Android Visualizer 实现崩溃

Question

我正在尝试实现 Android Visualizer 类。我已经查找了其他问题线程，但仍然遇到致命错误。在我看来，这一切都应该正常工作，无论出于何种原因 AVD 不断崩溃。

首先，我使用权限：

<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/>

这是我的 logcat：

12-21 15:10:46.983: D/dalvikvm(642): Not late-enabling CheckJNI (already on)
12-21 15:10:48.823: D/MediaPlayer(642): Couldn't open file on client side, trying server     side  
12-21 15:10:53.603: E/AudioEffect(642): set(): AudioFlinger could not create effect,    status: -22
12-21 15:10:53.603: E/visualizers-JNI(642): Visualizer initCheck failed -4
12-21 15:10:53.613: E/Visualizer-JAVA(642): Error code -4 when initializing Visualizer.
12-21 15:10:53.613: E/Visual Ex(642): Cannot initialize Visualizer engine, error: -4
12-21 15:10:53.964: D/gralloc_goldfish(642): Emulator without GPU emulation detected.

和我的代码：

package MediaPlayer.namespace;

import java.io.IOException;

import android.app.Activity;
import android.media.MediaPlayer;
import android.media.MediaRecorder;
import android.media.audiofx.Visualizer;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;

public class MediaPlayerActivity extends Activity 
{
Visualizer      visual;
int             formattedVizData[];
byte            rawWaveForm[];
int             cont = 0xFF;

public void onCreate(Bundle savedInstanceState) 
{
    //start
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    ///start media player & visualizer.
    MediaPlayer mediaPlayer = new MediaPlayer();
    mediaPlayer = MediaPlayer.create(this, Uri.parse("http://vprbbc.streamguys.net:80/vprbbc24.mp3"));
    mediaPlayer.start();
    // Create the Visualizer object and attach it to our media player.
    try{
        visual = new Visualizer(mediaPlayer.getAudioSessionId()); // this line causing Exception 
        visual.setEnabled(true);
        visual.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
        }
        catch(Exception ex)
        {
            Log.e("Visual Ex", ex.getMessage());
        }
    }
}

Answer 1

我有同样的问题，所以尝试添加

AndroidManifest.xml 文件中的权限

另外，如果您不想看到奥迪波形，您应该在画布或其他东西中显示它...

工作示例：

//android.permission.MODIFY_AUDIO_SETTINGS for audio settings and also
//android.permission.INTERNET for internet streaming

package com.janilemy;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.audiofx.Visualizer;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.SeekBar;
import android.widget.TextView;

import java.io.IOException;

public class AudioFxDemoActivity extends Activity {

    //Here is your URL defined
String url = "http://vprbbc.streamguys.net/vprbbc24.mp3";

    //Constants for vizualizator - HEIGHT 50dip
private static final float VISUALIZER_HEIGHT_DIP = 50f;

    //Your MediaPlayer
MediaPlayer mp;

//Vizualization
private Visualizer mVisualizer;

    private LinearLayout mLinearLayout;
    private VisualizerView mVisualizerView;
    private TextView mStatusTextView;


/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    //Info textView
    mStatusTextView = new TextView(this);

    //Create new LinearLayout ( because main.xml is empty )
    mLinearLayout = new LinearLayout(this);
    mLinearLayout.setOrientation(LinearLayout.VERTICAL);
    mLinearLayout.addView(mStatusTextView);

    //set content view to new Layout that we create
    setContentView(mLinearLayout);

    //start media player - like normal
    mp = new MediaPlayer();
    mp.setAudioStreamType(AudioManager.STREAM_MUSIC);

    try {
        mp.setDataSource(url); // set data source our URL defined
    } catch (IllegalArgumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IllegalStateException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }       

    try {   //tell your player to go to prepare state
        mp.prepare(); 
    } catch (IllegalStateException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
            //Start your stream / player
    mp.start();

    //setup your Vizualizer - call method
    setupVisualizerFxAndUI();        

            //enable vizualizer
            mVisualizer.setEnabled(true);

            //Info text
    mStatusTextView.setText("Playing audio...");
}

    //Our method that sets Vizualizer
private void setupVisualizerFxAndUI() {
    // Create a VisualizerView (defined below), which will render the simplified audio
    // wave form to a Canvas.

