The Broadcast Wave File (BWF) specification, EBU Tech 3285 , first saw the light of day in 1997 (BWF version 0). Since that time it has seen steadily increasing acceptance in the professional audio world such that nowadays it is certainly one of the more commonly encountered audio file formats in European broadcasting. Whilst it was updated in 2001 to include an SMPTE UMID (BWF version 1) and although six EBU supplements have appeared, describing various "chunks" that can reside in the file and that bestow enhancements to the basic format, nothing has changed in the specification.
Until now.
EBU R 128 Loudness support
The EBU is pleased to announce that the BWF version 2 specification has just been published. It is still known as EBU Tech 3285, and it still maintains compatibility with versions 0 and 1 and all the chunks designed for the BWF.
The difference is that 10 of the previously reserved bytes are now used to carry information about the file's loudness, which will facilitate the use of the BWF in environments that are compliant with the requirements of EBU Recommendation R 128 .
The backwards compatibility of version 2 with versions 1 and 0 means that software designed to read version 1 and version 0 files will interpret the files correctly except that version 0 software will ignore the UMID and loudness information which may be present and version 1 software will ignore the loudness information.
It is to be hoped that devices in current use will be updated to be BWF version 2 compatible because the loudness and UMID are essential metadata that should be taken into account by modern production, playout and transmission infrastructures.
The loudness metadata fields now incorporated in EBU Tech 3285 will also be appearing in EBU Tech 3306, the specification of the RF64/MBWF file format very shortly too, so be sure that your audio equipment is kept "up to spec."