CODEWITHSUNDEEP
androidaudiotrackandroid-audiorecord
Jeff Bic
Jeff Bic

Reputation: 566

android sdk realtime audio record

I use this code to record and play back recorded audio in real time using the AudioTrack and AudioRecord

package com.example.audiotrack;

import android.app.Activity;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioRecord;
import android.media.AudioTrack;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends Activity {
    private int freq = 8000;
    private AudioRecord audioRecord = null;
    private Thread Rthread = null;

    private AudioManager audioManager = null;
    private AudioTrack audioTrack = null;
    byte[] buffer = new byte[freq];
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);
        final int bufferSize = AudioRecord.getMinBufferSize(freq,
                AudioFormat.CHANNEL_CONFIGURATION_MONO,
                AudioFormat.ENCODING_PCM_16BIT);


        audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, freq,
                AudioFormat.CHANNEL_CONFIGURATION_MONO,
                MediaRecorder.AudioEncoder.AMR_NB, bufferSize);

        audioTrack = new AudioTrack(AudioManager.ROUTE_HEADSET, freq,
                AudioFormat.CHANNEL_CONFIGURATION_MONO,
                MediaRecorder.AudioEncoder.AMR_NB, bufferSize,
                AudioTrack.MODE_STREAM);



        audioTrack.setPlaybackRate(freq);
         final byte[] buffer = new byte[bufferSize];
        audioRecord.startRecording();
        Log.i("info", "Audio Recording started");
        audioTrack.play();
        Log.i("info", "Audio Playing started");
        Rthread = new Thread(new Runnable() {
            public void run() {
                while (true) {
                    try {
                        audioRecord.read(buffer, 0, bufferSize);                                    
                        audioTrack.write(buffer, 0, buffer.length);

                    } catch (Throwable t) {
                        Log.e("Error", "Read write failed");
                        t.printStackTrace();
                    }
                }
            }
        });
        Rthread.start();
    }

}

My problem :

1.the quality of audio is bad

2.when I try different frequencies the app crashes

Upvotes: 3

Views: 6666

Answers (1)

MP23
MP23

Reputation: 1773

Audio quality can be bad because you are using AMR codec to compress audio data. AMR uses compression based on acoustic model so any other sounds than human speech will be in poor quality

Instead of

MediaRecorder.AudioEncoder.AMR_NB

try 

AudioFormat.ENCODING_PCM_16BIT

AudioRecord is low level tool, so you must take care of, parameters compatibility on your own. As said in documentation many frequencies are not guranteed to work.

So it is good idea to go through all combinations and check wich of them are accesible before trying to record or play.

Nice solution was mentioned few times on stackOverflow, e.g here Frequency detection on Android - AudioRecord

check public AudioRecord findAudioRecord() method

Upvotes: 2

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