCM). Examples:

WAV (PCM) (used in Windows)
AIFF (PCM) (used in Mac OS).
Audio formats containing lossless compressed data (Compressed Lossless)
Lossless compressed formats store all original recorded information in a smaller volume than uncompressed lossless data when compressing data. Silence is encoded at the lowest bit rate and audio is compressed, so files that contain lossless compressed data are usually half the size (file size) of the same song in a format that contains non-data. uncompressed loss.

Since formats that contain compressed data without loss of quality and formats that contain uncompressed data without loss of quality both retain all the information from the original recording, they can be transcoded to each other without loss of quality. Examples:

Free Lossless Audio Codec (FLAC)
Apple Lossless Audio Codec (ALAC)
Mono Audio (APE).
Lossy audio formats
Lossy formats always compress data. Lossy audio formats are smaller than those that contain lossless compressed data and formats that contain uncompressed lossless data by removing some of the original information. These are usually high frequencies that most people cannot hear, however in some cases the difference in lossy and lossless audio formats can be very large.

Since lossy formats lose data during compression (and therefore sound quality), they CANNOT be transcoded to lossless or other lossy audio formats without further loss of sound quality. Examples:

MPEG Layer 3 Audio (MP3)
Advanced Audio Coding (AAC)
Windows Media Audio (WMA)
Dolby Digital 3 (AC3) audio codec
DTS Coherent Acoustics Codec (DTS).
File sizes
Here we can see how the file size of the same song depends on the format in which it is presented: uncompressed data without loss of quality, compressed data without loss of quality or loss of quality. Take Avril Lavigne’s classic pop song Sk8er Boi for example. The song is 3 minutes and 24 seconds long.

Lossless uncompressed format – WAV (PCM): 34.3 MB
Lossless compressed format – FLAC: 25.75 MB (25% compression)
Lossy format – MP3 320 (CBR): 7.78 MB (78% compression)
Sound transparency
Sound transparency is a term used to describe the sound characteristic of a lossy file. The sound of a lossy file is considered transparent if the average person cannot hear the difference between it and a lossless file with the same song, having listened to both files and not knowing in what sequence they were heard. For most people, MP3 192kbps (CBR) is considered transparent.

Allowed audio formats
While there are many types of lossy and lossless audio formats, only a few are allowed on RED.

Since some lossless audio formats can be transcoded to other lossless audio formats without loss of audio quality, the only lossless audio format allowed on RED is FLAC. You can always download FLAC and transcode it to ALAC (for iTunes) or any other lossless or lossy audio format you want.

Allowed lossy audio formats:

MP3 (the minimum bit rate for MP3 is 192 kbps (CBR))
AAC (can be replaced by any MP3 torrent except downloads purchased from the iTunes store and containing exclusive tracks from iTunes)
AC3 (usually found on DVD)
DTS (usually found on DVD)
MP3 is the most popular audio format on RED. We allow you to upload albums to AAC purchased from iTunes because they often contain bonus tracks from iTunes, and since AAC is a lossy format, it cannot be transcoded to other audio formats without losing sound quality. Also, AC3 and DTS are often found on DVD and are lossy audio formats, so they cannot be transcoded to other audio formats without losing sound quality.

Comparison of audio formats

What is the best audio format for what purpose?

Comparison of audio formats

All radio and podcast producers are faced with the question: What audio format is best for my shows and contributions? There is usually no simple answer. Each file format and each codec has advantages and disadvantages.

Audio Formats Comparison

Before converting / converting, you need to be clear about what you plan to do with your audio file: Should it be published to the NRWision media library? Is the program designed to broadcast on the Internet or for the home audio system? Should the file be edited again if necessary? Only then can you weigh which audio format and which properties make the most sense.

Audio File Formats comparision

Compress without loss?

You must decide whether you want the best possible sound quality or the smallest possible file size. With some audio codecs, sound is retained at its full bandwidth and without loss. Other codecs compress the file so that it takes up less space or is faster to transfer online. At best, it can still be played on many different devices and players. Depending on the strength of the compression, the sound of music or voice recording may also be audibly affected.

In the case of audio files, information such as sample rate and bit rate always play a role.

The sample rate indicates how often the level is saved per second. CDs, for example, have a sample rate of 44,100 Hz. 44,100 values are stored for one second of music.

Bit transfer rate

Bit rate defines the amount of data that is processed per second. It can be constant or variable and therefore also influences the sound quality.
Important: When converting audio files to other formats, the quality cannot be improved, it only deteriorates or is preserved. With each compression, some of the audio data is lost, although it is not necessarily audible.

Next we present the audio formats and their properties.

