Audio Recording in .wav format in Android Programming



Step 1 : Select File -> New -> Project -> Android Application Project (or) Android Project. Fill the forms and click "Finish" button. If you have any doubt regarding create a new project Click Here.
 
 
Step 2 : Open res -> layout -> activity_main.xml (or) main.xml and add following code :
 
 
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="20dip">
   
    <ImageView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher"
        android:scaleType="fitCenter"/>
   
        <TextView 
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/app_info"
        android:layout_weight="1.0"
        android:textSize="20dip"/>
       
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">
       
        <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/btnStart"
                android:text="@string/start_recording"
                android:layout_weight="1.0"/>
               
                <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/btnStop"
                android:text="@string/stop_recording"
                android:layout_weight="1.0"/>
    </LinearLayout>
</LinearLayout>
 
 
Step 3 : Open src -> package -> MainActivity.java and add following code :
 
 
package com.Hemanth.rec;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.app.Activity;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.Button;

public class MainActivity extends Activity {
        private static final int RECORDER_BPP = 16;
        private static final String AUDIO_RECORDER_FILE_EXT_WAV = ".wav";
        private static final String AUDIO_RECORDER_FOLDER = "AudioRecorder";
        private static final String AUDIO_RECORDER_TEMP_FILE = "record_temp.raw";
        private static final int RECORDER_SAMPLERATE = 44100;
        private static final int RECORDER_CHANNELS = AudioFormat.CHANNEL_IN_STEREO;
        private static final int RECORDER_AUDIO_ENCODING = AudioFormat.ENCODING_PCM_16BIT;
       
        private AudioRecord recorder = null;
        private int bufferSize = 0;
        private Thread recordingThread = null;
        private boolean isRecording = false;
       
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       
        setButtonHandlers();
        enableButtons(false);
       
        bufferSize = AudioRecord.getMinBufferSize(8000,
                AudioFormat.CHANNEL_CONFIGURATION_MONO,
                AudioFormat.ENCODING_PCM_16BIT);
    }

        private void setButtonHandlers() {
                ((Button)findViewById(R.id.btnStart)).setOnClickListener(btnClick);
        ((Button)findViewById(R.id.btnStop)).setOnClickListener(btnClick);
        }
       
        private void enableButton(int id,boolean isEnable){
                ((Button)findViewById(id)).setEnabled(isEnable);
        }
       
        private void enableButtons(boolean isRecording) {
                enableButton(R.id.btnStart,!isRecording);
                enableButton(R.id.btnStop,isRecording);
        }
       
        private String getFilename(){
                String filepath = Environment.getExternalStorageDirectory().getPath();
                File file = new File(filepath,AUDIO_RECORDER_FOLDER);
               
                if(!file.exists()){
                        file.mkdirs();
                }
               
                return (file.getAbsolutePath() + "/" + System.currentTimeMillis() + AUDIO_RECORDER_FILE_EXT_WAV);
        }
       
        private String getTempFilename(){
                String filepath = Environment.getExternalStorageDirectory().getPath();
                File file = new File(filepath,AUDIO_RECORDER_FOLDER);
               
                if(!file.exists()){
                        file.mkdirs();
                }
               
                File tempFile = new File(filepath,AUDIO_RECORDER_TEMP_FILE);
               
                if(tempFile.exists())
                        tempFile.delete();
               
                return (file.getAbsolutePath() + "/" + AUDIO_RECORDER_TEMP_FILE);
        }
       
        private void startRecording(){
                recorder = new AudioRecord(MediaRecorder.AudioSource.MIC,
                                                RECORDER_SAMPLERATE, RECORDER_CHANNELS,RECORDER_AUDIO_ENCODING, bufferSize);
               
                int i = recorder.getState();
                if(i==1)
                    recorder.startRecording();
               
                isRecording = true;
               
                recordingThread = new Thread(new Runnable() {
                       
                        @Override
                        public void run() {
                                writeAudioDataToFile();
                        }
                },"AudioRecorder Thread");
               
                recordingThread.start();
        }
       
        private void writeAudioDataToFile(){
                byte data[] = new byte[bufferSize];
                String filename = getTempFilename();
                FileOutputStream os = null;
               
                try {
                        os = new FileOutputStream(filename);
                } catch (FileNotFoundException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                }
               
                int read = 0;
               
                if(null != os){
                        while(isRecording){
                                read = recorder.read(data, 0, bufferSize);
                               
                                if(AudioRecord.ERROR_INVALID_OPERATION != read){
                                        try {
                                                os.write(data);
                                        } catch (IOException e) {
                                                e.printStackTrace();
                                        }
                                }
                        }
                       
                        try {
                                os.close();
                        } catch (IOException e) {
                                e.printStackTrace();
                        }
                }
        }
       
        private void stopRecording(){
                if(null != recorder){
                        isRecording = false;
                       
                        int i = recorder.getState();
                        if(i==1)
                            recorder.stop();
                        recorder.release();
                       
