I am making an app where I need to read continues stream of sound which is sent in the form of an byte array. The server side records sound like this (based on an example here on SO):
// Get the minimum buffer size required for the successful creation of an AudioRecord object.
int bufferSizeInBytes = AudioRecord.getMinBufferSize(RECORDER_SAMPLERATE, RECORDER_CHANNELS,
RECORDER_AUDIO_ENCODING);
bufferSizeInBytes = 30000;
// Initialize Audio Recorder.
_audio_recorder = new AudioRecord(MediaRecorder.AudioSource.MIC, RECORDER_SAMPLERATE,
RECORDER_CHANNELS, RECORDER_AUDIO_ENCODING, bufferSizeInBytes);
// Start Recording.
_audio_recorder.startRecording();
int numberOfReadBytes = 0;
byte audioBuffer[] = new byte[bufferSizeInBytes];
boolean recording = false;
float tempFloatBuffer[] = new float[3];
int tempIndex = 0;
byte totalByteBuffer[] = new byte[60 * 44100 * 2];
while (true)
{
float totalAbsValue = 0.0f;
short sample = 0;
numberOfReadBytes = _audio_recorder.read(audioBuffer, 0, bufferSizeInBytes);
for (int i = 0; i < bufferSizeInBytes; i += 2)
{
sample = (short) ((audioBuffer[i]) | audioBuffer[i + 1] << 8);
totalAbsValue += Math.abs(sample) / (numberOfReadBytes / 2);
}
tempFloatBuffer[tempIndex % 3] = totalAbsValue;
float temp = 0.0f;
for (int i = 0; i < 3; ++i)
temp += tempFloatBuffer[i];
if ((temp >= 0 && temp <= _sensitivity) && recording == false)
{
Log.i("TAG", "1");
tempIndex++;
continue;
}
if (temp > _sensitivity && recording == false)
{
Log.i("TAG", "2");
recording = true;
}
if(temp < _sensitivity && recording == true)
{
recording = false;
continue;
}
for (int i = 0; i < numberOfReadBytes; i++)
totalByteBuffer[i] = audioBuffer[i];
if (prepare_sound(totalByteBuffer, numberOfReadBytes))
{
totalByteBuffer = new byte[60 * 44100 * 2];
tempIndex++;
}
}
The example this is taken from is recording sound and saves it to a file when there is no more sound to record. My goal on the other hand is to record sound when there is sound and send this sound on the fly when still recording. Hence, I want to send sounds right a way and not store it to a file when there is no more sound to record. So far I am taking the byte[] with data and stores it in an object an sends it to a client using ObjectOutputStream. The client will then create a temp sound file and play it using MediaPlayer. But I feel that this is not the most effect way to achieve my goal. So, is there any more efficient way to do this with respect to send an continues stream of data as media player does not support playing pure byte[] of data?
Thanks for any help and tips!
Found out that the best solutions for me is to record the sound and when the buffer is full it is sent to the client side. The client then uses an AudioTrack instance to play the byte[] that contains the data like this:
public void onSoundReceived(byte[] sound)
{
_audio_input_stream.write(sound, 0, sound.length);
}
This also makes the sound more "non-lagging" as this is not a MediaPlayer instance which will stop the sound after each time the data was done playing.
Related
In my app I generate list of sounds with different frequencies, for example 1000Hz, 2000Hz, 4000Hz ... for left and right channel:
private AudioTrack generateTone(Ear ear) {
// fill out the array
int numSamples = SAMPLE_RATE * getDurationInSeconds();
double[] sample = new double[numSamples];
byte[] generatedSnd = new byte[2 * numSamples];
for (int i = 0; i < numSamples; ++i) {
sample[i] = Math.sin(2 * Math.PI * i / (SAMPLE_RATE / getLatestFreqInHz()));
}
// convert to 16 bit pcm sound array
// assumes the sample buffer is normalised.
