WAV
Encyclopedia
Waveform Audio File Format (WAVE, or more commonly known as WAV due to its filename extension), (also, but rarely, named, Audio for Windows) is a Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

 and IBM audio file format
Audio file format
An audio file format is a file format for storing digital audio data on a computer system. This data can be stored uncompressed, or compressed to reduce the file size. It can be a raw bitstream, but it is usually a container format or an audio data format with defined storage layer.-Types of...

 standard for storing an audio bitstream on PCs
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

. It is an application of the RIFF bitstream format
Bitstream format
A bitstream format is the format of the data found in some stream of bits used in a digital communication or data storage application. The term typically refers to the format of the output of an encoder or the format of the input to a decoder when using data compression.Standardized...

 method for storing data in "chunks", and thus is also close to the 8SVX
8SVX
8SVX is a subformat of the Interchange File Format. The subformat is for 8-bit sampled sounds, supports both mono and stereo streams as well as loops; commonly used as a basic audio sample format on Amiga computers for many years...

 and the AIFF format used on Amiga
Amiga
The Amiga is a family of personal computers that was sold by Commodore in the 1980s and 1990s. The first model was launched in 1985 as a high-end home computer and became popular for its graphical, audio and multi-tasking abilities...

 and Macintosh computers, respectively. It is the main format used on Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

 systems for raw and typically uncompressed audio. The usual bitstream encoding is the linear pulse-code modulation (LPCM) format.

Description

Both WAVs and AIFFs are compatible with Windows, Macintosh
Macintosh
The Macintosh , or Mac, is a series of several lines of personal computers designed, developed, and marketed by Apple Inc. The first Macintosh was introduced by Apple's then-chairman Steve Jobs on January 24, 1984; it was the first commercially successful personal computer to feature a mouse and a...

, and Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 operating systems. The format takes into account some differences of the Intel CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

 such as little-endian
Endianness
In computing, the term endian or endianness refers to the ordering of individually addressable sub-components within the representation of a larger data item as stored in external memory . Each sub-component in the representation has a unique degree of significance, like the place value of digits...

 byte order. The RIFF format acts as a "wrapper" for various audio compression codec
Codec
A codec is a device or computer program capable of encoding or decoding a digital data stream or signal. The word codec is a portmanteau of "compressor-decompressor" or, more commonly, "coder-decoder"...

s.

Though a WAV file can hold compressed audio, the most common WAV format contains uncompressed audio in the linear pulse code modulation (LPCM) format. The standard audio file format for CD
Compact Disc
The Compact Disc is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage , write-once audio and data storage , rewritable media , Video Compact Discs , Super Video Compact Discs ,...

s, for example, is LPCM-encoded, containing two channels of 44,100 samples per second, 16 bits per sample. Since LPCM uses an uncompressed storage method which keeps all the samples of an audio track, professional users or audio experts may use the WAV format for maximum audio quality. WAV audio can also be edited and manipulated with relative ease using software. The WAV format supports compressed audio, using, on Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

, the Audio Compression Manager. Any ACM codec can be used to compress a WAV file. The user interface
User interface
The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...

 (UI) for Audio Compression Manager may be accessed through various programs that use it, including Sound Recorder in some versions of Windows.

Beginning with Windows 2000
Windows 2000
Windows 2000 is a line of operating systems produced by Microsoft for use on personal computers, business desktops, laptops, and servers. Windows 2000 was released to manufacturing on 15 December 1999 and launched to retail on 17 February 2000. It is the successor to Windows NT 4.0, and is the...

, a WAVE_FORMAT_EXTENSIBLE header was defined which specifies multiple audio channel data
Surround sound
Surround sound encompasses a range of techniques such as for enriching the sound reproduction quality of an audio source with audio channels reproduced via additional, discrete speakers. Surround sound is characterized by a listener location or sweet spot where the audio effects work best, and...

 along with speaker positions, eliminates ambiguity regarding sample types and container sizes in the standard WAV format and supports defining custom extensions to the format chunk.

There are some inconsistencies in the WAV format: for example, 8-bit data is unsigned while 16-bit data is signed, and many chunks duplicate information found in other chunks.

WAV files can contain embedded IFF "lists", which can contain several "sub-chunks".

Metadata

As a derivative of the Resource Interchange File Format (RIFF), WAV files can be tagged with metadata
Metadata
The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...

 in the INFO chunk. In addition, WAV files can embed Extensible Metadata Platform
Extensible Metadata Platform
The Adobe Extensible Metadata Platform is a standard, created by Adobe Systems Inc., for processing and storing standardized and proprietary information relating to the contents of a file....

 (XMP).