                        recorder = null;
                        recordingThread = null;
                }
               
                copyWaveFile(getTempFilename(),getFilename());
                deleteTempFile();
        }

        private void deleteTempFile() {
                File file = new File(getTempFilename());
               
                file.delete();
        }
       
        private void copyWaveFile(String inFilename,String outFilename){
                FileInputStream in = null;
                FileOutputStream out = null;
                long totalAudioLen = 0;
                long totalDataLen = totalAudioLen + 36;
                long longSampleRate = RECORDER_SAMPLERATE;
                int channels = 2;
                long byteRate = RECORDER_BPP * RECORDER_SAMPLERATE * channels/8;
               
                byte[] data = new byte[bufferSize];
               
                try {
                        in = new FileInputStream(inFilename);
                        out = new FileOutputStream(outFilename);
                        totalAudioLen = in.getChannel().size();
                        totalDataLen = totalAudioLen + 36;
                       
                        AppLog.logString("File size: " + totalDataLen);
                       
                        WriteWaveFileHeader(out, totalAudioLen, totalDataLen,
                                        longSampleRate, channels, byteRate);
                       
                        while(in.read(data) != -1){
                                out.write(data);
                        }
                       
                        in.close();
                        out.close();
                } catch (FileNotFoundException e) {
                        e.printStackTrace();
                } catch (IOException e) {
                        e.printStackTrace();
                }
        }

        private void WriteWaveFileHeader(
                        FileOutputStream out, long totalAudioLen,
                        long totalDataLen, long longSampleRate, int channels,
                        long byteRate) throws IOException {
               
                byte[] header = new byte[44];
               
                header[0] = 'R';  // RIFF/WAVE header
                header[1] = 'I';
                header[2] = 'F';
                header[3] = 'F';
                header[4] = (byte) (totalDataLen & 0xff);
                header[5] = (byte) ((totalDataLen >> 8) & 0xff);
                header[6] = (byte) ((totalDataLen >> 16) & 0xff);
                header[7] = (byte) ((totalDataLen >> 24) & 0xff);
                header[8] = 'W';
                header[9] = 'A';
                header[10] = 'V';
                header[11] = 'E';
                header[12] = 'f';  // 'fmt ' chunk
                header[13] = 'm';
                header[14] = 't';
                header[15] = ' ';
                header[16] = 16;  // 4 bytes: size of 'fmt ' chunk
                header[17] = 0;
                header[18] = 0;
                header[19] = 0;
                header[20] = 1;  // format = 1
                header[21] = 0;
                header[22] = (byte) channels;
                header[23] = 0;
                header[24] = (byte) (longSampleRate & 0xff);
                header[25] = (byte) ((longSampleRate >> 8) & 0xff);
                header[26] = (byte) ((longSampleRate >> 16) & 0xff);
                header[27] = (byte) ((longSampleRate >> 24) & 0xff);
                header[28] = (byte) (byteRate & 0xff);
                header[29] = (byte) ((byteRate >> 8) & 0xff);
                header[30] = (byte) ((byteRate >> 16) & 0xff);
                header[31] = (byte) ((byteRate >> 24) & 0xff);
                header[32] = (byte) (2 * 16 / 8);  // block align
                header[33] = 0;
                header[34] = RECORDER_BPP;  // bits per sample
                header[35] = 0;
                header[36] = 'd';
                header[37] = 'a';
                header[38] = 't';
                header[39] = 'a';
                header[40] = (byte) (totalAudioLen & 0xff);
                header[41] = (byte) ((totalAudioLen >> 8) & 0xff);
                header[42] = (byte) ((totalAudioLen >> 16) & 0xff);
                header[43] = (byte) ((totalAudioLen >> 24) & 0xff);

                out.write(header, 0, 44);
        }
       
        private View.OnClickListener btnClick = new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                        switch(v.getId()){
                                case R.id.btnStart:{
                                        AppLog.logString("Start Recording");
                                       
                                        enableButtons(true);
                                        startRecording();
                                                       
                                        break;
                                }
                                case R.id.btnStop:{
                                        AppLog.logString("Start Recording");
                                       
                                        enableButtons(false);
                                        stopRecording();
                                       
                                        break;
                                }
                        }
                }
        };
}
 
Step 4 : Open src -> package -> AppLog.java and add following code :
 
package com.Hemanth.rec;

import android.util.Log;

public class AppLog {
   
     private static final String APP_TAG = "AudioRecorder";
    
     public static int logString(String message){
             return Log.i(APP_TAG,message);
     }

}
 
 
 
Step 5 :  Strings.xml and add following code :
 
<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">Rec</string>
    <string name="action_settings">Settings</string>
    <string name="hello_world">Hello world!</string>
   
    <string name="app_info">This is a sample application to record audio.\n\nTo start recording press \&quot;Record\&quot; button, to stop recording press \&quot;Stop\&quot; button.</string>
    <string name="choose_format_title">Choose Audio Format</string>
    <string name="start_recording">Record</string>
    <string name="stop_recording">Stop</string>
    <string name="audio_format">Format</string>

</resources>
 
 
 
Step 6 : Open AndroidManifest.xml and add following code :
 
 
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.Hemanth.rec"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />
   
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
    <uses-permission android:name="android.permission.RECORD_AUDIO"></uses-permission>

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.Hemanth.rec.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>
 
Step 5 : Our output will be like this :