int idx = 0;
for (final double dVal : sample) {
// scale to maximum amplitude
final short val = (short) ((dVal * 32767));
// in 16 bit wav PCM, first byte is the low order byte
generatedSnd[idx++] = (byte) (val & 0x00ff);
generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
}
AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
SAMPLE_RATE, AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT, numSamples,
AudioTrack.MODE_STATIC);
audioTrack.write(generatedSnd, 0, generatedSnd.length);
int channel;
if (ear == Ear.LEFT) {
audioTrack.setStereoVolume(1.0f, 0.0f);
} else if (ear == Ear.RIGHT) {
audioTrack.setStereoVolume(0.0f, 1.0f);
}
return audioTrack;
}
I use this code to control volume:
audioManager = (AudioManager) context.getApplicationContext().getSystemService(Context.AUDIO_SERVICE);
MAX_VOLUME = audioManager.getStreamMaxVolume(STREAM_MUSIC);
MIN_VOLUME = audioManager.getStreamMinVolume(STREAM_MUSIC);
APP_DEFAULT_VOLUME = (MAX_VOLUME + MIN_VOLUME) /2 ;
#Override
public void setToAppDefaultVolume() {
Timber.tag(TAG).d("Resetting to app default sound volume.");
audioManager.setStreamVolume(STREAM_MUSIC, APP_DEFAULT_VOLUME, 0);
}
#Override
public void increaseVolume() {
if (!isReachedMaxVolume()) {
Timber.tag(TAG).d("Increasing device sound volume from %d to %d", currentVolumeLevel(), currentVolumeLevel() + STEP);
audioManager.setStreamVolume(STREAM_MUSIC, currentVolumeLevel() + STEP, 0);
} else {
Timber.tag(TAG).d("Reached the maximum device volume.");
}
}
#Override
public void decreaseVolume() {
if (!isReachedMinVolume()) {
Timber.tag(TAG).d("Decreasing device sound volume from %d to %d", currentVolumeLevel(), currentVolumeLevel() - STEP);
audioManager.setStreamVolume(STREAM_MUSIC, currentVolumeLevel() - STEP, 0);
} else {
Timber.tag(TAG).d("Reached the preferred minimum volume");
}
}
I start playing each tone (frequency) with APP_DEFAULT_VOLUME and gradually increase tone. When user confirm he/she heard specific tone with specific volume, I want to calculate it's amplitude and log it for latter so I can review user hearing ...
But i have no clue how to do so!
All solutions I found was about reading data from microphone and calculate the amplitude to visualize it on screen ...
My scenario is much simpler. I have device volume recorded, frequency is fixed and recorded, and Audio is generated dynamically and is not a file.
Will anyone help me with this scenario ?
Thanks in advance.
I have a problem to generate smooth sinus wave.
I've done it few years ago on C++ and everything worked perfect. Now I am trying to do this using AudioTrack and I do not know what is wrong.
This is my test case:
I want to produce for five second a sinus wave which is smooth (no crack etc.). For one second I generate 44100 samples and divided it on couple of buffer with size 8192 (probably this is the reason of cracks, but how can I fix it, without giving bigger size of buffer).
Unfortunatelly using my code the sound is not smooth and instead of 5 second it takes about 1 second. I would be gratefull for any help.
Please let me now if this piece of code is not enough.
class Constants:
//<---
public final static int SAMPLING = 44100;
public final static int DEFAULT_GEN_DURATION = 1000;
public final static int DEFAULT_NUM_SAMPLES = DEFAULT_GEN_DURATION * SAMPLING / 1000; //44100 per second
public final static int DEFAULT_BUFFER_SIZE = 8192;
//--->
//preparing buffers to play;
Buffer buffer = new Buffer();
short[] buffer_values = new short[Constants.DEFAULT_BUFFER_SIZE];
float[] samples = new float[Constants.DEFAULT_BUFFER_SIZE];
float d = (float) (( Constants.FREQUENCIES[index] * 2 * Math.PI ) / Constants.SAMPLING);
int numSamples = Constants.DEFAULT_NUM_SAMPLES; //44100 per second - for test
float x = 0;
int index_in_buffer = 0;
for(int i = 0; i < numSamples; i++){
if(index_in_buffer >= Constants.DEFAULT_BUFFER_SIZE - 1){
buffer.setBufferShort(buffer_values);
buffer.setBufferSizeShort(index_in_buffer);
queue_with_data_AL.add(buffer); //add buffer to queue
buffer_values = new short[Constants.DEFAULT_BUFFER_SIZE];