Popularity

Uncompressed WAV files are large, so file sharing
File sharing
File sharing is the practice of distributing or providing access to digitally stored information, such as computer programs, multimedia , documents, or electronic books. It may be implemented through a variety of ways...

 of WAV files over the Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

 has declined in popularity. However, it is still a commonly used file type, suitable for retaining "first generation" archived files of high quality, for use on a system where disk space is not a constraint, or in applications such as audio editing, where the time involved in compressing and uncompressing data is a concern.

More frequently, the smaller file sizes of compressed but lossy
Lossy data compression
In information technology, "lossy" compression is a data encoding method that compresses data by discarding some of it. The procedure aims to minimize the amount of data that need to be held, handled, and/or transmitted by a computer...

 formats such as Ogg Vorbis, MP3
MP3
MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...

, ATRAC, AAC
Advanced Audio Coding
Advanced Audio Coding is a standardized, lossy compression and encoding scheme for digital audio. Designed to be the successor of the MP3 format, AAC generally achieves better sound quality than MP3 at similar bit rates....

, Musepack
Musepack
Musepack or MPC is an open source lossy audio codec, specifically optimized for transparent compression of stereo audio at bitrates of 160–180 kbit/s...

 and WMA
Windows Media Audio
Windows Media Audio is an audio data compression technology developed by Microsoft. The name can be used to refer to its audio file format or its audio codecs. It is a proprietary technology that forms part of the Windows Media framework. WMA consists of four distinct codecs...

 are used to store and transfer audio. Their small file sizes allow faster Internet transmission, as well as lower consumption of space on memory media. However, lossy formats trade off smaller file size against loss of audio quality, as all such compression algorithms compromise available signal detail. There are also lossless
Lossless data compression
Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. The term lossless is in contrast to lossy data compression, which only allows an approximation of the original data to be reconstructed, in exchange...

 codec
Codec
A codec is a device or computer program capable of encoding or decoding a digital data stream or signal. The word codec is a portmanteau of "compressor-decompressor" or, more commonly, "coder-decoder"...

s, such as FLAC, Shorten
Shorten
Shorten is a file format used for compressing audio data. It is a form of data compression of files and is used to losslessly compress CD-quality audio files . Shorten is no longer developed and more recent lossless audio codecs such as FLAC, Monkey's Audio , TTA, and WavPack have become more...

, Monkey's Audio
Monkey's Audio
Monkey's Audio is a file format for audio data compression. Being a lossless format, Monkey's Audio does not discard data during the process of encoding, unlike lossy compression methods such as AAC, MP3, Vorbis and Musepack....

, ATRAC Advanced Lossless, Apple Lossless
Apple Lossless
Apple Lossless Apple Lossless Apple Lossless (also known as ALAC (Apple Lossless Audio Codec), or ALE (Apple Lossless Encoder) is an audio codec developed by Apple Inc. for lossless data compression of digital music. After initially being proprietary for many years, in late 2011 Apple open sourced...

, WMA Lossless, TTA
TTA (codec)
True Audio is a free software, real-time lossless audio codec, based on adaptive prognostic filters.Also, .tta is the generic extension to filenames of audio files created by True Audio codec.- Codec overview :...

, and WavPack
WavPack
WavPack is a free, open source lossless audio compression format developed by David Bryant.-Features:WavPack compression can compress 8-, 16-, 24-, and 32-bit fixed-point, and 32-bit floating point audio files in the .WAV file format. It also supports surround sound streams and high frequency...

, but none of these is yet a ubiquitous standard for either professional or home audio.

The usage of the WAV format has more to do with its familiarity, its simplicity and simple structure, which is heavily based on the RIFF file format. Because of this, it continues to enjoy widespread use with a variety of software applications, often functioning as a 'lowest common denominator
Lowest common denominator
In mathematics, the lowest common denominator or least common denominator is the least common multiple of the denominators of a set of vulgar fractions...

' when it comes to exchanging sound files among different programs.

Use by broadcasters

In spite of their large size, uncompressed WAV (though that format can be different from the Microsoft WAV) files are sometimes used by some radio broadcasters, especially those that have adopted the tapeless system. BBC Radio
BBC Radio
BBC Radio is a service of the British Broadcasting Corporation which has operated in the United Kingdom under the terms of a Royal Charter since 1927. For a history of BBC radio prior to 1927 see British Broadcasting Company...

 in the UK uses 44.1 kHz 16-bit two-channel .wav audio as standard in their VCS system. A phased migration to 48 kHz sample rate has been announcedhttp://guidelines.gateway.bbc.co.uk/dq/radio/delivery.shtml. BBC English Regions
BBC English Regions
BBC English Regions is the division of the BBC responsible for local television, radio, web and teletext services in England. It is one of the BBC's four 'Nations' - the others being BBC Scotland, BBC Wales and BBC Northern Ireland....

 already uses 48 kHz.
  • The ABC
    Australian Broadcasting Corporation
    The Australian Broadcasting Corporation, commonly referred to as "the ABC" , is Australia's national public broadcaster...

