Develop Reference

How can I create a microphone app on Android?

I want to create a microphone app on Android that will receive sound through the microphone and play through the speakerphone but I don't know exactly what classes and services I should use.

The core of your answer is to:
A) record and store, as stated here.
MediaRecorder recorder = new MediaRecorder();
String status = Environment.getExternalStorageState();
if(status.equals("mounted")){
String path = Environment.getExternalStorageDirectory().toString()+"/YOURFOLDER"; // your custom path
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP); // notice that this is the audio format, and you might want to change it to [other available audio formats][2]
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
recorder.setOutputFile(path);
recorder.prepare();
// To start recording
recorder.start();
// To stop recording
recorder.stop();
recorder.release();
} else {
// Handle the situation
}
[Other available audio formats | 2]
B) Get recordings, as stated partially here. You should then show them.
try {
String path = Environment.getExternalStorageDirectory().toString()+"/YOURFOLDER"; // your custom path
File directory = new File(path);
File[] files = directory.listFiles();
} catch {
// Handle errors (or maybe no files in the directory)
}
C) Play recordings, as stated partially here.
MediaPlayer mp = new MediaPlayer();
mp.setDataSource(Environment.getExternalStorageDirectory().toString()+"/YOURFOLDER"+"/yourfilename.formatextension"; // your custom pathare to use the file format and directory you used when saving
mp.prepare();
mp.start();
Hope this answer helps!

Android: How to record mp3 radio (audio) stream

My favorite Radio station plays a radio audio stream in mp3 format. In my android application I can receive and play it without any problem.
How can I implement a recording function? I want to record the mp3 radio stream to my Android phones SD-Card.
I tried the MediaRecorder Class without any result...
Android Developer: MediaRecorder
...
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.DEFAULT);
...
Unfortunately I cannot choose something like:
mRecorder.setAudioSource(MediaRecorder.AudioSource.MP3_STREAM); ... ;-)
How can I record a mp3 radio stream? Thanks for any help or code snippets...

Perfect! Reading the audio stream "byte by byte" is the solution. Thank you!!
Here my code snippets:
URL url = new URL("http://myradio,com/stream.mp3");
inputStream = url.openStream();
Log.d(LOG_TAG, "url.openStream()");
fileOutputStream = new FileOutputStream(outputSource);
Log.d(LOG_TAG, "FileOutputStream: " + outputSource);
int c;
while ((c = inputStream.read()) != -1) {
Log.d(LOG_TAG, "bytesRead=" + bytesRead);
fileOutputStream.write(c);
bytesRead++;
}

Maybe you should read audio stream "byte by byte" and then place it into new file? Like a simple file copy operation, using inputstream-outputstream.

audio recording in android

I have and android emulator and microphone connected to my pc. I want to capture pcm pulses from microphone (i.e. record voice) and then send to udp socket. please anybody help me in source code at least for voice recording.

You can use this code for your audio recording:
MediaRecorder recorder;
void startRecording() throws IOException
{
SimpleDateFormat timeStampFormat = new SimpleDateFormat(
"yyyy-MM-dd-HH.mm.ss");
String fileName = "audio_" + timeStampFormat.format(new Date())
+ ".mp4";
recorder = new MediaRecorder();
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
recorder.setOutputFile("/sdcard/"+fileName);
recorder.prepare();
recorder.start();
}
protected void stopRecording() {
recorder.stop();
recorder.release();
}

Check Audalyzer, a sample application showing you how to read the raw audio stream from the microphone on real time.

Android Record Audio issue

I found the code to record audio, but I always get:
The method setOutputFile(FileDescriptor) in the type MediaRecorder is not applicable for the arguments (Uri)
So how would I need to describe the filepath that it works?
// Prepare recorder source and type
MediaRecorder recorder = new MediaRecorder();
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
// File to which audio should be recorded
File outputFile = getFileStreamPath("output.amr");
Uri target = Uri.parse(outputFile.getAbsolutePath());
recorder.setOutputFile(target);
// Get ready!
recorder.prepare();
// Start recording
recorder.start();
// Stop and tidy up
recorder.stop();
recorder.release();

You're trying to pass in an Uri as parameter to the method which doesn't expect that.
Just replace recorder.setOutputFile(target) with:
recorder.setOutputFile(outputFile.getAbsolutePath());
That should work since string parameter is allowed.

