Develop Reference

How to trigger Vibration on Sound Input?

I am trying to create an android application where I filter one specific frequency of a beep and make the phone vibrate.
I am taking input from the MIC of mobile and using MediaRecorder class, by using this class, I can record, save and play the input. Now I need my mobile to vibrate whenever there is a beep/or any sound.
The input is given by a wire to the Headphone jack of the mobile so I know that there is only one frequency being input.
I have a button, Clicking which starts recording.
I have Permissions to vibrate and record in my manifest file already.
record.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
isRecording=true;
myAudioRecorder.prepare();
myAudioRecorder.start();
...
}
I also tried to search the internet and found kind of the similar question here but I am unable to find any correct answer.
However, I can make the phone vibrate on clicking another button and here is the snipt of code,
Vibrator vibrate;
vibrate = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
Btn1.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v) {
vibrate.vibrate(800);
}
}
I tried calling a Vibrator inside recorder.start(); function but this makes the phone vibrate even when there is no sound anymore.
I also tried getting help from this question so whenever there is silence, the phone should not vibrate, but I am getting confused, I somehow understand that there should be a Boolean which gets true when there is sound and make the phone vibrate, but I am unable to put this logic into code.
Please let me know what can I do in this context and which direction should I be searching in?
UPDATE
I found this toturial for showing the progress bar with amplitude of input sound, it works fine and I tried to make the phone vibrate when there is some value in buffer, Now it vibrates even when the amplitude is zero, I guess thats because of the fact that every vibration makes noise which leads the phone to vibrate. I am unable to check the function via TOAST because of java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare(). Is there any suggestion?

For your main problem, maybe you can check for the amplitude of the sound, and only vibrate if a minimum threshold has been reached. Something like this:
private class DetectAmplitude extends AsyncTask<Void, Void, Void> {
private MediaRecorder mRecorder = null;
private final static int MAX_AMPLITUDE = 32768;
//TODO: Investigate what is the ideal value for this parameter
private final static int MINIMUM_REQUIRED_AVERAGE = 5000;
#Override
protected Void doInBackground(Void... params) {
Boolean soundStarted = true;
if (mRecorder == null) {
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mRecorder.setOutputFile("/dev/null");
try {
mRecorder.prepare();
} catch (IllegalStateException e) {
soundStarted = false;
Log.e(TAG, "Could not detect background noise. Error preparing recorder: " + e.getMessage());
} catch (IOException e) {
soundStarted = false;
Log.e(TAG, "Could not detect background noise. Error preparing recorder: " + e.getMessage());
}
try {
mRecorder.start();
} catch (RuntimeException e) {
Log.e(TAG, "Could not detect background noise. Error starting recorder: " + e.getMessage());
soundStarted = false;
mRecorder.release();
mRecorder = null;
}
}
if (soundStarted) {
// Compute a simple average of the amplitude over one
// second
int nMeasures = 100;
int sumAmpli = 0;
mRecorder.getMaxAmplitude(); // First call returns 0
int n = 0;
for (int i = 0; i < nMeasures; i++) {
if (mRecorder != null) {
int maxAmpli = mRecorder.getMaxAmplitude();
if (maxAmpli > 0) {
sumAmpli += maxAmpli;
n++;
}
} else {
return null;
}
try {
Thread.sleep(1000 / nMeasures);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
mRecorder.stop();
mRecorder.release();
mRecorder = null;
final float avgAmpli = (float) sumAmpli / n;
if (avgAmpli > MINIMUM_REQUIRED_AVERAGE) {
//TODO: Vibrate the device here
}
}
return null;
}
}
For more information regarding the detection of sound level, please refer to the following:
android: detect sound level
What does Android's getMaxAmplitude() function for the MediaRecorder actually give me?
Regarding the exception java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare(), that is happening because the Toast needs to run on the main thread of your app. If your Thread code (like an AsyncTask) is inside an Activity, you can try the following:
runOnUiThread(new Runnable() {
#Override
public void run() {
//Call your Toast here
}
});
Otherwise, you need to somehow pass the conclusion of your method to the Activity for it to run the Toast.
EDIT:
If you want to use this from a Button, you could set its OnClickListener on your Activity's onCreate() call and execute the AsyncTask there. For example:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.your_layout);
Button button = (Button)findViewById(R.id.your_button_id);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
new DetectAmplitude().execute(new Void[]{});
}
});
}
I suggest you take a look at how AsyncTask works before using this in production code.