    //You need to have something where to show Audio WAVE - in this case Canvas
    mVisualizerView = new VisualizerView(this);
    mVisualizerView.setLayoutParams(new ViewGroup.LayoutParams(
            ViewGroup.LayoutParams.FILL_PARENT,
            (int)(VISUALIZER_HEIGHT_DIP * getResources().getDisplayMetrics().density)));
    mLinearLayout.addView(mVisualizerView);

    // Create the Visualizer object and attach it to our media player.
    //YOU NEED android.permission.RECORD_AUDIO for that in AndroidManifest.xml
    mVisualizer = new Visualizer(mp.getAudioSessionId());
    mVisualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
    mVisualizer.setDataCaptureListener(new Visualizer.OnDataCaptureListener() {
        public void onWaveFormDataCapture(Visualizer visualizer, byte[] bytes,
                int samplingRate) {
            mVisualizerView.updateVisualizer(bytes);
        }

        public void onFftDataCapture(Visualizer visualizer, byte[] bytes, int samplingRate) {}
    }, Visualizer.getMaxCaptureRate() / 2, true, false); 
}

@Override
protected void onPause() {
    super.onPause();

    if (isFinishing() && mp != null) {
        mVisualizer.release();
        mEqualizer.release();
        mp.release();
        mp = null;
    }
}

/**
 * A simple class that draws waveform data received from a
 * {@link Visualizer.OnDataCaptureListener#onWaveFormDataCapture }
 */
class VisualizerView extends View {
    private byte[] mBytes;
    private float[] mPoints;
    private Rect mRect = new Rect();

    private Paint mForePaint = new Paint();

    public VisualizerView(Context context) {
        super(context);
        init();
    }

    private void init() {
        mBytes = null;

        mForePaint.setStrokeWidth(1f);
        mForePaint.setAntiAlias(true);
        mForePaint.setColor(Color.rgb(0, 128, 255));
    }

    public void updateVisualizer(byte[] bytes) {
        mBytes = bytes;
        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (mBytes == null) {
            return;
        }

        if (mPoints == null || mPoints.length < mBytes.length * 4) {
            mPoints = new float[mBytes.length * 4];
        }

        mRect.set(0, 0, getWidth(), getHeight());

        for (int i = 0; i < mBytes.length - 1; i++) {
            mPoints[i * 4] = mRect.width() * i / (mBytes.length - 1);
            mPoints[i * 4 + 1] = mRect.height() / 2
                    + ((byte) (mBytes[i] + 128)) * (mRect.height() / 2) / 128;
            mPoints[i * 4 + 2] = mRect.width() * (i + 1) / (mBytes.length - 1);
            mPoints[i * 4 + 3] = mRect.height() / 2
                    + ((byte) (mBytes[i + 1] + 128)) * (mRect.height() / 2) / 128;
        }

        canvas.drawLines(mPoints, mForePaint);
    }
}

}

这是 Android 媒体播放器音频波形可视化的完整工作示例...我希望它能帮助您解决问题...

Jani L

Answer 2

使用 Visualizer 有一些重要的事情。

1. 最低api级别必须等于或大于9。
2. Visualizer引擎，错误：-1表示RECORD_AUDIO权限是
   丢失的。
3. Visualizer 引擎，错误：-4 表示由于参数错误而操作失败。价值。展示台的配置有问题，您没有正确设置展示台。

另请参阅我的此处的答案。

注意

参数 (audioSession) 系统范围内唯一的音频会话标识符。如果audioSession不为0，则可视化器将附加到同一音频会话中的MediaPlayer或AudioTrack。否则，Visualizer 将应用于输出混合。

Answer 3

@Kaushal28、@ihsan、gaozp、@Big Money

-3 错误代码表示 ERROR_NO_INIT
注意： https://developer.android.com/reference/kotlin/ android/media/audiofx/Visualizer

我有同样的经历并使用了AudioRecorder的audioSessionId。

如果你检查Visualizer的文档，你只能使用MediaPlayer和AudioTrack，如下所示。

If audioSession is not 0, the visualizer will be attached to the 
MediaPlayer or AudioTrack in the same audio session. Otherwise, 
the Visualizer will apply to the output mix.

Answer 4

您缺少互联网权限

<uses-permission android:name="android.permission.INTERNET" />

Answer 5

启用 Visulizer 后，您无法对它的对象进行任何更改。因此，只需交换到如亲爱的代码所示的行即可。

public class MediaPlayerActivity extends Activity {

    Visualizer visual;
    int formattedVizData[];
    byte rawWaveForm[];
    int cont = 0xFF;

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        // Start media player & visualizer.
        MediaPlayer mediaPlayer = new MediaPlayer();
        mediaPlayer = MediaPlayer.create(this, Uri.parse("http://vprbbc.streamguys.net:80/vprbbc24.mp3"));
        mediaPlayer.start();

        // Create the Visualizer object and attach it to our media player.
        try {

            // this line is not actually causing Exception ,It is because u are
            // enabling the visulizer to capture data & and after that setting
            // the capture size of buffer. U can't make any changes after
            // enabling it. I tried this same code and it's working fine for me
            visual = new Visualizer(mediaPlayer.getAudioSessionId());

            visual.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
            visual.setEnabled(true);
        } 
        catch (Exception ex) {
            Log.e("Visual Ex", ex.getMessage());
        }

    }

}

请参阅此链接以获得最佳示例https://github.com/felixpalmer/android-visualizer

Answer 6

完成所有操作后，如果可视化未启动，请尝试 Visualizationview.startRendering()