Recording .Wav with Android AudioRecorder

Question

I have read a lot of pages about Android's AudioRecorder. You can see a list of them below the question.

I'm trying to record audio with AudioRecorder, but it's not working well.

public class MainActivity extends Activity {

AudioRecord ar = null;
int buffsize = 0;

int blockSize = 256;
boolean isRecording = false;
private Thread recordingThread = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


}

public void baslat(View v)
{
            // when click to START 
    buffsize = AudioRecord.getMinBufferSize(44100, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);
    ar = new AudioRecord(MediaRecorder.AudioSource.MIC, 44100, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT, buffsize);

    ar.startRecording();

    isRecording = true;
    recordingThread = new Thread(new Runnable() {
        public void run() {
            writeAudioDataToFile();
        }
    }, "AudioRecorder Thread");
    recordingThread.start();
}
public void durdur(View v)
{
            // When click to STOP
    ar.stop();
    isRecording = false;
}

private void writeAudioDataToFile() {
    // Write the output audio in byte

    String filePath = "/sdcard/voice8K16bitmono.wav";
    short sData[] = new short[buffsize/2];

    FileOutputStream os = null;
    try {
        os = new FileOutputStream(filePath);
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }

    while (isRecording) {
        // gets the voice output from microphone to byte format

        ar.read(sData, 0, buffsize/2);
        Log.d("eray","Short wirting to file" + sData.toString());
        try {
            // // writes the data to file from buffer
            // // stores the voice buffer
            byte bData[] = short2byte(sData);
            os.write(bData, 0, buffsize);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    try {
        os.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

private byte[] short2byte(short[] sData) {
    int shortArrsize = sData.length;
    byte[] bytes = new byte[shortArrsize * 2];
    for (int i = 0; i < shortArrsize; i++) {
        bytes[i * 2] = (byte) (sData[i] & 0x00FF);
        bytes[(i * 2) + 1] = (byte) (sData[i] >> 8);
        sData[i] = 0;
    }
    return bytes;

}

It's creating a .wav file but, when I try to listen to it, it's not opening. I'm getting a "file not supported" error. I've tried to play the file with quite a few media player applications.

NOTE : I have to use AudioRecorder instead of MediaRecorder because my app will be doing another process while recording (displaying an equalizer) .

Here is the list of pages that I've read about this subject:

1. http://developer.android.com/reference/android/media/AudioRecord.html#read(short[],%20int,%20int)
2. Android AudioRecord example
3. http://audiorecordandroid.blogspot.in
4. AudioRecord object not initializing
5. Recording a wav file from the mic in Android - problems
6. http://i-liger.com/article/android-wav-audio-recording
7. Creating a WAV file from raw PCM data using the Android SDK
8. Capturing Sound for Analysis and Visualizing Frequencies in Android

There are a lot of different ways to go about this. I've tried lots of them but nothing works for me. I've been working on this problem for about 6 hours now so I would appreciate a definitive answer, ideally some sample code.

Answer 1

PCMAudioHelper solved my problem. I'll modify this answer and explain it but firstly i have to do some tests over this class.

Answer 2

I wrote a simple (by which you should read, not to professional standards) class to do this yesterday, and it works.

private class Wave {
    private final int LONGINT = 4;
    private final int SMALLINT = 2;
    private final int INTEGER = 4;
    private final int ID_STRING_SIZE = 4;
    private final int WAV_RIFF_SIZE = LONGINT + ID_STRING_SIZE;
    private final int WAV_FMT_SIZE = (4 * SMALLINT) + (INTEGER * 2) + LONGINT + ID_STRING_SIZE;
    private final int WAV_DATA_SIZE = ID_STRING_SIZE + LONGINT;
    private final int WAV_HDR_SIZE = WAV_RIFF_SIZE + ID_STRING_SIZE + WAV_FMT_SIZE + WAV_DATA_SIZE;
    private final short PCM = 1;
    private final int SAMPLE_SIZE = 2;
    int cursor, nSamples;
    byte[] output;

    public Wave(int sampleRate, short nChannels, short[] data, int start, int end) {
        nSamples = end - start + 1;
        cursor = 0;
        output = new byte[nSamples * SMALLINT + WAV_HDR_SIZE];
        buildHeader(sampleRate, nChannels);
        writeData(data, start, end);
    }

    // ------------------------------------------------------------
    private void buildHeader(int sampleRate, short nChannels) {
        write("RIFF");
        write(output.length);
        write("WAVE");
        writeFormat(sampleRate, nChannels);
    }