samples = new float[Constants.DEFAULT_BUFFER_SIZE];
index_in_buffer = 0;
}
samples[index_in_buffer] = (float) Math.sin(x);
buffer_values[index_in_buffer] = (short) (samples[index_in_buffer] * Short.MAX_VALUE);
x += d;
index_in_buffer++;
}
buffer.setBufferShort(buffer_values);
buffer.setBufferSizeShort(index_in_buffer+1);
queue_with_data_AL.add(buffer);
index_in_buffer = 0;
}
//class AudioPlayer
public AudioPlayer(int sampleRate) { //44100
int minSize = AudioTrack.getMinBufferSize(sampleRate,
AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
audiotrack = new AudioTrack(AudioManager.STREAM_MUSIC, sampleRate,
AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT,
minSize, AudioTrack.MODE_STREAM);
}
public void play(byte[] audioData, int sizeOfBuffer) {
audiotrack.write(audioData, 0, sizeOfBuffer);
}
public void start() {
if (state == Constants.STOP_STATE) {
state = Constants.START_STATE;
int startLength = 0;
while (state == Constants.START_STATE) {
Buffer buffer = getBufferFromQueueAL(); //getting buffer from prepared list
if (buffer != null) {
short[] data = buffer.getBufferShort();
int size_of_data = buffer.getBufferSizeShort();
if (data != null) {
int len = audiotrack.write(data, 0, size_of_data);
if (startLength == 0) {
audiotrack.play();
}
startLength += len;
} else {
break;
}
} else {
MessagesLog.e(TAG, "get null data");
break;
}
}
if (audiotrack != null) {
audiotrack.pause();
audiotrack.flush();
audiotrack.stop();
}
}
}
You are playing only 1 second because 44100 samples at a samplerate of 44100Hz result in exactly 1 second of sound.
You have to generate 5 times more samples if you want to play 5 seconds of sound (e.g. multiply DEFAULT_NUM_SAMPLES by 5) in your code.
I've found the solution by myself. After adding Buffer to queue_with_data_AL I've forgotten create new instance of Buffer object. So in queue was couple of buffer with the same instance, hence sinus wave were not continuous.
Thanks if someone was trying to solve my problem. Unfortunatelly it was my programming mistake.
Best regards.
My goal is to obtain the rpm of powerballs by analysing sound generated during ball rotation. In google play, several application available to calculate rpm and frequency by sound but each and every app failed to find out rpm of power balls. I searched on google and found that "To calculate frequency from sound, we have to use FFT Algo".
what is power ball?
Powerball rotate and generate sound.
"Powerball® generates resistance which is directly in proportion to the effort expended by the user".
class RecorderThread1 extends Thread {
private static final String TAG = RecorderThread1.class.getSimpleName();
public boolean recording; // variable to start or stop recording
public int frequency; // the public variable that contains the frequency
private PlaceholderFragment placeHolder;
private Handler handler;
private long avgFrequency;
private int avg = 0;
private int sampelRateHz = 8000;
// value "heard", it is updated continually while
// the thread is running.
public RecorderThread1(PlaceholderFragment placeHolder) {
this.placeHolder = placeHolder;
}
#Override
public void run() {
AudioRecord recorder;
int numCrossing, p;
short audioData[];
int bufferSize;
bufferSize = AudioRecord.getMinBufferSize(8000,
AudioFormat.CHANNEL_CONFIGURATION_MONO,
AudioFormat.ENCODING_PCM_16BIT) * 3; // get the buffer size to
// use with this audio
// record
recorder = new AudioRecord(AudioSource.MIC, 8000,
AudioFormat.CHANNEL_CONFIGURATION_MONO,
AudioFormat.ENCODING_PCM_16BIT, bufferSize); // instantiate the
// AudioRecorder
recording = true; // variable to use start or stop recording
audioData = new short[bufferSize]; // short array that pcm data is put
// into.
while (recording) { // loop while recording is needed
if (recorder.getState() == android.media.AudioRecord.STATE_INITIALIZED) // check
// to
// see
// if
// the
// recorder
// has
// initialized
// yet.
if (recorder.getRecordingState() == android.media.AudioRecord.RECORDSTATE_STOPPED)
recorder.startRecording(); // check to see if the Recorder
// has stopped or is not
// recording, and make it
// record.
