audioFormat.mSampleRate = (Float64)samplerate;
audioFormat.mChannelsPerFrame = 2;
audioFormat.mFormatID = kAudioFormatLinearPCM;
audioFormat.mSampleRate = (Float64)samplerate;
audioFormat.mChannelsPerFrame = 2;
audioFormat.mFormatID = kAudioFormatLinearPCM;