RF64

RF64 is a BWF-compatible multichannel audio file format enabling file sizes to exceed 4 GiB. It has been specified by the European Broadcasting Union.

The file format is designed to meet the requirements for multichannel sound in broadcasting and audio archiving. It is based on the Microsoft RIFF/WAVE format and Wave Format Extensible for multichannel parameters. Additions are made to the basic specification to allow for more than 4 GB file sizes when needed (the new maximum filesize is now approximately 16 exabytes). The format is transparent to the BWF and all its supplements and chunks. RF64 WAV files typically use the .wav file extension.

RF64 is the basis for ITU recommendation ITU-R BS.2088, which defines a substantially similar standard, BW64, which replaces binary format metadata chunks with extensible XML metadata. EBU Tech 3306 Version 2 (2018) now recommends the use of BW64 format exclusively, to avoid duplication of standards.