     "D-Cart" system, which was developed by the Australian broadcaster, uses 48 kHz 16-bit two-channel .wav files, which is identical to that of Digital Audio Tape
    Digital Audio Tape
    Digital Audio Tape is a signal recording and playback medium developed by Sony and introduced in 1987. In appearance it is similar to a compact audio cassette, using 4 mm magnetic tape enclosed in a protective shell, but is roughly half the size at 73 mm × 54 mm × 10.5 mm. As...

    .
  • The Digital Radio Mondiale consortium uses WAV files as an informal standard for transmitter simulation and receiver testing.

Limitations

The WAV format is limited to files that are less than 4 GB
Gigabyte
The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is...

, because of its use of a 32-bit
32-bit
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....

 unsigned integer
Integer
The integers are formed by the natural numbers together with the negatives of the non-zero natural numbers .They are known as Positive and Negative Integers respectively...

 to record the file size header (some programs limit the file size to 2–4 GB). Although this is equivalent to about 6.8 hours of CD-quality audio (44.1 kHz, 16-bit stereo), it is sometimes necessary to exceed this limit, especially when greater sampling rate
Sampling rate
The sampling rate, sample rate, or sampling frequency defines the number of samples per unit of time taken from a continuous signal to make a discrete signal. For time-domain signals, the unit for sampling rate is hertz , sometimes noted as Sa/s...

s or bit resolutions are required. The W64 format was therefore created for use in Sound Forge
Sound Forge
Sony Sound Forge is a digital audio editing suite by Sony Creative Software which is aimed at the professional and semi-professional markets....

. Its 64-bit
64-bit
64-bit is a word size that defines certain classes of computer architecture, buses, memory and CPUs, and by extension the software that runs on them. 64-bit CPUs have existed in supercomputers since the 1970s and in RISC-based workstations and servers since the early 1990s...

 header allows for much longer recording times.
The RF64
RF64
RF64 is a BWF-compatible multichannel file format enabling file sizes to exceed 4 GB. It has been specified by the European Broadcasting Union.The file format is designed to meet the requirements for multichannel sound in broadcasting and audio...

format specified by the European Broadcasting Union
European Broadcasting Union
The European Broadcasting Union is a confederation of 74 broadcasting organisations from 56 countries, and 49 associate broadcasters from a further 25...

 has also been created to solve this problem.

Unlike formats like FLAC
FLAC
FLAC is a codec which allows digital audio to be losslessly compressed such that file size is reduced without any information being lost...

, WAV files don't usually have information fields
Field (computer science)
In computer science, data that has several parts can be divided into fields. Relational databases arrange data as sets of database records, also called rows. Each record consists of several fields; the fields of all records form the columns....

, for instance,
in the case of a song, title, artist, album, year, etc.

Non-audio data

Since the sampling rate of a WAV file can vary from 1 Hz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....

 to 4.3
32-bit
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....

 GHz
GHZ
GHZ or GHz may refer to:# Gigahertz .# Greenberger-Horne-Zeilinger state — a quantum entanglement of three particles.# Galactic Habitable Zone — the region of a galaxy that is favorable to the formation of life....

, and the number of channels can be as high as 65536, .wav files have also been used for non-audio data. LTspice
LTspice
LTspice is a free high performance SPICE III simulator software. LTspice provides a schematic capture and waveform viewer with enhancements and models to speed the simulation of switching regulators...

, for instance, can store multiple circuit trace waveform
Waveform
Waveform means the shape and form of a signal such as a wave moving in a physical medium or an abstract representation.In many cases the medium in which the wave is being propagated does not permit a direct visual image of the form. In these cases, the term 'waveform' refers to the shape of a graph...

s in separate channels, at any appropriate sampling rate, with the full-scale range representing ±1 V
Volt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...

 or A
Ampere
The ampere , often shortened to amp, is the SI unit of electric current and is one of the seven SI base units. It is named after André-Marie Ampère , French mathematician and physicist, considered the father of electrodynamics...

 rather than a sound pressure.

Audio CDs

Audio CDs
Compact Disc
The Compact Disc is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage , write-once audio and data storage , rewritable media , Video Compact Discs , Super Video Compact Discs ,...

 do not use WAV as their sound format, using instead Red Book audio
Red Book (audio CD standard)
Red Book is the standard for audio CDs . It is named after one of the Rainbow Books, a series of books that contain the technical specifications for all CD and CD-ROM formats.The first edition of the Red Book was released in 1980 by Philips and Sony; it was adopted by the Digital Audio Disc...

. The commonality is that both audio CDs and WAV files have the audio data encoded in PCM
Pulse-code modulation
Pulse-code modulation is a method used to digitally represent sampled analog signals. It is the standard form for digital audio in computers and various Blu-ray, Compact Disc and DVD formats, as well as other uses such as digital telephone systems...

