RF64RIFF64

RF64RIFF64 is an informal designation used to describe a 64-bit RIFF-based container for audio files, most commonly associated with the RF64 extension of the WAV format. RF64 is designed to overcome the 4 GB size limit of traditional RIFF/WAV files by using a 64-bit size field and a dedicated ds64 chunk to store the actual 64-bit file size, data size, and related metadata. In practice, RF64 files follow a RIFF-like structure but begin with an RF64 form type, rather than the classic RIFF form, to signal that 64-bit sizes are in use. The ds64 chunk carries the 64-bit values and may also carry optional fields such as sample counts or cue points.

The term RF64RIFF64 is typically used informally in documentation or vendor discussions to emphasize 64-bit support within a RIFF-based container. It is not widely recognized as an independent standard separate from RF64 itself. The key technical distinction remains that RF64 enables files larger than 4 GB and supports 64-bit data size reporting, whereas RIFF64 as a standalone term is less commonly used in official specifications.

Use cases for RF64/RF64RIFF64 include long-form or multi-channel audio recordings, high-resolution masters, and archival projects where file sizes exceed the traditional RIFF/WAV limit. Compatibility varies: modern DAWs and players with RF64 support can read RF64 files, while older software may fail to recognize the 64-bit structures.

See also: RF64, WAV, RIFF, ds64, RIFF64 (concept).