WAVWAV WAV Waveform Audio File Format (WAVE, or WAV due to its filename extension; pronounced "wave") is an audio file format standard, developed by IBM and Microsoft, for storing an audio bitstream on PCs. It is the main format used on Microsoft Windows systems for uncompressed audio. The usual bitstream encoding is the linear pulse-code modulation (LPCM) format. WAV is an application of the Resource Interchange File Format (RIFF) bitstream format method for storing data in "chunks", and thus is similar to the 8SVX and the AIFF format used on Amiga and Macintosh computers, respectively. Description. The WAV file is  an instance of a Resource Interchange File Format (RIFF) defined by IBM and Microsoft. The RIFF format acts as a "wrapper" for various audio coding formats. Though a WAV file can contain compressed audio, the most common WAV audio format is uncompressed audio in the linear pulse-code modulation (LPCM) format. LPCM is also the standard audio coding format for audio CDs, which store two-channel LPCM audio sampled at 44,100 Hz with 16 bits per sample. Since LPCM is uncompressed and retains all of the samples of an audio track, professional users or audio experts may use the WAV  format with LPCM audio for maximum audio quality. WAV files can also be edited and manipulated with relative ease using software. The WAV format supports compressed audio using, on Microsoft Windows, the Audio Compression Manager (ACM). Any ACM codec can be used to compress a WAV file. The user interface (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, a codice_1 header was defined which specifies multiple audio channel data 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. Specification. RIFF. A RIFF file is a tagged file format. It has a specific container format (a "chunk") that includes a four-character tag (FourCC) and the size (number of bytes) of the chunk. The tag specifies how the data within the chunk should be interpreted, and there are several standard FourCC tags. Tags consisting of all  capital letters are reserved tags. The outermost chunk of a RIFF file has a codice_2 form tag; the first four bytes of chunk data are a FourCC that specify the form type and are followed by a sequence of subchunks. In the case of a WAV file, those four bytes are the FourCC codice_3. The remainder of the RIFF data is a sequence of chunks describing the audio information. The advantage of a tagged file format is that the format can be extended later without confusing existing file readers. The rule for a RIFF (or WAV) reader is that it  should ignore any tagged chunk that it does not recognize. The reader won't be able to use the new information, but the reader should not be confused. The specification for RIFF files includes the definition of an codice_4 chunk. The chunk may include information such as the title of the work, the author, the creation date, and copyright information. Although the codice_4 chunk was defined in version 1.0, the chunk was not referenced in the formal specification of a WAV file. If the chunk were present in the file, then a reader should know how to interpret it, but  many readers had trouble. Some readers would abort when they encountered the chunk, some readers would process the chunk if it were the first chunk in the RIFF form, and other readers would process it if it followed all of the expected waveform data. Consequently, the safest thing to do from an interchange standpoint was to omit the codice_4 chunk and other extensions and send a lowest-common-denominator file. There are other INFO chunk placement problems. RIFF files were expected to be used in international environments, so there is codice_7 chunk to specify the country code, language, dialect, and  code page for the strings in a RIFF file. For example, specifying an appropriate codice_7 chunk should allow the strings in an codice_4 chunk (and other chunks throughout the RIFF file) to be interpreted as Cyrillic or Japanese characters. RIFF also defines a codice_10 chunk whose contents are uninteresting. The chunk allows a chunk to be deleted by just changing its FourCC. The chunk could also be used to reserve some space for future edits so the file could be modified without being rewritten. A later definition of RIFF introduced a similar codice_11 chunk. RIFF WAVE. The toplevel definition of  a WAV file is: The definition shows a toplevel RIFF form with the codice_3 tag. It is followed by a mandatory codice_13 format chunk that describes the format of the sample data that follows. The format chunk includes information such as the sample encoding, number of bits per channel, the number of channels, the sample rate. The WAV specification includes some optional features. The optional fact chunk reports the number of samples for some compressed coding schemes. The cue point (codice_14) chunk identifies some significant sample numbers in the wave file. The playlist chunk allows the samples to be played  out of order or repeated rather than just from beginning to end. The associated data list allows labels and notes (codice_15 and codice_16) to be attached to cue points; text annotation (codice_17) may be given for a group of samples (e.g., caption information). Finally, the mandatory wave data chunk contains the actual samples (in the specified