You want to sample the audio, and analyze it immediately.
MediaRecorder seems to high level for this, it only captures to file. You probably want to use AudioRecorder instead, as it gives direct access to the input samples.
In order to detect a specific tone, you can use the Goertzel algorithm on the input samples. Here is a C++ implementation I did years ago that could serve as an example.
In order to detect any sound over a certain threshold, you can use Root Mean Square analysis on the input samples and make it trigger once the loudness reaches your threshold. Here is a Python example that reacts to loud noises from a microphone.

Try this:
Btn1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
v.post(new Runnable() {
#Override
public void run() {
vibrate.vibrate(800);
}
});
}
});

You can try this:
Handler handler;
Runnable r;
handler = new Handler();
r = new Runnable() {
public void run() {
Vibrator vib = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
vib.vibrate(500);
handler.postDelayed(r, 1000);
}
};
handler.post(r);

Media Player Class in Android the implementation scenario

for last three weeks I have worked on a Media Player in Android.I am trying to find a solution of how can I make my Media Player to change the song when it's already playing one.
Here is my Listener on the RecyclerView
musicList.addOnItemTouchListener(
new RecyclerItemClickListener(getApplicationContext(), new RecyclerItemClickListener.OnItemClickListener() {
#Override
public void onItemClick(View view, final int position) {
currentPosition = position;
if(!mediaPlayer.isPlaying()){
musicThread.start();
} else {
mediaPlayer.reset();
}
}
})
);
}
and my Thread is this:
final Thread musicThread = new Thread(new Runnable(){
#Override
public void run() {
try {
URL = getMusicURL(myDataset[currentPosition]);
try {
mediaPlayer.setDataSource(URL);
//mediaPlayer.prepare(); // might take long! (for buffering, etc)
mediaPlayer.prepareAsync(); // prepare async to not block main thread
} catch (IOException e) {
e.printStackTrace();
Log.i("TEST","Eroare: "+e.getMessage());
}
} catch (StorageApiException e) {
e.printStackTrace();
Log.i("TEST","Eroare: "+e.getMessage());
}
}
});

I think you have a mess. First of all, you dont need a thread to play music, the own mediaplayer API does it for you when you call mediaPlayer.start(). However, you have to care about the time it takes to prepare the data source if you are for example streaming online music. For this, just use mediaPlayer.prepareAsync() and register a callback. When it has finished preparing, you can automatically start playing or do whatever you want.
If you want to change the data source, just follow the automaton map that you can find in MediaPlayer docs. Essentially, when the user selects another track, you register the call in your button listener, then reset the mediaPlayer, and recall all prepare, start... cycle again. By the way, it is advised to deploy all your mediaplayer code into a service so that it can keep playing even though the user has closed your activity.

Service not able to run twice

I am making a music player with a service but when i click a song in the music list, the music starts with no errors, but if i go back to the list and click another i get Attempt to call getDuration without a valid mediaplayer error (-38, 0)
My onStart method in the service:
#Override
public void onStart(final Intent i, int startid) {
Log.d(TAG, "Start music");
re = 0;
songUrl = i.getData().toString();
streamMusic = new Thread() {
public void run() {
Looper.prepare();
try {
re = 1;
music.reset();
music.setDataSource(songUrl);
music.prepare();
this.interrupt();
} catch (Exception e) {
e.printStackTrace();
}
}
};
streamMusic.start();
}
I start the service with startService(i); and I have set a music.setOnPreparedListener so nothing is runned to early.
How do I make it work?