MP3

File extension: .mp3

MP3 is probably the most popular and widely used audio format in the world. It became the standard for music files on the Internet more than 20 years ago and has been freely available since 2017. By the way, MP3 was developed by the Fraunhofer Institute in Germany, among others. Raw audio is highly compressed when converted to MP3 files to save storage space. Only what humans can hear should be preserved. You can set the degree of compression, the so-called bit rate. 192 kBit / s (kilobits per second) roughly corresponds to CD quality. At higher bit rates, MP3 files sound lossless to most people. Lower bit rates are used, for example, in Internet radios.

Advantage:
widely used, compatible with many playback devices, high compression

Disadvantage:
possibly loss of audible quality, especially at low bit rates

Wav

File extension: .wav

WAV files are not compressed and therefore take up a lot of storage space. But they can be used well for audio editing and can be easily edited in almost any software.

WAV files were developed for Windows computers in 1991. However, they can also be reproduced and used on other operating systems.

Advantage:
no need to encode / decode when editing

Disadvantage:
very large files

WMA

File extension: .wma

Originally, the WMA (Windows Media Audio) format was supposed to compete with MP3, but it could not be established equally. Audio data is also compressed here, if possible without audible loss.

Some versions of WMA files may contain a certificate key to prevent piracy.

Advantage:
good compression with high sound quality

Disadvantages:
not very widespread, only supported by a few players

AAC (advanced audio coding)

File extension: .aac

This audio format is considered the successor to the MP3 format. With the AAC format, developers have managed to further reduce memory size while maintaining the best possible sound quality.

The AAC process is being used with increasing frequency on music websites, Internet radio stations, and as a soundtrack format for video files.

Advantage:
very good compression, small files with high audio quality

Disadvantage:
not yet compatible with all programs and devices

Ogg

File extension: .ogg

In Ogg files, there is actually a container format. In addition to compressed audio, it can also contain video and text data. Also, Ogg files can be used well as an online stream. Even so, the format never prevailed against MP3 among home users.

Advantage:
small file size with good sound quality, no license

Disadvantage:
not compatible with many programs, must be converted for audio processing

FLAC (Free Lossless Audio Codec)

File extension: .flac

The name already gives it away: the FLAC codec is freely available and compresses audio files without loss of quality. The format is mainly used for music that can be faithfully reproduced thanks to FLAC. More and more players support FLAC files, sometimes just with the help of a plugin.

The FLAC codec makes audio files 30 to 60 percent smaller. This makes them much larger than MP3 files. To do this, you can decode it and thus restore the original data without loss.

Advantage:
no loss, no license

Disadvantage:
relatively large files, not natively supported by all players

Opus

File extension: .opus

The latest file format from our overview should become the Internet audio standard. Opus is developed openly and has several advantages. The audio codec significantly reduces the bit rate again. The quality of music and language is preserved as best as possible. Additionally, Opus files can be streamed and contain metadata.

Opus plays practically no role (yet) in audio processing. We are curious to see if and how the format will prevail for years to come.

Audio formats

Before you know the audio formats, know that they are divided into two main groups: the compressed and the uncompressed.

Uncompressed formats are those in which the audio quality is assessed and without loss of information, which guarantees that the audios are practically identical to the real ones. Tablets reduce the original file size, taking up less space on your computer or cell phone memory. However, the quality and information may be compromised.

It is worth mentioning that it is not just a good format that guarantees that the end result will be of excellent sound quality. You need to do your part, too, using good audio software to make the necessary changes and “cleanup,” as well as using quality equipment to record your voice.

1. Advanced Audio Coding (AAC)

It is considered the main competitor to the most famous format on the Internet, MP3, and is commonly used on Apple devices, based on the MPEG-4 standard.

Compared to MP3, AAC has more flexibility, which means you will experience less data loss and quality when compressed. Also, it has a better level at lower bit rates, such as 128 kbps.

2. OGG Vorbis

This is a non-proprietary format, that is, they have no restrictions for audio players to play it. Also, it has a better compression rate than MP3, however it is not as well known or advertised.

It is widely used in game audio, because among other qualities, it brings open source, which provides greater customization, but is difficult to standardize. Its audio quality is quite satisfactory.

3. MP3

Considered the most popular audio format in the world, MP3 offers high compatibility, allowing music and audio to be played in virtually any program or media player.

It was created in Germany and uses the so-called perceptual encoding, which encodes only the sounds that humans can hear. Of all, it manages to be the most balanced in terms of quality versus size.

It may get to lower bit rates, but there may be a final quality loss.

4. WMA

This is Microsoft’s standard format and also quite popular. Unlike MP3, WMA allows the creation of content-protected copies, thus preventing your music or other audio productions from being pirated.

