WAV - Waveform Audio File Format

WAV is the format Windows has used for raw sound since the early 1990s. Microsoft and IBM defined it together, and its full name is Waveform Audio File Format. The idea was simple: store the audio exactly as a sound card plays it, with no clever compression to unpick first. That makes WAV the plain, dependable option for recording, editing and mastering, and it is still what most audio software writes when you tell it not to compress anything.

How a WAV file stores sound

A WAV file is a RIFF file. RIFF, the Resource Interchange File Format, is a container built from labelled blocks called chunks, each announcing its name and its length. Two chunks matter most. The format chunk states how the audio is encoded: sample rate, bit depth and number of channels. The data chunk is the audio itself, normally uncompressed PCM, which is nothing more than a long list of numbers measuring the waveform many thousands of times a second. Everything else is optional, and a player that does not recognise a chunk can skip it.

Because nothing is compressed, WAV is lossless: what you get back is exactly what went in, and the file size is pure arithmetic. CD-quality stereo runs at 44,100 samples a second, 16 bits each, across two channels, which works out to a little over 10 MB per minute. WAV can also hold compressed audio, such as ADPCM or A-law, by naming a different code in the format chunk, though that is rare today. One real limit comes from RIFF's 32-bit chunk lengths: a WAV file cannot pass 4 GB, which is why very long recordings sometimes arrive as RF64 or Wave64 instead.

What metadata a WAV file carries

WAV metadata is optional, and how much you find depends entirely on what wrote the file. Its classic home is a LIST chunk of INFO entries, again labelled with four characters: INAM (title), IART (artist), IPRD (album or product), ICRD (creation date), IGNR (genre), ICMT (comment), ICOP (copyright), IENG (engineer) and ISFT, the software that made the file. Some programs write an ID3 tag or an XMP packet into a chunk of their own instead, and music software may add cue markers or loop points.

The interesting one is bext, the Broadcast Wave extension used throughout radio, film and television. It records a free-text description, an originator and an originator reference, the origination date and time, a coding history and a time reference that pins the recording to a timecode on set. Field recorders often add an iXML chunk on top, carrying project, scene, take and tape names, the names of the individual tracks, the device model and serial number, and on some recorders the coordinates of where you were standing.

So a WAV report can be revealing. An engineer's name, a studio, a shoot date, a device serial number and a location all live in a normal broadcast WAV without anyone deciding to put them there. A WAV exported by a basic recorder, on the other hand, may have no descriptive metadata at all beyond the format chunk. Both are perfectly valid files, which is why it is worth looking rather than assuming.

When to use WAV

Use WAV while you are working: recording, editing, layering, or handing audio to someone who will process it further. There is no decoding cost, every editor understands it, and no round of edits loses quality. For storage the obvious alternative is FLAC, which is also lossless but meaningfully smaller and much better at holding tags. For sending music to listeners, MP3 or AAC will be a fraction of the size at a quality most people never question. Keep the WAV as your master and make the small files from it.