else {
recorder.read(audioData, 0, bufferSize); // read the PCM
// audio data
// into the
// audioData
// array
// Now we need to decode the PCM data using the Zero
// Crossings Method
numCrossing = 0; // initialize your number of zero crossings
// to 0
for (p = 0; p 0 && audioData[p + 1] = 0)
numCrossing++;
if (audioData[p + 1] > 0 && audioData[p + 2] = 0)
numCrossing++;
if (audioData[p + 2] > 0 && audioData[p + 3] = 0)
numCrossing++;
if (audioData[p + 3] > 0 && audioData[p + 4] = 0)
numCrossing++;
}// for p
for (p = (bufferSize / 4) * 4; p 0 && audioData[p + 1] = 0)
numCrossing++;
}
frequency = (8000 / bufferSize) * (numCrossing / 2); // Set
// the audio Frequency to half the number of zero crossings, times the number of samples our buffersize is per second.
avgFrequency = avgFrequency + frequency;
avg++;
Log.d(TAG, " frequency is " + frequency);
if (handler == null) {
handler = new Handler(Looper.getMainLooper());
handler.postDelayed(runnable, 2000);
}
// placeHolder.printFrequency((frequency * 60));
}// else recorder started
} // while recording
The number of zero crossing will not be reliable, higher and lower frequencies will add noise, unless the sound is a pure sinus or square wave.
You can find and FFT algorithm there: FFT library in android Sdk
FFT is computing the power in frequency bands (as a spectrum analyzer would display). You should try to look at the curve image from the powerball sound, and decide which is the best way to handle it (lower frequency peak, higher value peak, ...).
Below is the code for my play() method which simply generates an arbitrary set of frequencies and blends them into one tone.
The problem is that it only plays for a split second - I need is to play it continuously. I would appreciate suggestions on how to constantly generate the sound using the AudioTrack class in Android. I believe it has something to do with the MODE_STREAM constant, but I can't quite work out how.
Here is the link to AudioTrack class documentation:
http://developer.android.com/reference/android/media/AudioTrack.html
EDIT: I forgot to mention one important aspect, it can't loop. Due to the mixing of sometimes up to 50+ frequencies, it will sound choppy because there is no least common denominator for all frequency peaks - or it's too far down the waveform to store as one sound.
/**
* play - begins playing the sound
*/
public void play() {
// Get array of frequencies with their relative strengths
double[][] soundData = getData();
// Track samples array
final double samples[] = new double[1024];
// Calculate the average sum in the array and write it to sample
for (int i = 0; i < samples.length; ++i) {
double valueSum = 0;
for (int j = 0; j < soundData.length; j++) {
valueSum += Math.sin(2 * Math.PI * i / (SAMPLE_RATE / soundData[j][0]));
}
samples[i] = valueSum / soundData.length;
}
// Obtain a minimum buffer size
int minBuffer = AudioTrack.getMinBufferSize(SAMPLE_RATE, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
if (minBuffer > 0) {
// Create an AudioTrack
mTrack = new AudioTrack(AudioManager.STREAM_MUSIC, SAMPLE_RATE, AudioFormat.CHANNEL_CONFIGURATION_MONO,
AudioFormat.ENCODING_PCM_16BIT, minBuffer, AudioTrack.MODE_STREAM);
// Begin playing track
mTrack.play();
// Fill the buffer
if (mBuffer.length < samples.length) {
mBuffer = new short[samples.length];
}
for (int k = 0; k < samples.length; k++) {
mBuffer[k] = (short) (samples[k] * Short.MAX_VALUE);
}
// Write audio data to track for real-time audio sythesis
mTrack.write(mBuffer, 0, samples.length);
}
// Once everything has successfully begun, indicate such.
isPlaying = true;
}
It looks like the code is almost there. It just needs a loop to keep generating the samples, putting them in the buffer, and writing them to the AudioTrack. Right now just one buffer full gets written before it exits which is why it stops so quickly.
