I am trying to get the raw audio data from the system microphone using AudioToolbox and CoreFoundation frameworks. So far the writing packets to file logic works but when I try to capture the raw data into a file I am getting white noise. Callback function looks like this: static void MyAQInputCallback(void *inUserData, AudioQueueRef inQueue, AudioQueueBufferRef inBuffer, const AudioTimeStamp *inStartTime, UInt32 inNumPackets, const AudioStreamPacketDescription *inPacketDesc) { MyRecorder *recorder = (MyRecorder *)inUserData; if (inNumPackets > 0) { CheckError(AudioFileWritePackets(recorder->recordFile, FALSE, inBuffer->mAudioDataByteSize, inPacketDesc, recorder->recordPacket, &inNumPackets, inBuffer->mAudioData), "AudioFileWritePackets failed"); recorder->recordPacket += inNumPackets; int sampleCount = inBuffer->mAudioDataByteSize / sizeof(AUDIO_DATA_TYPE_FORMAT); AUDIO_DATA_TYPE_FORMAT* samples = (AUDIO_DATA_TYPE_FORMAT*)inBuffer->mAudioData; FILE *fp = fopen(filename, "a"); for (int i = 0; i < sampleCount; i++){ fprintf(fp, "%i;\n",samples[i]); } fclose(fp); } if (recorder->running) CheckError(AudioQueueEnqueueBuffer(inQueue, inBuffer, 0, NULL), "AudioQueueEnqueueBuffer failed"); } Some parameters: NumberRecordBuffers = 3 buffer duration = 0.1 format->mFramesPerPacket = 4096 samplerate = 44100 inNumPackets = 1 recordFormat.mFormatID = kAudioFormatAppleLossless; recordFormat.mChannelsPerFrame = 1; recordFormat.mBitsPerChannel = 16; Is this the correct way to do this? I could not find much information in the documentation. Any help is appreciated. Thank you in advance.