WRID>RIFF-WAVE>fact

TODO: overview

The "fact" chunk is required if the waveform data is contained in a "wavl" LIST chunk and for all compressed audio formats. The chunk is not required for PCM files using the "data" chunk format.

[RIFF1991]

...

Chunk Name Bytes Type conditionDescriptionWRID
fact id 4 u8[4] id = fact ...>id
fact size 4 u32 ...>size
fact samples 4 u32 Number of samples. RIFF1991 named this field dwFileSize, even though it's documented as "Number of samples" ...>samples

...

The "fact" chunk will be expanded to include any other information required by future WAVE formats. Added fields will appear following the field. Applications can use the chunk size field to determine which fields are present.

[RIFF1991]

The above seems... not great. :/ It looks as though the various compressed file formats optionally add additional data here. TODO: find and add refrence supporting this comment.

TODO: check and see if [RIFF1994] adds more.

Learning References

Specification

  • [RIFF1991] Multimedia Programming Interface and Data Specifications (1991). See pages 56-65.
  • [RIFF1994] New Multimedia Data Types and Data Techniques (1994). See pages 12-22.