Microsoft’s proposal is that the format achieve a sound property equivalent to that of MP3, but in a much smaller size. In practice, this does not happen, but at low bit rates the result is very similar.

It offers four codecs:

Standard WMA: acts as an MP3 repeater;
WMA Pro: guarantees higher definition audio;
WMA Lossless: allows file compression without loss of quality;
WMA Voice – Aimed at low bit rate voice recordings.

5. MP2

Although it already has a successor, MP2 is still widely used, being the standard format for transmitting radio and television audio. It is a file extension for MPEG -1 layer II playback (MP3 plays in MPEG -1/2 layer III).

One of the attributes of the MP2 is that it still has great compatibility, as well as fewer errors than its successor. In addition to having better performance in audios with higher bit rates.

6. Real Audio

RealNetworks proprietary format. They have multiple audio codecs and great performance for those with low bit rates. It was constantly used in dial-up modems, hi-fi formats for music and streaming, as is the case with web radio.

RealNetworks is an internet provider that works with streaming services. It was founded by a former Microsoft executive and also offers entertainment services through subscriptions.

7. Audio Coding 3 (AC3)

Created in 1983 by Dolby Laboratories, AC3 is primarily used in DVDs, Blu-ray players, home theaters, and HDTV playback. It can reproduce frequencies between 20 and 20,000 Hz, which is equivalent to the human audible sound.

Therefore, the AC3 can reproduce unique and detailed sounds, with very good quality. Its bit rate goes up to 640kpbs and its display speed goes up to 48kHz.

8. WAV

One of the best characteristics of this format is that it has a high sound fidelity rate, that is, it faithfully reproduces what was recorded without compression or loss of data.

It is widely used by those who work with audio editing, since it will be able to manipulate the real sound and without any interference. It is also considered for those who need more definition and sound fidelity as possible for their productions.

Mp3, the winner

In the era of broadband connections, fiber optics and HD videos on YouTube, MP3 remains the reference format for audio files. We are now so used to listening to music in compressed formats, and often through poor quality playback systems, that it is difficult for us to remember what listening to music really means. The recent evolution from download to hit-and-run streaming has only made the situation worse by further devaluing the value of music. When was the last time you listened to a record from start to finish without interruption, spending those 30-40 minutes on “simple” listening activity?

Premise: This post is not a crusade against Spotify because I use it myself for new releases or to have some background music at work, it is not even an analog vs. digital (or vinyl vs. CD vs. MP3) post because on this topic en Much has already been said. My goal is to make you understand what you are missing, in qualitative terms, if you listen to music in compressed formats.

Sampling and theoretical aspects.

Audio recording on a computer or digital medium assumes that the signal passes through an analog> digital (AD) converter, so that the continuous electrical signal generated by microphones or musical instruments is transformed into a digital signal (series of 0 and 1) This process is called sampling. The final quality of the recording depends on several factors: converter quality, sample rate, and bit depth.

To make an easily understandable comparison: When shooting a movie, the “analog” reality perceived by our eye is stored in a movie that takes 24 frames per second. If we consider the standard of the audio CD (44.1 kHz, 16 bits), for every second of music 44100 pictures are taken from the computer to the continuous electrical signal. If with the sampling frequency we have simply established how many times in a second the waveform will be analyzed, with the bit depth we assign to each sample a numerical value: 2 ^ 16 = 65,536 possible values.

If you wonder how it got to 44,100, I refer you to the Nyquist-Shannon sampling theorem.

When we press the record button on our computer, through the PCM (pulse code modulation) sampling process described above, the files are saved in uncompressed WAV or AIFF format.

Lossless files and lossy files

PCM files take up a lot of space on our hard drives because, as we have seen, there is the data necessary to describe the analog waveform in as much detail as possible. Indicatively, a WAV or AIFF file as audio CD will occupy 10 MB for every minute of music.

To overcome this problem, remember that in the early 2000s storage space cost around $ 10 / GB, while today the price is around $ 0.03 / GB (source): Audio formats have been introduced that , through an algorithm encodes and decodes information, reduces the size of the file. These codecs fall into two categories: formats with lossless compression and formats with lossy compression.

As the name implies, lossless compression indicates a reduction in file weight (usually around 50%) without loss of information. Leaving the world of audio aside for a second, ZIP and RAR files are clear examples of this type of compression: at any time we can “unzip” such a file and have access to the original information again without this no way has changed.

The most common file formats are: FLAC (Free Lossless Audio Codec) and ALAC (Apple Lossless Audio Codec).