Try calling reset() method before calling prepare again.
Also, if you are calling prepare() and not prepareAsync() I don't see why you need to use the prepared listener.

Starting media player in a thread problem

I'm trying to start a media player that streams from a website. Right now, when "start" is pressed the entire activity just freezes for anywhere from 5 to 20 seconds while the stream connects. I'm trying to get the "player.start();" call to run in a thread to free up the activity while the stream connects but it's not working. Anyone have any ideas?
private void startplayer() {
try {
stream_player = new MediaPlayer();
stream_player.setAudioStreamType(AudioManager.STREAM_MUSIC);
stream_player = MediaPlayer.create(this, Uri.parse("http://stream-address"));
Thread thread = new Thread(new Runnable() {
public void run() {
stream_player.start();
}
});
thread.start();
SetNotification(1, "live");
liveON = true;
} catch (Exception e) {
Log.e(getClass().getName(), "Error starting to stream audio.", e);
Toast.makeText(this, "Stream seems to be offline", Toast.LENGTH_LONG).show();
}
}

Move the whole method to a separate thread. The part that takes the most time is the MediaPlayer.create() part, since this a synchronous call, which returns when the media player is ready to play.
An alternative is not to use create, but use the other format used in here which sets a listener before the prepare method, and when the listener is called, the start method is called.

How to detect when VideoView starts playing (Android)?

Here's the problem, I want to change play button to pause button when the video stream starts playing in videoview but I don't know how to detect that event?

There is a great article about MediaPlayer in here - http://www.malmstein.com/blog/2014/08/09/how-to-use-a-textureview-to-display-a-video-with-custom-media-player-controls/
You can set infoListener on your VideoView
setOnInfoListener(new MediaPlayer.OnInfoListener() {
#Override
public boolean onInfo(MediaPlayer mp, int what, int extra) {
if (what == MediaPlayer.MEDIA_INFO_VIDEO_RENDERING_START) {
// Here the video starts
return true;
}
return false;
}

I ended up using VideoView.setOnPreparedListener. This was enough to cover my problem (play button drawable change to pause)

accepted answer here is not 100% accurate.
sometimes onprepared is call 3 seconds before first frame is being rendered. i suggest having a callback on that event (MediaPlayer.MEDIA_INFO_VIDEO_RENDERING_START)
mMediaPlayer.setOnInfoListener(new MediaPlayer.OnInfoListener() {
#Override
public boolean onInfo(MediaPlayer mediaPlayer, int i, int i1) {
if (i == MediaPlayer.MEDIA_INFO_VIDEO_RENDERING_START){
//first frame was bufered - do your stuff here
}
return false;
}
});
see media info documantaion for more callbacks of info/warning:
https://developer.android.com/reference/android/media/MediaPlayer.html#MEDIA_INFO_VIDEO_RENDERING_START

As far as I know, there is no event sent when video start playing in VideoView, but I can think of two options:
Create a version of VideoView by yourself, that sends event in those cases.
Use MediaController (which is default in VideoView)
If you want to follow option one - you can get the source of VideoView from here

isPlaying() can be called to test whether the MediaPlayer object is in the Started
Android MediaPlayer.isPlaying()

Another way to detect if videoview started is using videoView.getCurrentPosition(). getCurrentPosition() returns 0 if streaming not started.
protected Runnable playingCheck = new Runnable() {
public void run() {
while (true) {
if (vw.getCurrentPosition() != 0) {
// do what you want when playing started
break;
} else {
try {
Thread.sleep(250);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
};
Then call:
new Thread(playingCheck).start();

Please try this :
final Handler h = new Handler();
h.postDelayed( new Runnable() {
public void run() {
if (videoView.getCurrentPosition() != 0) {
((ProgressBar) rootView.findViewById(R.id.pgStreaming)).setVisibility(View.GONE);
} else {
h.postDelayed(this, 250);
}
}
}, 250);