kAudioFilePropertyMagicCookieData

A pointer to memory set up by the caller. Some file types require that a magic cookie be provided before packets can be written to an audio file. Set this property before you call Audiofilewritebytes(_:_:_:_:_:) or Audiofilewritepackets(_:_:_:_:_:_:_:) if a magic cookie exists.

var kAudioFilePropertyMagicCookieData: AudioFilePropertyID { get }