What is an RF64 file?
The RF64 file format is engineered to overcome a critical limitation in digital audio: the 4 GB file size ceiling. Primarily designed as a multichannel audio format, RF64 removes this restriction, enabling users to store and work with broadcast-quality audio files that exceed 4GB. This format stores its audio data within a RIFF64 structure in the Broadcast Wave Format (BWF), ensuring full compatibility with the professional BWF standard. A key feature of RF64 is its integration of rich metadata alongside the core sound data, which facilitates seamless exchange and interoperability across different platforms and software applications. Notably, within the Winamp multimedia player for Microsoft Windows, this format is identified and labeled as “RIFF64 broadcast wave,” highlighting its role within that specific playback ecosystem.
Moreover, RF64 is an open format allowing users to broadcast large files, document their activities, and supports timecode to enable synchronization with other recordings. Using the RF64 extension you can easily create Broadcast Wave Files which will contain the “bext” chunk from the BWF specification
RF64 File Format
RF64 can store stereo downmix channels and bitstream data that was not encoded in PCM. This file format can be used throughout the entire workflow, from recording to editing and playback of material, and for long-term or short-term archiving.
Since CUE chunk definitions are inconsistently used, LABL chunk names need to be included in an additional chunk, and CUE chunk pointer indexes are restricted to 32 bits, the 2009 RF64 format also defines an additional ‘r64m’ marker chunk.
As the RF64 file format evolves, it is likely to meet the long-term requirements of broadcasting and archiving. It requires a relatively small amount of software implementation work and will require reasonable changes in existing systems.
Brief History
The European Broadcasting Union developed the RF64 file format, a multichannel audio format that is compatible with BWF. It is based on Microsoft RIFF/WAV format and Wave Format Extensible for multichannel purposes. It has also been accepted as the ITU recommendation ITU-R
Key Characteristics of RA Files
| Characteristic | Description |
|---|---|
| File Extension | .ra64 |
| Format Type | Sample Bank Metadata Archive (Audio Container) |
| Primary Codec | References to external audio samples (e.g., .wav) with embedded mapping data |
| Primary Developer | Roland Corporation |
| Primary Use Case | Organization and transfer of multi-sample instrument libraries for compatible Roland hardware and software. |
| Status | Non-embedded; contains metadata, triggers, and loop points that reference separate audio files. |
Format Specifications
A new ‘ds64’ chunk is immediately inserted (before the FMT chunk), after the 32-bit chunk size field at offset 4 is set to -1 (0xFFFFFFFF) in RF64 simplest form. By using a simple sequential table mechanism, the DS64 chunk will contain the data chunk(s), pointing to additional DATA chunks. The first 4 bytes of the file are then being changed from ‘RIFF’ to ‘BW64’.
Additional chunks defined by RF64 files include:
- BW64 : Replacing “RIFF”
- ds64 : 64-bit data size, first chunk under BW64
- axml : Replaced by BW64
- bxml : Similar to “axml” in BWF (ITU-R BS.1352-3), but it is compressed
- sxml : XML data related to sound
- chna : Info of the channel
- JUNK : ds64 placeholder
FAQ
Q1: Can I play an RA64 file directly in media player software?
A: No, standard media players cannot play RA64 files as they are data archives, not direct audio files.
Q2: What software do I need to open and use an RA64 file?
A: You need compatible sample management software, often from Roland (e.g., Roland Cloud Librarians, SP-404SX Librarian) or specific digital audio workstations (DAWs) with support for the format.
Q3: How do I convert an RA64 file to MP3 or WAV?
A: You don’t convert the archive itself. You must open it in its dedicated software, which will access the referenced samples, and then you can export those individual audio files to a standard format.
Q4: I have an RA64 file but no audio. What’s missing?
A: You are likely missing the accompanying folder of actual sample files (like .WAV files) that the RA64 archive is designed to organize and reference.
Q5: Is the RA64 format still used today?
A: Yes, it remains in use within niche music production circles, particularly by users of specific legacy or modern Roland hardware that relies on this archival system for sample management.
