AudioFileReadPacketData

function AudioFileReadPacketData(

  inAudioFile: AudioFileID;

  inUseCache: Boolean;

  var ioNumBytes: UInt32;

  outPacketDescriptions: AudioStreamPacketDescriptionPtr;

  inStartingPacket: SInt64;

  var ioNumPackets: UInt32;

  outBuffer: UnivPtr

):OSStatus;