Everything you need to know about audio formats.


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Everything you need to know about audio formats.

Audio Fomats

Whether you use iTunes or buy and download digital music, you will find a number of terms and abbreviations that describe digital audio files. This alphabet soup can be quite confusing. What are audio file formats or codecs? What is the bit rate and what is the sample rate? What does it mean when the music is “high definition”?

AUDIO FORMAT FILES

This article explains what you need to know about digital audio files. I’ll tell you the difference between lossy and lossless files, explain why bitrate matters (or not), and help you understand the various file formats you can encounter.

Compression: lossy and lossless
When you buy a CD, the audio on the disc is not compressed. You can rip (or import) CDs with iTunes or other software, converting CD audio into digital audio files for use on a computer or portable device. In iTunes, you can copy in two uncompressed formats: WAV and AIFF (other software supports other formats). Both formats simply encapsulate the PCM (Pulse Code Modulation) data stored on CD so that it can be read as audio files on a computer, and their bit rate (you’ll find the one below) is 1411 kbps.

WAV and AIFF files can be quite large. Therefore, digital audio files are compressed to save space. There are two types of compression: lossless and lossy. Lossless includes formats (or codecs for short codec algorithms) such as Apple Lossless and FLAC (Free Lossless Audio Codec). Lossy includes the ubiquitous MP3 and AAC formats. (AAC, which stands for Advanced Audio Coding, is actually MP4, the successor to the old MP3. Although Apple adopted it in the early days of iTunes, Apple was not involved in its creation and does not own the format.)

You can also view other audio formats, although they are less common. These include Ogg Vorbis, Monkey’s Audio, Shorten, and others. Some of these codecs are lossy and some are not. However, if you use iTunes and Apple hardware, you will only find WAV, AIFF, MP3, AAC, and Apple Lossless, at least for music.

iTunes can copy or import audio files in these formats. Select the one you want to use in iTunes> Preferences> General> Import Settings.

When you copy or convert an uncompressed audio file to a lossless format and then play that file back, it is a perfect copy of the original (provided the data was read correctly from the CD). Thus, you can convert from one lossless format to another without quality loss.

However, when you copy to a lossy format, if you later convert the file to another format, it loses some of its quality. This is similar to how a photocopy of a photocopy does not look as good as the original.

Some people prefer lossless formats because they play audio like CDs. Lossy compression is a tradeoff to save space, allowing you to store more music on your portable device or hard drive and speed up downloads. However, most people cannot tell the difference between a CD and a lossy file at high data rates, so if you’re ripping your music to sync to iPhone, lossless files are superfluous.

Lossless ripping is a good way to back up your files as you can convert them to other formats without losing quality. And you can have iTunes automatically convert them to AAC files when syncing. Check out this article for more information on this automatic conversion, as well as other lossless file questions.

Bit rates
The best way to measure the quality of an audio file, relative to its original quality rather than its musical or engineering quality, is to look at its bitrate. The bit rate of audio files is measured in thousands of bits per second or kbps. I mentioned earlier that the CD contains 1411kbps audio, and when you convert that audio into a lossy file, its bitrate is much lower.

The higher the bit rate the better, so a 256 kbps MP3 or AAC file is better than a 128 kbps file. However, this is not the case for lossless files. Lossless file transfer speed depends on the density and volume of your music. Two lossless tracks on the same album can have bit rates of, say, 400 kbps and 900 kbps, but when played back, they reproduce the original CD audio at the same level of quality. Lossless compression uses as many bits as necessary and no more.


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Audio file formats

It all starts with Pulse Code Modulation (PCM), the basis for digital audio, which was founded in 1937 and is characterized by two properties: sampling rate for measuring the waveform amplitude and bit depth for measuring possible digital values.

Examples of digital formats for audio sampling are:

– WAV (waveform audio file format)

– MP3, AAC, WMA, Vorbis

– FLAC (Free Lossless Audio Codec) ALAC (Apple Lossless Audio Codec) and APE

WAV:

The same format is used to record audio CDs. Different qualities are available (8-16 bit, 11 to 44 kHz). The higher the quality, the greater the memory usage.

MP3, AAC:

The files. MP3 and AAC are the most common formats when you need to store music on a computer or phone, and exchange or download music on the network and on the Internet. MP3 is a “lossy” format that loses some audio quality to achieve a significant increase in file size. An MP3 has a size of approximately 1 MB per minute.
The difference to lossless formats is that if you convert the file to a less compressed format like WAV, the quality sacrificed during compression will not be restored. For lossy formats such as MP3, the audio quality is measured using the bit rate value, which is generally specified in “192 kbit / s” or “192 kbit / s”.
The higher the bit rate, the more detailed the sound becomes.

FLAC, ALAC, APE:

These formats compress audio using algorithms.
The difference between compressed files and FLAC is that FLAC is specifically designed for audio and therefore has better compression rates without data loss.
As a rule, a .FLAC takes up half of the storage space of a WAV in megabytes and maintains the “CD quality”.
A FLAC can be converted to WAV without loss of quality and is the preferred format for those who want to listen to music with the best quality and great speakers.

Is the audio quality subjective?

In theory no, but in practice it’s very subjective.
To hear real differences between the quality of an audio CD and an MP3 file, you need to use high-end headphones or speakers.
In addition, it also depends on what you are listening to and what type of music, in different formats, can have significant or almost no differences in listening.
If you are looking for the best compromise between file size and quality, you should experiment with the different formats and test whether you have a better experience with MP3 with higher bit rates or even with the playback of FLAC files.