void getSamples(double[] samples) {
// Get array of frequencies with their relative strengths
double[][] soundData = getData();
// Calculate the average sum in the array and write it to sample
for (int i = 0; i < samples.length; ++i) {
double valueSum = 0;
for (int j = 0; j < soundData.length; j++) {
valueSum += Math.sin(2 * Math.PI * i / (SAMPLE_RATE / soundData[j][0]));
}
samples[i] = valueSum / soundData.length;
}
}
public void endPlay() {
done = true;
}
/**
* play - begins playing the sound
*/
public void play() {
// Obtain a minimum buffer size
int minBuffer = AudioTrack.getMinBufferSize(SAMPLE_RATE, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
if (minBuffer > 0) {
// Create an AudioTrack
mTrack = new AudioTrack(AudioManager.STREAM_MUSIC, SAMPLE_RATE, AudioFormat.CHANNEL_CONFIGURATION_MONO,
AudioFormat.ENCODING_PCM_16BIT, minBuffer, AudioTrack.MODE_STREAM);
// Begin playing track
mTrack.play();
// Track samples array
final double samples[] = new double[1024];
while (!done) {
// Fill the buffer
if (mBuffer.length < samples.length) {
mBuffer = new short[samples.length];
}
getSamples(samples);
for (int k = 0; k < samples.length; k++) {
mBuffer[k] = (short) (samples[k] * Short.MAX_VALUE);
}
// Write audio data to track for real-time audio sythesis
mTrack.write(mBuffer, 0, samples.length);
// Once everything has successfully begun, indicate such.
isPlaying = true;
}
}
// Once everything is done, indicate such.
isPlaying = false;
}
I using AudioTrack in static mode to reproduce the same signal over and over again.
I have followed the example in here and sometimes it works perfectly, but sometimes it throws this error and it produces no sound:
AudioTrack: start called from a thread
01-23 15:26:16.902: W/libutils.threads(1133): Thread (this=0x3973b8): don't call waitForExit() from this Thread object's thread. It's a guaranteed deadlock!
This is the source code. I'm trying to ensure that I call stop and reload the data for the next "play" execution.
public class SoundPlayer {
// originally from http://marblemice.blogspot.com/2010/04/generate-and-play-tone-in-android.html
private int numSamples;
private double sample[];
private byte generatedSnd[];
private AudioTrack audioTrack;
public SoundPlayer(float duration, int sampleRate, double freqOfTone) {
super();
this.numSamples = (int) (duration * sampleRate);
this.sample = new double[numSamples];
this.generatedSnd = new byte[2 * numSamples];
// fill out the array
for (int i = 0; i < numSamples; ++i) {
sample[i] = Math.sin(2 * Math.PI * i / (sampleRate / freqOfTone));
}
// convert to 16 bit pcm sound array
// assumes the sample buffer is normalised.
int idx = 0;
for (final double dVal : sample) {
// scale to maximum amplitude
final short val = (short) ((dVal * 32767));
// in 16 bit wav PCM, first byte is the low order byte
generatedSnd[idx++] = (byte) (val & 0x00ff);
generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
}
audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
sampleRate, AudioFormat.CHANNEL_CONFIGURATION_MONO,
AudioFormat.ENCODING_PCM_16BIT, numSamples,
AudioTrack.MODE_STATIC);
audioTrack.write(generatedSnd, 0, generatedSnd.length);
}
public void playSound() {
if ( audioTrack.getPlayState() == (AudioTrack.PLAYSTATE_PLAYING | AudioTrack.PLAYSTATE_PAUSED )) {
audioTrack.stop();
audioTrack.reloadStaticData();
}
Log.i("Audio", "playState: " + audioTrack.getPlayState());
audioTrack.play();
audioTrack.stop();
audioTrack.reloadStaticData();
}
}
If we open the android source code, it does not explains a lot:
void AudioTrack::start()
{
sp<AudioTrackThread> t = mAudioTrackThread;
LOGV("start");
if (t != 0) {
if (t->exitPending()) {
if (t->requestExitAndWait() == WOULD_BLOCK) {
LOGE("AudioTrack::start called from thread");
return;
}
}
t->mLock.lock();
}
Does anyone know how to handle this?
I had a similar problem once.
Simply put, if you happen to have stuff running in more than one thread you have to make sure that creating the AudioTrack and calling play() and stop() on it must happen in the same thread.
However, it doesn't mean that you have to create the audio samples in that thread, too. In case you use static audio data (AudioTrack.MODE_STATIC) you can preload or generate them elsewhere and then use it even multiple times throughout the lifetime of your app.