    // ------------------------------------------------------------
    public void writeFormat(int sampleRate, short nChannels) {
        write("fmt ");
        write(WAV_FMT_SIZE - WAV_DATA_SIZE);
        write(PCM);
        write(nChannels);
        write(sampleRate);
        write(nChannels * sampleRate * SAMPLE_SIZE);
        write((short) (nChannels * SAMPLE_SIZE));
        write((short) 16);
    }

    // ------------------------------------------------------------
    public void writeData(short[] data, int start, int end) {
        write("data");
        write(nSamples * SMALLINT);
        for (int i = start; i <= end; write(data[i++])) ;
    }

    // ------------------------------------------------------------
    private void write(byte b) {
        output[cursor++] = b;
    }

    // ------------------------------------------------------------
    private void write(String id) {
        if (id.length() != ID_STRING_SIZE)
            Utils.logError("String " + id + " must have four characters.");
        else {
            for (int i = 0; i < ID_STRING_SIZE; ++i) write((byte) id.charAt(i));
        }
    }

    // ------------------------------------------------------------
    private void write(int i) {
        write((byte) (i & 0xFF));
        i >>= 8;
        write((byte) (i & 0xFF));
        i >>= 8;
        write((byte) (i & 0xFF));
        i >>= 8;
        write((byte) (i & 0xFF));
    }

    // ------------------------------------------------------------
    private void write(short i) {
        write((byte) (i & 0xFF));
        i >>= 8;
        write((byte) (i & 0xFF));
    }

    // ------------------------------------------------------------
    public boolean wroteToFile(String filename) {
        boolean ok = false;

        try {
            File path = new File(getFilesDir(), filename);
            FileOutputStream outFile = new FileOutputStream(path);
            outFile.write(output);
            outFile.close();
            ok = true;
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            ok = false;
        } catch (IOException e) {
            ok = false;
            e.printStackTrace();
        }
        return ok;
    }
}

Hope this helps

Answer 3

You might find this OMRECORDER helpful for recording .WAV format.

In case if .aac works with you then check out this WhatsappAudioRecorder:

On startRecording button click :

1. Initialise new thread.
2. Create file with .aac extension.
3. Create output stream of file.
4. Set output
5. SetListener and execute thread.

OnStopClick :

1. Interrupt the thread and audio will be saved in file.

Here is full gist of for reference :

import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaCodec;
import android.media.MediaCodecInfo;
import android.media.MediaFormat;
import android.media.MediaRecorder;
import android.os.Build;
import android.util.Log;

import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;

public class AudioRecordThread implements Runnable {

    private static final String TAG = AudioRecordThread.class.getSimpleName();

    private static final int SAMPLE_RATE = 44100;
    private static final int SAMPLE_RATE_INDEX = 4;
    private static final int CHANNELS = 1;
    private static final int BIT_RATE = 32000;

    private final int bufferSize;
    private final MediaCodec mediaCodec;
    private final AudioRecord audioRecord;
    private final OutputStream outputStream;

    private OnRecorderFailedListener onRecorderFailedListener;


    AudioRecordThread(OutputStream outputStream, OnRecorderFailedListener onRecorderFailedListener) throws IOException {

        this.bufferSize = AudioRecord.getMinBufferSize(SAMPLE_RATE, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);
        this.audioRecord = createAudioRecord(this.bufferSize);
        this.mediaCodec = createMediaCodec(this.bufferSize);
        this.outputStream = outputStream;
        this.onRecorderFailedListener = onRecorderFailedListener;

        this.mediaCodec.start();

        try {
            audioRecord.startRecording();
        } catch (Exception e) {
            Log.w(TAG, e);
            mediaCodec.release();
            throw new IOException(e);
        }
    }

    @Override
    public void run() {
        if (onRecorderFailedListener != null) {
            Log.d(TAG, "onRecorderStarted");
            onRecorderFailedListener.onRecorderStarted();
        }
        MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
        ByteBuffer[] codecInputBuffers = mediaCodec.getInputBuffers();
        ByteBuffer[] codecOutputBuffers = mediaCodec.getOutputBuffers();

        try {
            while (!Thread.interrupted()) {

                boolean success = handleCodecInput(audioRecord, mediaCodec, codecInputBuffers, Thread.currentThread().isAlive());
                if (success)
                    handleCodecOutput(mediaCodec, codecOutputBuffers, bufferInfo, outputStream);
            }
        } catch (IOException e) {
            Log.w(TAG, e);
        } finally {
            mediaCodec.stop();
            audioRecord.stop();

            mediaCodec.release();
            audioRecord.release();

            try {
                outputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }


    private boolean handleCodecInput(AudioRecord audioRecord,
                                     MediaCodec mediaCodec, ByteBuffer[] codecInputBuffers,
                                     boolean running) throws IOException {
        byte[] audioRecordData = new byte[bufferSize];
        int length = audioRecord.read(audioRecordData, 0, audioRecordData.length);