Streaming AAC audio with Android

As I understand it, Android will only play AAC format audio if it's encoded as MPEG-4 or 3GPP.
I'm able to play AAC audio encoded as M4A when it's local to the app, but it fails when obtaining it from a server.
The following works, as the m4a file is held locally in the res/raw directory.
MediaPlayer mp = MediaPlayer.create(this, R.raw.*file*);
mp.start();
The following doesn't work. (But does with MP3's).
Uri uri = Uri.parse("http://*example.com*/blah.m4a");
MediaPlayer mp = MediaPlayer.create(this, uri);
mp.start();
Can anyone shed any light on why it fails when the m4a audio file is not local?
Here's (some of) the error...
ERROR/PlayerDriver(542): Command PLAYER_INIT completed with an error or info UNKNOWN PVMFStatus
ERROR/MediaPlayer(769): error (200, -32)
WARN/PlayerDriver(542): PVMFInfoErrorHandlingComplete
DEBUG/MediaPlayer(769): create failed:
DEBUG/MediaPlayer(769): java.io.IOException: Prepare failed.: status=0xC8
DEBUG/MediaPlayer(769): at android.media.MediaPlayer.prepare(Native Method)
DEBUG/MediaPlayer(769): at android.media.MediaPlayer.create(MediaPlayer.java:530)
DEBUG/MediaPlayer(769): at android.media.MediaPlayer.create(MediaPlayer.java:507)
...
I'm targeting SDK 1.6.

This work-around allows you to play M4A files from the net (and AAC files in other containers such as MP4 & 3GP). It simply downloads the file and plays from the cache.
private File mediaFile;
private void playAudio(String mediaUrl) {
try {
URLConnection cn = new URL(mediaUrl).openConnection();
InputStream is = cn.getInputStream();
// create file to store audio
mediaFile = new File(this.getCacheDir(),"mediafile");
FileOutputStream fos = new FileOutputStream(mediaFile);
byte buf[] = new byte[16 * 1024];
Log.i("FileOutputStream", "Download");
// write to file until complete
do {
int numread = is.read(buf);
if (numread <= 0)
break;
fos.write(buf, 0, numread);
} while (true);
fos.flush();
fos.close();
Log.i("FileOutputStream", "Saved");
MediaPlayer mp = new MediaPlayer();
// create listener to tidy up after playback complete
MediaPlayer.OnCompletionListener listener = new MediaPlayer.OnCompletionListener() {
public void onCompletion(MediaPlayer mp) {
// free up media player
mp.release();
Log.i("MediaPlayer.OnCompletionListener", "MediaPlayer Released");
}
};
mp.setOnCompletionListener(listener);
FileInputStream fis = new FileInputStream(mediaFile);
// set mediaplayer data source to file descriptor of input stream
mp.setDataSource(fis.getFD());
mp.prepare();
Log.i("MediaPlayer", "Start Player");
mp.start();
} catch (Exception e) {
e.printStackTrace();
}
}

I tried it too but I could not find out the solution!
At the last Google I/O I saw something that helped me a lot. It is Extending from MediaPlayer and improve a lot of things! Take a look.
EXOPLAYER CAN HELP YOU A LOT
Check this part of the example:
private static final int BUFFER_SEGMENT_SIZE = 64 * 1024;
private static final int BUFFER_SEGMENT_COUNT = 256;
...
// String with the url of the radio you want to play
String url = getRadioUrl();
Uri radioUri = Uri.parse(url);
// Settings for exoPlayer
Allocator allocator = new DefaultAllocator(BUFFER_SEGMENT_SIZE);
String userAgent = Util.getUserAgent(context, "ExoPlayerDemo");
DataSource dataSource = new DefaultUriDataSource(context, null, userAgent);
ExtractorSampleSource sampleSource = new ExtractorSampleSource(
radioUri, dataSource, allocator, BUFFER_SEGMENT_SIZE * BUFFER_SEGMENT_COUNT);
audioRenderer = new MediaCodecAudioTrackRenderer(sampleSource);
// Prepare ExoPlayer
exoPlayer.prepare(audioRenderer);
EXOPLAYER- I can play anything from streamings (video and audio)!
LET ME KNOW IF YOU NEED HELP TO IMPLEMENT IT! :)

This is a wild shot in the dark, but I have seen similar behavior with the flash player where it actually ignores the file name and only relies on the MIME type sent by the server. Any idea what headers are being sent down from example.com? You might want to try wrapping your blah.m4a in a page that can set the headers and then stream the binary data. Give these types a shot and the community would appreciate a confirmation of what works:
audio/mpeg
audio/mp4a
audio/mp4a-latm
audio/aac
audio/x-aac

I found that if you record the audio file on Android with the following properties, you are then able to play it on your server. It also plays well in the HTML Audio Element, however only on Firefox at the moment. This may change in the future.
Android (JAVA):
mediaRecorder = new MediaRecorder();
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.HE_AAC);
mediaRecorder.setAudioSamplingRate(44100);
mediaRecorder.setAudioChannels(1);
mediaRecorder.setOutputFile(filePath);
HTML:
<audio id="audioMediaControl" controls src="yourfile.m4a"> Your browser does not support the audio element. </audio>

try --
1) MP.prepareAsync()
2) onPrepared() { mp.start() }