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Android : Audio Capture

Tutorial by:      Date: 2018-01-24 23:51:56

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Android has built a microphone through which you can capture and store audio, or play it on your phone. There are several ways to do this but the most common method is through the MediaRecorder class

To access the MediaRecorder class for recording Android audio or video, you will first create an example of the MediaRecorder class, its syntax is given below.


MediaRecorder myAudioRecorder = new MediaRecorder();

Now you will set the source , output and encoding format and output file. Their syntax is given below.


myAudioRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
myAudioRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
myAudioRecorder.setAudioEncoder(MediaRecorder.OutputFormat.AMR_NB);
myAudioRecorder.setOutputFile(outputFile);

After specifying the audio source and format and its output file, we can then call the two basic methods prepare and start to start recording the audio.


myAudioRecorder.prepare();
myAudioRecorder.start();

Apart from these methods , there are other methods listed in the MediaRecorder class that allows you more control over audio and video recording.

Sr.No Method & description
1 setAudioSource()

This method specifies the source of audio to be recorded

2 setVideoSource()

This method specifies the source of video to be recorded

3 setOutputFormat()

This method specifies the audio format in which audio to be stored

4 setAudioEncoder()

This method specifies the audio encoder to be used

5 setOutputFile()

This method configures the path to the file into which the recorded audio is to be stored

6 stop()

This method stops the recording process.

7 release()

This method should be called when the recorder instance is needed.

Example

This example provides demonstration of MediaRecorder class to capture audio and then MediaPlayer class to play that recorded audio.

To experiment with this example , you need to run this on an actual device.

Steps Description
1 You can use the Android Studio IDE to create an Android application and it com. Explore.EremacheRishna Designate as an audiocopure under the microphones; When creating this project, to use a high level API, make sure you target the SDK and compile it on the latest version of Android SDK.
2 Modify src/MainActivity.java file to add AudioCapture code
3 Modify layout XML file res/layout/activity_main.xml add any GUI component if required.
4 Modify AndroidManifest.xml to add necessary permissions.
5 Run the application and choose a running android device and install the application on it and verify the results.

Here is the content of src/MainActivity.java


package com.example.sairamkrishna.myapplication;

import android.app.Activity;
import android.media.MediaPlayer;
import android.media.MediaRecorder;

import android.os.Bundle;
import android.os.Environment;

import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;

import android.widget.ImageView;
import android.widget.Toast;
import java.io.IOException;


public class MainActivity extends Activity {
   Button play,stop,record;
   private MediaRecorder myAudioRecorder;
   private String outputFile = null;
   
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      
      play=(Button)findViewById(R.id.button3);
      stop=(Button)findViewById(R.id.button2);
      record=(Button)findViewById(R.id.button);
      
      stop.setEnabled(false);
      play.setEnabled(false);
      outputFile = Environment.getExternalStorageDirectory().getAbsolutePath() + "/recording.3gp";;
      
      myAudioRecorder=new MediaRecorder();
      myAudioRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
      myAudioRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
      myAudioRecorder.setAudioEncoder(MediaRecorder.OutputFormat.AMR_NB);
      myAudioRecorder.setOutputFile(outputFile);
      
      record.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            try {
               myAudioRecorder.prepare();
               myAudioRecorder.start();
            }
            
            catch (IllegalStateException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
            }
            
            catch (IOException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
            }
            
            record.setEnabled(false);
            stop.setEnabled(true);
            
            Toast.makeText(getApplicationContext(), "Recording started", Toast.LENGTH_LONG).show();
         }
      });
      
      stop.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            myAudioRecorder.stop();
            myAudioRecorder.release();
            myAudioRecorder  = null;
            
            stop.setEnabled(false);
            play.setEnabled(true);
            
            Toast.makeText(getApplicationContext(), "Audio recorded successfully",Toast.LENGTH_LONG).show();
         }
      });
      
      play.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) throws IllegalArgumentException,SecurityException,IllegalStateException {
            MediaPlayer m = new MediaPlayer();
            
            try {
               m.setDataSource(outputFile);
            }
            
            catch (IOException e) {
               e.printStackTrace();
            }
            
            try {
               m.prepare();
            }
            
            catch (IOException e) {
               e.printStackTrace();
            }
            
            m.start();
            Toast.makeText(getApplicationContext(), "Playing audio", Toast.LENGTH_LONG).show();
         }
      });
   }
   
   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is present.
      getMenuInflater().inflate(R.menu.menu_main, menu);
      return true;
   }
   
   @Override
   public boolean onOptionsItemSelected(MenuItem item) {
      // Handle action bar item clicks here. The action bar will
      // automatically handle clicks on the Home/Up button, so long
      // as you specify a parent activity in AndroidManifest.xml.
      
      int id = item.getItemId();
      
      //noinspection SimplifiableIfStatement
      if (id == R.id.action_settings) {
         return true;
      }
      return super.onOptionsItemSelected(item);
   }
}

Here is the content of activity_main.xml


 xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools" 
   android:layout_width="match_parent"
   android:layout_height="match_parent" 
   android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   android:paddingBottom="@dimen/activity_vertical_margin" 
   tools:context=".MainActivity">
   
   
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Android Audio Recording"
      android:id="@+id/textView"
      android:textSize="30dp"
      android:layout_alignParentTop="true"
      android:layout_alignParentRight="true"
      android:layout_alignParentEnd="true" />
      
   
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Fastread"
      android:id="@+id/textView2"
      android:textColor="#ff3eff0f"
      android:textSize="35dp"
      android:layout_below="@+id/textView"
      android:layout_centerHorizontal="true" />
      
   
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/imageView"
      android:src="@drawable/logo"
      android:layout_below="@+id/textView2"
      android:layout_alignLeft="@+id/textView2"
      android:layout_alignStart="@+id/textView2"
      android:layout_alignRight="@+id/textView2"
      android:layout_alignEnd="@+id/textView2" />
      
   
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Record"
      android:id="@+id/button"
      android:layout_below="@+id/imageView"
      android:layout_alignParentLeft="true"
      android:layout_alignParentStart="true"
      android:layout_marginTop="59dp" />
      
   
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Stop"
      android:id="@+id/button2"
      android:layout_alignTop="@+id/button"
      android:layout_centerHorizontal="true" />
      
   
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="play"
      android:id="@+id/button3"
      android:layout_alignTop="@+id/button2"
      android:layout_alignRight="@+id/textView"
      android:layout_alignEnd="@+id/textView" />

Here is the content of Strings.xml


    name="app_name">My Application
    name="hello_world">Hello world!
    name="action_settings">Settings

Here is the content of AndroidManifest.xml


xml version="1.0" encoding="utf-8"?>
 xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.example.audiocapture"
   android:versionCode="1"
   android:versionName="1.0" >
   
    android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    android:name="android.permission.RECORD_AUDIO" /> 

   
      android:allowBackup="true"
      android:icon="@drawable/ic_launcher"
      android:label="@string/app_name"
      android:theme="@style/AppTheme" >
      
      
         android:name="com.example.audiocapture.MainActivity"
         android:label="@string/app_name" >
      
         
             android:name="android.intent.action.MAIN" />
             android:name="android.intent.category.LAUNCHER" />

   

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from Android studio, open one of your project's activity files and click Run icon from the toolbar. Before starting your application, Android studio will display a screen.

Now by default you will see stop and play button disable. Just press the Record button and your application will start recording the audio. It will display a screen.

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