. WAV is a data file format for a computer to use that cannot be understood by CD players directly. To record WAV files to an Audio CD the file headers must be stripped and the remaining PCM data written directly to the disc as individual tracks with zero-padding added to match the CD's sector size.
In order for a WAV file to be able to be burned to a CD with most burners it should be in the 44100 Hz, 16-bit stereo format.

WAV file compression codecs compared

As mentioned wav files can be encoded with a variety of codecs to reduce the file size (for example the GSM or MP3
MP3
MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...

 codecs).

This is a reference to compare the monophonic
Monaural
Monaural or monophonic sound reproduction is single-channel. Typically there is only one microphone, one loudspeaker, or channels are fed from a common signal path...

 (not stereophonic) audio quality and compression bitrates of the different codecs available for .wav files including PCM, ADPCM, Microsoft GSM 06.10, CELP, SBC
Smart Bitrate Control
Smart Bitrate Control, commonly referred to as SBC, was a technique for achieving greatly improved video compression efficiency using the DivX 3.11 Alpha video codec or Microsoft's proprietary MPEG4v2 video codec and the Nandub video encoder. SBC relied on two main technologies to achieve this...

, Truespeech
Truespeech
Truespeech is a proprietary audio codec produced by the DSP Group. It is designed for encoding voice data at low bitrates, and to be embedded into DSP chips....

 and MPEG Layer-3.
Format Bitrate 1 Minute = Sample
11,025 Hz 16 bit PCM 176.4 kbit
Kilobit
The kilobit is a multiple of the unit bit for digital information or computer storage. The prefix kilo is defined in the International System of Units as a multiplier of 103 , and therefore,...

/s
1292 KB
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...

11k16bitpcm.wav
08,000 Hz 16 bit PCM 128 kbit/s 0938 KB 8k16bitpcm.wav
11,025 Hz 8 bit PCM 088.2 kbit/s 0646 KB 11k8bitpcm.wav
11,025 Hz µ-Law 088.2 kbit/s 0646 KB 11kulaw.wav
08,000 Hz 8 bit PCM 064 kbit/s 0469 KB 8k8bitpcm.wav
08,000 Hz µ-Law 064 kbit/s 0469 KB 8kulaw.wav
11,025 Hz 4 bit ADPCM 044.1 kbit/s 0323 KB 11kadpcm.wav
08,000 Hz 4 bit ADPCM 032 kbit/s 0234 KB 8kadpcm.wav
11,025 Hz Microsoft GSM 06.10 018 kbit/s 0132 KB 11kgsm.wav
08,000 Hz MP3
MP3
MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...

 16 kbit/s
016 kbit/s 0117 KB 8kmp316.wav
08,000 Hz GSM6.10 013 kbit/s 0103 KB 8kgsm.wav
08,000 Hz Lernout & Hauspie
Lernout & Hauspie
Lernout & Hauspie Speech Products, or L&H, was a leading Belgium-based speech recognition technology company, founded by Jo Lernout and Pol Hauspie, that went bankrupt in 2001...

 SBC 12 kbit/s
012.0 kbit/s 0088 KB 8ksbc12.wav
08,000 Hz DSP Group
DSP Group
DSP Group, Inc. is a provider of chipsets for VoIP, multimedia, and digital cordless applications. Founded in 1987 with headquarters in San Jose, California, DSP Group employs over 400 people at three US sites and offices in Germany, Scotland, Israel, India, Hong Kong and Japan.-History:DSP Group...

 Truespeech
Truespeech
Truespeech is a proprietary audio codec produced by the DSP Group. It is designed for encoding voice data at low bitrates, and to be embedded into DSP chips....

009 kbit/s 0066 KB 8ktruespeech.wav
08,000 Hz Mp3 8 kbit/s 008 kbit/s 0060 KB 8kmp38.wav
08,000 Hz Lernout & Hauspie
Lernout & Hauspie
Lernout & Hauspie Speech Products, or L&H, was a leading Belgium-based speech recognition technology company, founded by Jo Lernout and Pol Hauspie, that went bankrupt in 2001...

 CELP
004.8 kbit/s 0035 KB 8kcelp.wav


The above are WAV files; even those that use the MP3
MP3
MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...

 codec have the ".wav" extension.

See also

  • Audio Compression Manager
  • Broadcast Wave Format (BWF)
  • RF64
    RF64
    RF64 is a BWF-compatible multichannel file format enabling file sizes to exceed 4 GB. It has been specified by the European Broadcasting Union.The file format is designed to meet the requirements for multichannel sound in broadcasting and audio...

    , an extended file format for audio (multichannel file format enabling file sizes to exceed 4 gigabytes)

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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