        if (length == AudioRecord.ERROR_BAD_VALUE ||
                length == AudioRecord.ERROR_INVALID_OPERATION ||
                length != bufferSize) {

            if (length != bufferSize) {
                if (onRecorderFailedListener != null) {
                    Log.d(TAG, "length != BufferSize calling onRecordFailed");
                    onRecorderFailedListener.onRecorderFailed();
                }
                return false;
            }
        }

        int codecInputBufferIndex = mediaCodec.dequeueInputBuffer(10 * 1000);

        if (codecInputBufferIndex >= 0) {
            ByteBuffer codecBuffer = codecInputBuffers[codecInputBufferIndex];
            codecBuffer.clear();
            codecBuffer.put(audioRecordData);
            mediaCodec.queueInputBuffer(codecInputBufferIndex, 0, length, 0, running ? 0 : MediaCodec.BUFFER_FLAG_END_OF_STREAM);
        }

        return true;
    }

    private void handleCodecOutput(MediaCodec mediaCodec,
                                   ByteBuffer[] codecOutputBuffers,
                                   MediaCodec.BufferInfo bufferInfo,
                                   OutputStream outputStream)
            throws IOException {
        int codecOutputBufferIndex = mediaCodec.dequeueOutputBuffer(bufferInfo, 0);

        while (codecOutputBufferIndex != MediaCodec.INFO_TRY_AGAIN_LATER) {
            if (codecOutputBufferIndex >= 0) {
                ByteBuffer encoderOutputBuffer = codecOutputBuffers[codecOutputBufferIndex];

                encoderOutputBuffer.position(bufferInfo.offset);
                encoderOutputBuffer.limit(bufferInfo.offset + bufferInfo.size);

                if ((bufferInfo.flags & MediaCodec.BUFFER_FLAG_CODEC_CONFIG) != MediaCodec.BUFFER_FLAG_CODEC_CONFIG) {
                    byte[] header = createAdtsHeader(bufferInfo.size - bufferInfo.offset);


                    outputStream.write(header);

                    byte[] data = new byte[encoderOutputBuffer.remaining()];
                    encoderOutputBuffer.get(data);
                    outputStream.write(data);
                }

                encoderOutputBuffer.clear();

                mediaCodec.releaseOutputBuffer(codecOutputBufferIndex, false);
            } else if (codecOutputBufferIndex == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
                codecOutputBuffers = mediaCodec.getOutputBuffers();
            }

            codecOutputBufferIndex = mediaCodec.dequeueOutputBuffer(bufferInfo, 0);
        }
    }


    private byte[] createAdtsHeader(int length) {
        int frameLength = length + 7;
        byte[] adtsHeader = new byte[7];

        adtsHeader[0] = (byte) 0xFF; // Sync Word
        adtsHeader[1] = (byte) 0xF1; // MPEG-4, Layer (0), No CRC
        adtsHeader[2] = (byte) ((MediaCodecInfo.CodecProfileLevel.AACObjectLC - 1) << 6);
        adtsHeader[2] |= (((byte) SAMPLE_RATE_INDEX) << 2);
        adtsHeader[2] |= (((byte) CHANNELS) >> 2);
        adtsHeader[3] = (byte) (((CHANNELS & 3) << 6) | ((frameLength >> 11) & 0x03));
        adtsHeader[4] = (byte) ((frameLength >> 3) & 0xFF);
        adtsHeader[5] = (byte) (((frameLength & 0x07) << 5) | 0x1f);
        adtsHeader[6] = (byte) 0xFC;

        return adtsHeader;
    }

    private AudioRecord createAudioRecord(int bufferSize) {
        AudioRecord audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, SAMPLE_RATE,
                AudioFormat.CHANNEL_IN_MONO,
                AudioFormat.ENCODING_PCM_16BIT, bufferSize * 10);

        if (audioRecord.getState() != AudioRecord.STATE_INITIALIZED) {
            Log.d(TAG, "Unable to initialize AudioRecord");
            throw new RuntimeException("Unable to initialize AudioRecord");
        }

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
            if (android.media.audiofx.NoiseSuppressor.isAvailable()) {
                android.media.audiofx.NoiseSuppressor noiseSuppressor = android.media.audiofx.NoiseSuppressor
                        .create(audioRecord.getAudioSessionId());
                if (noiseSuppressor != null) {
                    noiseSuppressor.setEnabled(true);
                }
            }
        }


