捕获声音进行分析和可视化的频率在Android中 [英] Capturing Sound for Analysis and Visualizing Frequencies in Android

问题描述

我是新的Andr​​oid和我试图做一个程序，它捕获音频声音，然后显示在它存在的频率。我发现，绘制图形均衡器的图形部分的一个例子。在这个例子中它是用来类型的对象 AudioRecord捕捉音频。用来向下打破的音频信号为分量频率的技术中采用了一种数学变换称为离散傅里叶变换（DFT），并执行DFT它用于一个快速傅立叶变换（FFT）。这个例子用它实现FFT包。该软件包是这里 www.netlib.org/fftpack/jfftpack.tgz 联系。 问题是，我运行这个例子后，图形均衡器不经过我preSS启动按钮出现在显示屏上。

I'm new in Android and I'm trying to make a program which captures an audio sound and then displays the frequencies that exist within it. I found an example that draws the graphic portion of a graphic equalizer. In this example it is used an object of type AudioRecord to capture audio sound. The technique used to break an audio signal down into component frequencies employs a mathematic transformation called a discrete Fourier transform (DFT) and to perform DFT it is used a fast Fourier transform (FFT). This example use a package which implements the FFT. The package is linked here www.netlib.org/fftpack/jfftpack.tgz. The problem is that after I run this example the graphic equalizer doesn't appear on the display after I press the start button.

下面是源$ C ​​$ C的活动类：

Here is the source code for the activity class:

package com.audio.processing;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

import ca.uol.aig.fftpack.RealDoubleFFT;

public class AudioProcessing extends Activity implements OnClickListener{
    int frequency = 8000;
    int channelConfiguration = AudioFormat.CHANNEL_CONFIGURATION_MONO;
    int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;


    private RealDoubleFFT transformer;
    int blockSize = 256;
    Button startStopButton;
    boolean started = false;

    RecordAudio recordTask;

    ImageView imageView;
    Bitmap bitmap;
    Canvas canvas;
    Paint paint;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        startStopButton = (Button) this.findViewById(R.id.StartStopButton);
        startStopButton.setOnClickListener(this);

        transformer = new RealDoubleFFT(blockSize);

        imageView = (ImageView) this.findViewById(R.id.ImageView01);
        bitmap = Bitmap.createBitmap((int)256,(int)100,Bitmap.Config.ARGB_8888);
        canvas = new Canvas(bitmap);
        paint = new Paint();
        paint.setColor(Color.GREEN);
        imageView.setImageBitmap(bitmap);
    }

    private class RecordAudio extends AsyncTask<Void, double[], Void> {
        @Override
        protected Void doInBackground(Void... params) {
        try {
            int bufferSize = AudioRecord.getMinBufferSize(frequency,
                    channelConfiguration, audioEncoding);
                    AudioRecord audioRecord = new AudioRecord(
                    MediaRecorder.AudioSource.DEFAULT, frequency,
                    channelConfiguration, audioEncoding, bufferSize);

                    short[] buffer = new short[blockSize];
                    double[] toTransform = new double[blockSize];
                    audioRecord.startRecording();
                    while (started) {
                    int bufferReadResult = audioRecord.read(buffer, 0, blockSize);

                    for (int i = 0; i < blockSize && i < bufferReadResult; i++) {
                        toTransform[i] = (double) buffer[i] / 32768.0; // signed 16 bit
                        }

                    transformer.ft(toTransform);
                    publishProgress(toTransform);
                    }
                    audioRecord.stop();
                    } catch (Throwable t) {
                    Log.e("AudioRecord", "Recording Failed");
                    }
                    return null;
                    }
        }

    protected void onProgressUpdate(double[]... toTransform) {
        canvas.drawColor(Color.BLACK);
        for (int i = 0; i < toTransform[0].length; i++) {
        int x = i;
        int downy = (int) (100 - (toTransform[0][i] * 10));
        int upy = 100;
        canvas.drawLine(x, downy, x, upy, paint);
        }
        imageView.invalidate();
        }

        public void onClick(View v) {
        if (started) {
        started = false;
        startStopButton.setText("Start");
        recordTask.cancel(true);
        } else {
        started = true;
        startStopButton.setText("Stop");
        recordTask = new RecordAudio();
        recordTask.execute();
        }
        }
}