format). Note that the WAV file definition does not show where an codice_4 chunk should be placed. It is also silent about the placement of a codice_7 chunk (which specifies the character set used). The RIFF specification attempts to be a formal specification, but  its formalism lacks the precision seen in other tagged formats. For example, the RIFF specification does not clearly distinguish between a set of subchunks and an ordered sequence of subchunks. The RIFF form chunk suggests it should be a sequence container. The specification suggests a LIST chunk is also a sequence: "A LIST chunk contains a list, or ordered sequence, of subchunks." However, the specification does not give a formal specification of the codice_4 chunk; an example codice_4 LIST chunk ignores the chunk sequence implied in the codice_4 description. The LIST chunk definition for codice_23 does use the LIST chunk  as a sequence container with good formal semantics. The WAV specification allows for not only a single, contiguous, array of audio samples, but also discrete blocks of samples and silence that are played in order. Most WAV files use a single array of data. The specification for the sample data is confused: These productions are confused. Apparently codice_24 (undefined) and codice_25 (defined but not referenced) should be identical. Even if that problem is fixed, the productions then allow a codice_26 to contain a recursive codice_23 (which implies data interpretation problems). The specification should have been something like: to avoid the  recursion. WAV files can contain embedded IFF "lists", which can contain several "sub-chunks". Metadata. As a derivative of RIFF, WAV files can be tagged with metadata in the INFO chunk. In addition, WAV files can embed any kind of metadata, including but not limited to Extensible Metadata Platform (XMP) data or ID3 tags in extra chunks. Applications may not handle this extra information or may expect to see it in a particular place. Although the RIFF specification requires that applications ignore chunks they do not recognize, some applications are confused by additional chunks. Popularity. Uncompressed WAV files are large , so file sharing of WAV files over the Internet is uncommon except among video, music and audio professionals where the uncompressed form has become the most popular of all audio formats and, for most, high speed large bandwidth web connections are commonplace. Many audio and music software manufacturers now favour it as their default file format though others are often supported. The high resolution of the format makes it 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, and the losses in quality of such conversions are a concern. Use by broadcasters. In spite of their large size, uncompressed WAV files are used by most radio broadcasters, especially those that have adopted a tapeless system. Limitations. The WAV format is limited to files that are less than 4 GiB, because of its use of a 32-bit unsigned integer to record the file size header. 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 rates, bit resolutions or channel count are required. The W64 format was therefore created for use in Sound Forge. Its 64-bit header allows for much longer recording times. The RF64 format specified by the European Broadcasting Union has also been created to solve this problem. Non-audio data. Since the sampling rate of a WAV file can vary from 1 Hz to 4.3 GHz, and the number of channels can be as high as 65535, .wav files have also been used for non-audio data. LTspice, for instance, can store multiple circuit trace waveforms in separate  channels, at any appropriate sampling rate, with the full-scale range representing ±1 V or A rather than a sound pressure. Audio CDs. Audio CDs do not use the WAV file format, using instead Red Book audio. The commonality is that audio CDs are encoded as uncompressed PCM, which is one of the formats supported by WAV. WAV is a file format for a computer to use that cannot be understood by most CD players directly. To record WAV files to an Audio CD the file headers must be stripped, the contents must be transcoded if not already stored  as PCM, and the PCM data written directly to the disc as individual tracks with zero-padding added to match the CD's sector size. In order for PCM audio to be able to be burned to a CD, it should be in the 44100 Hz, 16-bit stereo format. Comparison of coding schemes. Audio in WAV files can be encoded in a variety of audio coding formats, such as GSM or MP3, to reduce the file size. This is a reference to compare the monophonic (not stereophonic) audio quality and compression bitrates of audio coding formats available for WAV  files including PCM, ADPCM, Microsoft GSM 06.10, CELP, SBC, Truespeech and MPEG Layer-3. These are the default ACM codecs that come with Windows. The above are WAV files; even those that use MP3 compression have the codice_28 extension. WAV Waveform Audio File Format (WAVE, or WAV due to its filename extension; pronounced "wave") is an audio file format standard, developed by IBM and Microsoft, for storing an audio bitstream on PCs. It is the main format used on Microsoft Windows systems for uncompressed audio. The usual bitstream encoding is the linear pulse-code modulation (LPCM) format. WAV is an application