Android : Record sound in mp3 format

Question

I am building an android app, having feature of capturing sound through microphone and playing it through headphone. For this, I have used "AudioRecord" and "AudioTrack". Following is some part of code that I am using,(just for understanding)

mInBufferSize = AudioRecord.getMinBufferSize(mSampleRate,
            AudioFormat.CHANNEL_CONFIGURATION_MONO, mFormat);
mOutBufferSize = AudioTrack.getMinBufferSize(mSampleRate,
            AudioFormat.CHANNEL_CONFIGURATION_MONO, mFormat);
mAudioInput = new AudioRecord(MediaRecorder.AudioSource.MIC,
            mSampleRate, AudioFormat.CHANNEL_CONFIGURATION_MONO, mFormat,
            mInBufferSize);
mAudioOutput = new AudioTrack(AudioManager.STREAM_MUSIC, mSampleRate,
            AudioFormat.CHANNEL_CONFIGURATION_MONO, mFormat,
            mOutBufferSize, AudioTrack.MODE_STREAM);

But the main problem is that I want to record incoming sound in mp3 format? Please help me in this, I will really appreciate...

Thanks in Advance

Answer 1

There's a work around for saving .mp3 files using MediaRecorder. Here's how:

recorder = new MediaRecorder();
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
recorder.setOutputFile(Environment.getExternalStorageDirectory()
        .getAbsolutePath() + "/myrecording.mp3");
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
recorder.prepare();
recorder.start();

The important part here is the setOuputFormat and the setAudioEncoder. Apparently MediaRecorder records playable mp3 if you're using MediaRecorder.OutputFormat.MPEG_4 and MediaRecorder.AudioEncoder.AAC together. Hope this helps somebody.

Of course, if you'd rather use the AudioRecorder class I think the source code Chirag linked below should work just fine - https://github.com/yhirano/Mp3VoiceRecorderSampleForAndroid (although you might need to translate some of it from Japanese to English)

Edit: As Bruno, and a few others pointed out in the comments, this does not encode the file in MP3. The encoding is still AAC. However, if you try to play a sound, saved using a .mp3 extension via the code above, it will still play without issues because most media players are smart enough to detect the real encoding.