下面是main.xml中：

Here is the main.xml :

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<ImageView android:id="@+id/ImageView01" android:layout_width="wrap_content"
android:layout_height="wrap_content"></ImageView><Button android:text="Start"
android:id="@+id/StartStopButton" android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
</LinearLayout>

在AndroidManifest.xml中我设置了RECORD_AUDIO权限。 在此先感谢！

In the AndroidManifest.xml I set the RECORD_AUDIO permission. Thanks in advance !

推荐答案

下面是工作code。我尝试过自己。它工作正常。

Here is the working code. I tried it myself. It works fine.

package com.example.frequencytest;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import ca.uol.aig.fftpack.RealDoubleFFT;

public class MainActivity extends Activity implements OnClickListener {

    int frequency = 8000;
    int channelConfiguration = AudioFormat.CHANNEL_CONFIGURATION_MONO;
    int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;
    private RealDoubleFFT transformer;
    int blockSize = 256;

    Button startStopButton;
    boolean started = false;

    RecordAudio recordTask;

    ImageView imageView;
    Bitmap bitmap;
    Canvas canvas;
    Paint paint;

    //AudioRecord audioRecord;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        startStopButton = (Button) this.findViewById(R.id.start_stop_btn);
        startStopButton.setOnClickListener(this);

        transformer = new RealDoubleFFT(blockSize);

        imageView = (ImageView) this.findViewById(R.id.imageView1);
        bitmap = Bitmap.createBitmap((int) 256, (int) 100,
                Bitmap.Config.ARGB_8888);
        canvas = new Canvas(bitmap);
        paint = new Paint();
        paint.setColor(Color.GREEN);
        imageView.setImageBitmap(bitmap);

    }

    public class RecordAudio extends AsyncTask<Void, double[], Void> {

        @Override
        protected Void doInBackground(Void... arg0) {

            try {
                // int bufferSize = AudioRecord.getMinBufferSize(frequency,
                // AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);
                int bufferSize = AudioRecord.getMinBufferSize(frequency, 
                        channelConfiguration, audioEncoding); 

                AudioRecord audioRecord = new AudioRecord( 
                        MediaRecorder.AudioSource.MIC, frequency, 
                        channelConfiguration, audioEncoding, bufferSize); 

                short[] buffer = new short[blockSize];
                double[] toTransform = new double[blockSize];

                audioRecord.startRecording();

                // started = true; hopes this should true before calling
                // following while loop

                while (started) {
                    int bufferReadResult = audioRecord.read(buffer, 0,
                            blockSize);

                    for (int i = 0; i < blockSize && i < bufferReadResult; i++) {
                        toTransform[i] = (double) buffer[i] / 32768.0; // signed
                                                                        // 16
                    }                                       // bit
                        transformer.ft(toTransform);
                        publishProgress(toTransform);



                }

                audioRecord.stop();

            } catch (Throwable t) {
                t.printStackTrace();
                Log.e("AudioRecord", "Recording Failed");
            }
            return null;
        }

        @Override
        protected void onProgressUpdate(double[]... toTransform) {

            canvas.drawColor(Color.BLACK);

            for (int i = 0; i < toTransform[0].length; i++) {
                int x = i;
                int downy = (int) (100 - (toTransform[0][i] * 10));
                int upy = 100;

                canvas.drawLine(x, downy, x, upy, paint);
            }

            imageView.invalidate();

            // TODO Auto-generated method stub
            // super.onProgressUpdate(values);
        }

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

    public void onClick(View arg0) {
        // TODO Auto-generated method stub
        if (started) {
            started = false;
            startStopButton.setText("Start");
            recordTask.cancel(true);
        } else {
            started = true;
            startStopButton.setText("Stop");
            recordTask = new RecordAudio();
            recordTask.execute();
        }
    }
}

这篇关于捕获声音进行分析和可视化的频率在Android中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！