Broadcast Wave Format (wav)

Broadcast Wave Format was developed by an EBU Project Group (see The Broadcast Wave Format – an Introduction) to provide a product-independent means of exchanging programme material between workstations from different manufacturers. It is based on the Microsoft WAVE audio file format (file extension .wav), which is one of a number of file types specified in the Microsoft Resource Interchange File Format (RIFF). A BWF file is a type of RIFF file which contains audio data.

NOTE: Confusion exists over the naming of audio file extensions, and clarification is not assisted by web sites which refer to BWAV files. File extensions written as .bwf or .bwav are invalid.

BWF File Parts

Mono
Mono describes a file which has a single, monophonic, track.

Poly
Poly files have more than one track e.g. stereo or multitrack.

Chunks
A “chunk” is a self contained collection of data in a RIFF file. A chunk contains a header, which gives its type and length, followed by data arranged in fixed or variable length fields.

bext
The “Broadcast extension” chunk, which is part of all BWF files. It contains the minimum information expected to be needed by all applications in broadcast production. It contains information on the title, origination, date, time, etc. of the audio content.

mext
An additional chunk in a BWF file containing MPEG audio data.