Lossy compression, on the other hand, implies that some of the original audio information is somehow removed to obtain a file that weighs even 90% less than the PCM.

By what criteria is information removed without “compromising” the original audio too much? Since our hearing is an imperfect instrument, codecs exploit two principles of psychoacoustics: the minimum threshold of audibility (the human ear does not perceive all frequencies in the range between 20Hz and 20kHZ equally) and masking (a weaker sound). is masked, making it inaudible, by a louder sound.)

Compression algorithms, however advanced, introduce a number of artifacts into audio files that, if played back in discrete quality audio systems, can be easily recognized or at least noticed even by an inexperienced ear. Several studies have shown that an untrained ear does not distinguish the difference between an uncompressed file and an MP3 with a bit rate equal to 256kb / s or more.

The most common lossy formats are: MP3, OGG Vorbis, AAC.

The victory of MP3

Since its introduction in the mid-1990s, MP3 has established itself as the industry-standard consumer format fueled by file-sharing through peer-to-peer channels, where, with slow connections, the heaviest file was the one it was downloaded, the longer it took to obtain it, and since the market introduction of MP3 players in which we tried to store as much music as possible and, therefore, we resorted to very compressed files.

In the transition from the era of downloading to that of small transmission files, they ensure smoother and smoother data transmission.

Despite, therefore, the evolution that has taken place in recent years in the speed of Internet connections and the reduction in the price of storage systems, only in recent years have services been created to buy files from High-quality online audio (HD tracks) or HD streaming services (Tidal).

Examples and audio files.

The main services we use to buy or listen to music use these compression levels (all information is taken from the official websites of each service at the time this publication was written).

Spotify: OGG Vorbis files at 96 kb / s (normal mobile quality), 160 kb / s (normal desktop and web player quality, high mobile quality), 320 kb / s (premium users: high desktop quality, very high quality mobile).
iTunes: By default, CDs are imported into 128 kb / s AAC files. Files in the iTunes Store are of this quality, except for “iTunes Plus” songs converted to AAC at 256 kb / s.
Pandora: 64kb / s AAC (free users), 192kb / s AAC (premium users).
YouTube: HD videos (720 or 1080p) have an audio quality equal to 384kb / s, SD videos (360, 480p) have an audio quality equal to 128kb / s.

Choose the sound format well into 2020

Although many dematerialized music rhymes with MP3, it is recommended to take a tour of the owner in existing dematerialized formats to choose the audio format well when digitizing their CD / Vinyl.

What is an audio format?

An audio format is to simplify a kind of container where dematerialized music is stored: it is important to choose it carefully when ripping a CD, because its properties will directly affect the quality of the file created.

Therefore, selecting audio format is a crucial step and it is advisable to guarantee three things with priority: the quality, functionality, and the fact that they are standard and legible on a maximum of devices, whether on a PC or MAC computer, but also on your smartphone / car radio …

It is also important to understand that in general, and although there are exceptions, the choice of audio format consists of placing the cursor in the middle between the quality on the one hand and the space occupied by the media on the other. storage.

Choose audio format: which challengers?

select aac-ogg-wma mp3 audio format
The 4 semi-amazing audio formats with destructive compression.

MP3:
Give glory where honor is due. MP3 is just as popular as it is underrated: it will have done a lot for dematerialized music by itself and has enabled millions of people around the world to discover a new way to listen to their music.

MP3 is a format of strong and destructive compression, in other words, a large part of the musical signal will be suppressed (priority, frequencies inaudible to the human ear … but not only!), And therefore offers a quality that only becomes good for from 256/320 kbps.

Is this a good opportunity today? Not being the best from a quality standpoint, choosing mp3 audio format today allows you to be sure that you can listen to it on all devices released for 10 years. MP3 is dematerialized music, what jeans should wear: versatility and the highest “acceptance rate” in the world.

Note that it is also advisable to choose mp3 audio format if you have limited storage space on a smartphone, for example because it is (in the company of AAC / WMA / OGG) the type of format that requires least space.

AAC:
This format is similar to “Apple MP3”. It has the same qualities and shortcomings as the previous one with some details: slightly better at the same speed, on the other hand it is far less standard: except for the fact that manufacturers have made explicit agreements (and pay because they require a license) , we find in Practice much fewer AAC compliant devices.

So it should be avoided unless you only have Apple products around you (even the car radio? I doubt it) and even in this case they are all perfectly mp3 compatible.

WMA
If AAC is Apple’s MP3, WMA Microsoft is MP3. Even less widespread because it doesn’t benefit from iTunes / Music Store / iPOD steamroller (who still remembers Zune’s iPod killer? Miscrosoft)

Again, forget the same qualities and shortcomings as MP3, but even less standard, therefore urgent. I even advise you to convert your existing WMA files to MP3 at a similar or slightly higher bit rate to ensure durability. Therefore, choosing WMA audio format today is not a good idea.

