File Format Guidelines for Management and Long-Term Retention of Electronic records
2.5.1 Broadcast WAVE Format LPCM (.wav)
The Broadcast WAVE format (BWF) with LPCM encoding is a subtype of the WAVE format (Waveform Audio File Format). In 1997, the BWF
format was introduced by the European Broadcast Union (EBU) in 1997 and has since gained widespread use as the preferred archival
format for audio files. Version 0 appeared in 1997, Version 1in 2001, and Version 2 in May 2011. Versions 0 and 1 are very similar, and
Version 2 includes new loudness metadata.
The standard WAVE specification allows for an unlimited number of data ´chunksµ to sit in the head of a WAVE file. A BWF file simply
includes additional metadata in the head of the file, including the EBU’s ´Broadcast Audio Extensionµ chunk, commonly known as the ´bextµ
chunk. The bext chunk allows for important archival metadata to be embedded in the file, including the title of the recording, the recording’s
creator, whether the recording is part of a compilation, and much more. This information tells listeners what they are listening to, identifies
essential preservation information, and allows multi-part recordings (such as multiple tracks) to be played back properly.
The data within a WAVE file is usually encoded with Linear Pulse Code Modulated Audio (LPCM), although it can also contain other variations
of Pulse Code Modulated Audio (such as DPCM or ADPCM) and MPEG-encoded audio. The recommended preservation standard is to use
LPCM. Alternative encodings are rarely used.
Please contact the State Archives for more information about tools to convert simple WAVE files to BWF.
For more technical information about BWF preservation, please see the Federal Agencies Digitization Guidelines
Initiative Audio-Visual Working Group recommendations.
2.5.2 WAVE Format LPCM (.wav)
The Waveform Audio File Format (WAVE) is a standard master format for digital audio. Although it can contain compressed audio, WAVE
files nearly always contain audio in uncompressed linear pulse code modulation format (LPCM).
WAVE files are widely used throughout the commercial and preservation sectors with a standardized set of additional metadata fields
contained within the ´bextµ header chunk (see 2.5.1 Broadcast WAFE Format LPCM (.wav)). WAVE files that do not contain this additional
Federal Agencies Digitization Guidelines Initiative (FADGI), Guidelines: Embedded Metadata in Broadcast WAVE Files,
http://www.digitizationguidelines.gov/guidelines/digitize-embedding.html (accessed 9/7/2012).