Types.Waveval t : t Ctypes.structure F.typval frame_count : (Unsigned.uint, t Ctypes.structure) F.fieldval sample_rate : (Unsigned.uint, t Ctypes.structure) F.fieldval sample_size : (Unsigned.uint, t Ctypes.structure) F.fieldval channels : (Unsigned.uint, t Ctypes.structure) F.fieldval data : (unit Ctypes_static.ptr, t Ctypes.structure) F.field