WAV file

A WAV file is the everyday audio container: a header describing the format, a block of sample data, and room for extra metadata chunks.

A canonical file opens with a 44-byte header carrying a fmt chunk — PCM or IEEE float, channel count, sample rate — followed by the data chunk, and well-behaved readers skip chunks they don't recognize, which is exactly where wavetable metadata hides. Packed wavetable WAVs are structurally ordinary WAVs; what makes them wavetables is the frames-plus-metadata interpretation an importer layers on top.