如何创建连续运行调谐器？ [英] How to create tuner that runs continuously?
问题描述
我创建为Android调谐器（类似于吉他调谐器），我想知道如何让调谐器连续运行（一两分钟左右）。我不希望它在后台运行，只是当用户在我的应用程序的服务。
I am creating a tuner for Android (similar to a guitar tuner) and I am wondering how to allow the tuner to run continuously (for a couple minutes or so). I don't want it to be a service that runs in the background, just while the user is in my app.
我已经成功地使用了 AudioRecord 类和我获得这似乎正确的数据。我在过滤该数据，并找到输入信号的基本频率的过程中，但需要帮助找出如何让我的调谐器连续地运行。
I have successfully used the AudioRecord class and am obtaining data that seems correct. I am in the process of filtering this data and finding the fundamental frequency of the input signal, but need help figuring out how to allow my tuner to run continuously.
这是我的code样子至今：
This is what my code looks like so far:
import android.app.Activity;
import android.graphics.Color;
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.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import com.dustin.tuner2.FFT;
import com.dustin.tuner2.Complex;
public class Tuner2 extends Activity implements OnClickListener {
Button btnTune;
TextView fft;
TextView freq;
TextView results;
MediaRecorder recorder;
AudioRecord tuner;
boolean startTuning = true;
int audioSource = MediaRecorder.AudioSource.MIC;
int sampleRateInHz = AudioTrack.getNativeOutputSampleRate(AudioManager.STREAM_SYSTEM);
int channelConfig = AudioFormat.CHANNEL_CONFIGURATION_MONO;
int audioFormat = AudioFormat.ENCODING_PCM_16BIT;
int bufferSizeInBytes;
int samples;
short[] audioBuffer;
short[] audioData;
double[] temp;
String fileName;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btnTune = (Button)findViewById(R.id.btnTune);
freq = (TextView)findViewById(R.id.freq);
btnTune.setOnClickListener(this);
bufferSizeInBytes = 4096;
//bufferSizeInBytes = AudioRecord.getMinBufferSize(sampleRateInHz, channelConfig, audioFormat);
results = (TextView)findViewById(R.id.results);
fft = (TextView)findViewById(R.id.fft);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (v == btnTune)
{
onTune(startTuning);
if (startTuning) {
((Button)v).setText("Stop Tuning");
}
else {
((Button)v).setText("Start Tuninig");
}
startTuning = !startTuning;
}
}
//------------------------------------------------------------>
private void onTune(boolean start) {
if(start) {
startTuning();
} else {
Toast.makeText(getApplicationContext(), "Tuning Stopped", Toast.LENGTH_SHORT).show();
tuner.stop();
}
}
private void startTuning()
{
tuner = new AudioRecord(audioSource, sampleRateInHz, channelConfig, audioFormat, bufferSizeInBytes);
audioData = new short[bufferSizeInBytes];
trigger();
}
public void trigger(){
acquire();
computeFFT();
display();
}
public void acquire(){
try {
tuner.startRecording();
samples = tuner.read(audioData, 0, bufferSizeInBytes);
}
catch (Throwable t){
}
}
public void computeFFT(){
//Conversion from short to double
double[] micBufferData = new double[bufferSizeInBytes];//size may need to change
final int bytesPerSample = 2; // As it is 16bit PCM
final double amplification = 100.0; // choose a number as you like
for (int index = 0, floatIndex = 0; index < bufferSizeInBytes - bytesPerSample + 1; index += bytesPerSample, floatIndex++) {
double sample = 0;
for (int b = 0; b < bytesPerSample; b++) {
int v = audioData[index + b];
if (b < bytesPerSample - 1 || bytesPerSample == 1) {
v &= 0xFF;
}
sample += v << (b * 8);
}
double sample32 = amplification * (sample / 32768.0);
micBufferData[floatIndex] = sample32;
}
//Create Complex array for use in FFT
Complex[] fftTempArray = new Complex[bufferSizeInBytes];
for (int i=0; i<bufferSizeInBytes; i++)
{
fftTempArray[i] = new Complex(micBufferData[i], 0);
}
//Obtain array of FFT data
final Complex[] fftArray = FFT.fft(fftTempArray);
final Complex[] fftInverse = FFT.ifft(fftTempArray);
//Create an array of magnitude of fftArray
double[] magnitude = new double[fftArray.length];
for (int i=0; i<fftArray.length; i++){
magnitude[i]= fftArray[i].abs();
}
fft.setTextColor(Color.GREEN);
fft.setText("fftArray is "+ fftArray[500] +" and fftTempArray is "+fftTempArray[500] + " and fftInverse is "+fftInverse[500]+" and audioData is "+audioData[500]+ " and magnitude is "+ magnitude[1] + ", "+magnitude[500]+", "+magnitude[1000]+" You rock dude!");
for(int i = 2; i < samples; i++){
fft.append(" " + magnitude[i] + " Hz");
}
}
public void display(){
results.setTextColor(Color.BLUE);
results.setText(audioData[1]+"");
for(int i = 2; i < samples; i++){
results.append(" " + audioData[i]);
}
results.invalidate();
//fft.setTextColor(Color.GREEN);
//fft.setText("Buffer size is "+bufferSizeInBytes);
//fft.setText(fftArray[1]+" Hz");
//for(int i = 2; i < samples; i++){
//fft.append(" " + fftArray[i] + " Hz");
//}
//fft.invalidate();
}
我是否需要改变有关按钮，并在pressed它做了什么事？它只是涉及到缓冲区的大小？我多久计算FFT？
Do I need to change something concerning the button and what it does when pressed? Would it just involve the buffer size? How often I compute the FFT?
推荐答案
除非我误解，你可以只使用一个while循环，检查一个布尔变量。当用户点击停止按钮变量设置为false。
Unless I am misunderstanding, you could just use a while loop that checks a boolean variable. When the user clicks the stop button set that variable to false.
while (tuning) {
trigger();
}
您也应该可能引入这些调用之间的延迟。这也将是明智的运行比在UI线程的线程上该code。请参见 http://developer.android.com/resources/articles/painless-threading。 HTML
you should also probably introduce a delay between these calls. It would also be wise to run this code on a thread other than the UI thread. See http://developer.android.com/resources/articles/painless-threading.html
我的意思一个简单的例子是做
A simple example of what I mean would be to do
new Thread(new Runnable() {
@Override
public void run() {
while (tuning) {
trigger();
try {
Thread.sleep(SLEEP_TIME_MS);
} catch (InterruptedException e) {
// handle exception
}
}
}
}).start();
但你不必担心更新，你可以这样做，从该线程的UI。最好的办法是使用的AsyncTask 的 http://developer.android.com/reference/android/os/AsyncTask.html
这篇关于如何创建连续运行调谐器？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
