RF64 WAVE

Traditionally WAVE file format has a file size limit of 4GB.

In 2009, European Broadcasting Union published EBU Tech 3306 document to update WAVE format to enable file size > 4GB.

Adobe Audition, Audacity, Pro Tools, Nuendo, Cubase, Samplitude, Saracon, and Sox outputs this file when file size exceeds 4GB. File extension remains the same ".wav". I think mime type is also the same Audio/wav.

Microsoft Media Foundation API can read RF64 WAVE.

Changes from traditional RIFF WAVE to RF64 WAVE is as follows, very simple and minimum:

①riff.desc is now 'RF64'. RIFF chunk size == 0xffffffff
②New subchunk 'ds64' is inserted before 'fmt ' subchunk. In ds64 subchunk there is a riff chunk size of 8 bytes and data chunk size of 8 bytes.
③DATA subchunk size == 0xffffffff

Other subchunks are remains the same.

4GB limitation is serious problem for high resolution audio or multichannel audio. For example, 768kHz 32bit 2ch PCM (or 192kHz 32bit 8ch PCM) exceeds 4GB in 11 minutes.

Reference

EBU Tech 3306 "MBWF / RF64: An Extended File Format for Audio"
https://tech.ebu.ch/docs/tech/tech3306-2009.pdf