Most important audio formats

Most important audio formats

MP3

MPEG Audio Layer III
-Compressed digital format with loss.
-Its compression size: 11 to 1
-Compresses the audio using a lossy algorithm to obtain a smaller size, decoding the signal, allowing less bits to be consumed, which translates into less weight and less quality.
-Extension: .MP3
-Good compatibility. Can be played on almost all audio players
-Easily distributable online
-Better quality-space ratio
-Loss of the original sound, implies a decrease in quality throughout the format
-Supports two channels
-Distortion in frequency bands where the brightness and sparkle (5000hz-20000hz) are located.
-Increase in the bass and subwoofer frequencies (250hz – 40hz) due to the dynamic compression of the sound that causes a different equalization from the original recording.
-present patterns between tracks

AAC

Advanced Audio Coding
– Lossy compressed digital format
-It is an audio compression system developed by the Fraunhoffer Institute, AT&T, Sony and Dolby Laboratories.
– It is an audio broadband coding algorithm with higher performance than MP3.
-Extension: .m4a, .m4b, .m4p, .m4v, .m4r, .3gp, .mp4, .aac
-Play files from the hard disk of a computer with a quality that can be similar to the CD using significantly less space than an mp3.
-This system increases the quality of the mp3.
-Loss of original sound
-Subject to patent

WAV

Waveform audio format
-Uncompressed digital format.
– Windows own format
– Used to store sounds on PC, supports mono and stereo files at various resolutions and sampling rates
– Extension is .wav
-High sound quality
-Provides faithful listening to the audio
-It works in Windows applications and in common equipment with a CD player.

– Includes support for almost all current audio codecs
– Compatible to convert into various formats by means of the appropriate software.Example switching from Wav to Mp3
-It takes up a lot of disk space
-Poor quality-space ratio
-Difficult to distribute online due to the weight of the file
-Allows to capture in the same file up to 6 hours

FLAC

Free Lossless Audio Codec
– Lossless compressed format

-Extension: .flac
-Higher quality in high fidelity equipment
-Information is continuous between separate tracks
-It does not delete information from the original content
-It is an open source format.
-Code and decode quickly
-It takes up a lot of disk space
-It is not supported by all portable players

AIFF

Audio Interchange File Format
-Uncompressed format without loss.
– Format typical of native applications of Mac OS X for example iTunes
-Extension: .aiff or .aif.
-High sound quality
-Requires large storage space

OGG VORBIS

-Compressed format loss
– Stream-oriented container, which means that
can be written and read in one step, making it suitable
for streaming on the internet.
– Free software version to MP3 and AAC.
– Intended to allow maximum encoder flexibility
Extension: .ogg
-It is free, open and not patented
-Similar to MP3
-Good value for space
-Improved same-size MP3 quality.
-It is not supported by all players
-Loss of original sound

WMA

Windows Media Audio
– Lossy audio compression format, although there is a more recent lossless development
-Windows version to compress audio
-Extension: .wma
-Ideal for real-time streaming
-Reduce size of large files
– Inclusion of support in Windows Media Player
-Lower quality
-It takes space
Real Audio
-Media player with various functions and Internet connection tools
Example: listening to music and watching videos hosted on the Internet (streaming), and creating and playing extensive playlists.

– Ideal for live streaming over the network due to its streming ability
– the coding allows adapting it to the user’s reception capacity depending on their internet connection speed.
-Can be used in different operating systems (Windows, Linux, Mac OS)
– Ability to transfer files to other multimedia devices
-Reduction in file sizes

-Incompatibility with some browsers
-High RAM consumption

APE

– Lossless compressed format
-Extension: .ape
-Save space
-High quality
-Better file compression rate
-It is not compatible with most players.
-Slow to compress and decompress files

Understanding digital audio formats

Understanding digital audio formats

When it comes to digitally distributing our music it is important that we understand what they are
the different formats, which are the most used and which are the best in terms of the
Relationship between size and quality.

PCM digital audio

WAVE

The name comes from the acronym waveform audio file format and is a used file
usually on computers with the Windows operating system.
WAV or WAVE files contain audio in LPCM format (Linear Pulse Code
Modulation) This is a way to encode an analog audio signal to the domain
digital by using equidistant samples over time of amplitude values
of the analog signal.
The quantity of samples is given by the sampling rate or sampling rate,
while the amount of possible amplitude values ​​is determined by the
Bit depth or bit rate.
The sampling frequency of the CDAUDIO for example is 44.1 kHz and 16 bits. exist
higher sampling rates such as 48 kHz, 88.2 kHz, 96 kHz up to 192 kHz at
this system.
On the other hand, WAV files are uncompressed audio and are generally used in
stages of recording, editing, mixing and mastering for being of high quality.
The higher the sample rate and the greater the number of bits, the file size will be
our hard drive
In general for professional uses at least a frequency of
44.1 kHz sampling and a depth of 24 bits preferably.
The standard extension for this type of file is: .wav

AIFF

The name comes from Audio Interchange File Format or audio file format
interchangeable, this format was developed by Apple computers and is used to save
and manipulate audio on computers.
It is like WAV a file type without compression or lossles therefore allows
Processing for professional applications such as recording, editing, mixing and
mastering as well as for professional video uses.
Another similarity with WAV files is that it is PCM audio (press code
modulation) that for practical purposes it is the same as the LPCM.
The standard extension for this type of files is .aiff

MP3

Also known as MPEG1 or MPEG2 audio layer, it is a form of coding
of digital audio in which psychoacoustic models discard information from
Audio that is presumed is not audible to most users.
As an example a file created with a resolution of 128 kbits / s is equivalent to 1/11
the size of a file on an audio CD.
The main purpose of using this type of coding is to reduce the size of the
files and be able to send / download faster, especially through
from Internet.
Being a file type reduced in quality IS NOT RECOMMENDED for
recordings, editing, mixing or mastering of professional audio.
For this reason we recommend NOT to use it to send us your clues to
mix / master