        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
            if (android.media.audiofx.AutomaticGainControl.isAvailable()) {
                android.media.audiofx.AutomaticGainControl automaticGainControl = android.media.audiofx.AutomaticGainControl
                        .create(audioRecord.getAudioSessionId());
                if (automaticGainControl != null) {
                    automaticGainControl.setEnabled(true);
                }
            }
        }


        return audioRecord;
    }

    private MediaCodec createMediaCodec(int bufferSize) throws IOException {
        MediaCodec mediaCodec = MediaCodec.createEncoderByType("audio/mp4a-latm");
        MediaFormat mediaFormat = new MediaFormat();

        mediaFormat.setString(MediaFormat.KEY_MIME, "audio/mp4a-latm");
        mediaFormat.setInteger(MediaFormat.KEY_SAMPLE_RATE, SAMPLE_RATE);
        mediaFormat.setInteger(MediaFormat.KEY_CHANNEL_COUNT, CHANNELS);
        mediaFormat.setInteger(MediaFormat.KEY_MAX_INPUT_SIZE, bufferSize);
        mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, BIT_RATE);
        mediaFormat.setInteger(MediaFormat.KEY_AAC_PROFILE, MediaCodecInfo.CodecProfileLevel.AACObjectLC);

        try {
            mediaCodec.configure(mediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
        } catch (Exception e) {
            Log.w(TAG, e);
            mediaCodec.release();
            throw new IOException(e);
        }

        return mediaCodec;
    }

    interface OnRecorderFailedListener {
        void onRecorderFailed();

        void onRecorderStarted();
    }
}

Answer 4

I would add this as a comment but I don't yet have enough Stackoverflow rep points...

Opiatefuchs's link takes you to sample code that shows you the exact header formatting necessary to create a .wav file. I've been all over that code myself. Very helpful.

Answer 5

First you need know that wav file has its format -- header. so you can't just write the pure data to the .wav file.

Second the wav file header include the length of file . so you need write the header after recording.

My solution is , user AudioRecorder record the pcm file .

    byte[] audiodata = new byte[bufferSizeInBytes];

    FileOutputStream fos = null;
    int readsize = 0;
    try {
        fos = new FileOutputStream(pcmFileName, true);
    } catch (FileNotFoundException e) {
        Log.e("AudioRecorder", e.getMessage());
    }

    status = Status.STATUS_START;
    while (status == Status.STATUS_START && audioRecord != null) {
        readsize = audioRecord.read(audiodata, 0, bufferSizeInBytes);
        if (AudioRecord.ERROR_INVALID_OPERATION != readsize && fos != null) {

            if (readsize > 0 && readsize <= audiodata.length)
                    fos.write(audiodata, 0, readsize);
            } catch (IOException e) {
                Log.e("AudioRecorder", e.getMessage());
            }
        }
    }
    try {
        if (fos != null) {
            fos.close();
        }
    } catch (IOException e) {
        Log.e("AudioRecorder", e.getMessage());
    }

then convert it to wav file.

    byte buffer[] = null;
    int TOTAL_SIZE = 0;
    File file = new File(pcmPath);
    if (!file.exists()) {
        return false;
    }
    TOTAL_SIZE = (int) file.length();

    WaveHeader header = new WaveHeader();

    header.fileLength = TOTAL_SIZE + (44 - 8);
    header.FmtHdrLeth = 16;
    header.BitsPerSample = 16;
    header.Channels = 1;
    header.FormatTag = 0x0001;
    header.SamplesPerSec = 8000;
    header.BlockAlign = (short) (header.Channels * header.BitsPerSample / 8);
    header.AvgBytesPerSec = header.BlockAlign * header.SamplesPerSec;
    header.DataHdrLeth = TOTAL_SIZE;

    byte[] h = null;
    try {
        h = header.getHeader();
    } catch (IOException e1) {
        Log.e("PcmToWav", e1.getMessage());
        return false;
    }

    if (h.length != 44) 
        return false;


    File destfile = new File(destinationPath);
    if (destfile.exists())
        destfile.delete();


    try {
        buffer = new byte[1024 * 4]; // Length of All Files, Total Size
        InputStream inStream = null;
        OutputStream ouStream = null;

        ouStream = new BufferedOutputStream(new FileOutputStream(
                destinationPath));
        ouStream.write(h, 0, h.length);
        inStream = new BufferedInputStream(new FileInputStream(file));
        int size = inStream.read(buffer);
        while (size != -1) {
            ouStream.write(buffer);
            size = inStream.read(buffer);
        }
        inStream.close();
        ouStream.close();
    } catch (FileNotFoundException e) {
        Log.e("PcmToWav", e.getMessage());
        return false;
    } catch (IOException ioe) {
        Log.e("PcmToWav", ioe.getMessage());
        return false;
    }
    if (deletePcmFile) {
        file.delete();
    }
    Log.i("PcmToWav", "makePCMFileToWAVFile  success!" + new SimpleDateFormat("yyyy-MM-dd hh:mm").format(new Date()));
    return true;