OGG:
We also find it under the name “vorbis”, we also have an mp3 clone here, except it is compatible with the free world (understand free) a bit in the same format as Linux.

Ogg is a completely free format unlike the previous ones, but despite this it is very confidential and is generally used only by those who take a pro-free dogmatic stance. While this position is quite respectable, selecting OGG audio format in 2014/2015 does not seem like a good idea because it is not widely distributed and above all it is like MP3, a destructive format.

WAV:
WAV is the first format on the list that does not deteriorate the quality extracted from the CD, and therefore offers an identical bit rate of 1411 kbps and therefore provides optimal quality.

However, the format shows its age and is limited in several ways: no space optimization (one second of silence = one second of noise) and no metadata or album cover management.

Therefore, choosing Wav audio format is similar to generating very heavy files and simply impossible to organize properly in a music database.

An overview of the main audio formats that can be found on your computer

Codec for mp3, mpc, flac, mono, ogg vorbis and more.

For convenience, audio formats can be divided into unprofitable (unprofitable) and unprofitable (or unprofitable without losing quality).

The idea of loss formats (most common among ordinary users) stems from the idea that the human ear misunderstands all the sounds that are in a standard WAV file at 44,100 samples per second.

In this way (as in the JPG format of the images) we will drop the high frequencies, which are thought to be less different from our hearing. The more these frequencies are reduced, the more space is allocated to our track (for example, 3 MB instead of 6 MB for a few minutes of song or much more) … but it also degrades the quality of the result, as the cut frequencies are no longer so “inaudible”.

Converting to WAV from lossy formats does not provide any benefit (unless you have to process the track and save it several times, in which case the quality loss will be limited to the first step); There are also programs that are able to bring some of these high frequencies back into our tracks, such as Steinberg Clean Plus or others (such as the first versions of Easy CD Creator or other, even more professional ones), but by doing the job properly , more than No they can do a lot.

Unbearable (lossy) formats try to reduce the space occupied by the track without touching the sound; the degree of compression will be much less than the loss, but there will be no loss of quality. If it is converted back to WAV (possibly processed), the sound will be identical to the previous one.

To listen to audio tracks in various formats, we recommend using audio players that can support different formats, such as AIMP and Foobar2000.

Lost audio formats (lossy quality)

WMA (.wma): Windows Media audio format, compressed and very similar to mp3. Microsoft audio compression format. Files compressed in this format are approximately 20% smaller than MP3 files

MP3 (.mp3) is briefly suitable for the MPEG 1 III layer and identifies audio files that use this algorithm. This is a standard that removes inaudible sounds from the human ear. This way the 128 kbps mp3 track takes up 1/11 of its space in .wav or audio CD format.
Some rate 128-bit bits as “CD quality”; In fact, the frequencies that are reduced to save hard disk space are not so “inaudible”. 192 The results are starting to get good and at only 320 kbps we can talk about the quality of CDs … Until a few years ago the quality of mp3 was considered high, but now with the advent of more modern sound cards, 24 bits: we continue to use mp3 compared to other formats like like ogg or mpc, more for its diffusion and compatibility than the quality of the result. A 600 MB album in wav format will take up about 50 MB in 128 mp3 format.

To convert an audio track to mp3, it’s a good idea to use the Lame mp3 codec (free) in all the best conversion programs (download).

AAC (.aac and .mp4): A lossy format that delivers high quality (currently the highest among lossy formats), at least one step higher than mp3. A feature of this format is the ability to protect DRM from being freely copied from one platform to another (unless applications are used to protect it).

AC3 (ac3). This is the audio format used by DVDs. We usually find it at 384 kbps (and 6 channels), but it is also possible that you only have it at 2 channels and lower speeds. One of the free programs that supports it (and allows, for example, to reduce the bit rate) is BeLight (Besweet).

OGG VORBIS (.ogg) is a great open source codec. It is able to give better results than mp3, especially at low bit rates (higher quality, less space), which is less than 128 kbps (download). It is compatible with virtually all audio players (both software and audio).

MusePack (.mpc): Very large output format, especially at high bit rates (more than 192 kbps and above). The results are much better than mp3: just listen to one 192 kbps mp3 encoded track and one mpc track at the same bit rate to immediately feel the difference (in some cases without words …). Many people considered this to be the best lossy audio format, at least until mp4 was released. It is compatible with WinAmp through plug-ins and, on average, with more advanced players such as Foobar 2000.