Android 音频均衡器,可通过拖动调节音频EQ
2011-01-09 12:03 Terry_龙 阅读(7941) 评论(8) 编辑 收藏 举报2.3之后,Google 为Mediaplayer 类添加了EQ支持,如果你需要使用这个EQ功能,有两点需要注意,分别为如下:
- 在配置文件中设置最小的SDK版本为9
- 添加权限android.permission.RECORD_AUDIO 即可使用,具体的使用方法,下文会介绍
为了使应用程序能够支持波段变化,我们需要重新定义一个VIEW对象,在onDraw 方法画频谱,代码如下:
class VisualizerView extends View {
private byte[] mBytes;
private float[] mPoints;
// 矩形区域
private Rect mRect = new Rect();
// 画笔
private Paint mPaint = new Paint();
// 初始化画笔
private void init() {
mBytes = null;
mPaint.setStrokeWidth(1f);
mPaint.setAntiAlias(true);
mPaint.setColor(Color.BLUE);
}
public VisualizerView(Context context) {
super(context);
init();
}
public void updateVisualizer(byte[] mbyte) {
mBytes = mbyte;
invalidate();
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
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, mPaint);
}
}
private byte[] mBytes;
private float[] mPoints;
// 矩形区域
private Rect mRect = new Rect();
// 画笔
private Paint mPaint = new Paint();
// 初始化画笔
private void init() {
mBytes = null;
mPaint.setStrokeWidth(1f);
mPaint.setAntiAlias(true);
mPaint.setColor(Color.BLUE);
}
public VisualizerView(Context context) {
super(context);
init();
}
public void updateVisualizer(byte[] mbyte) {
mBytes = mbyte;
invalidate();
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
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, mPaint);
}
}
另外,为了使用EQ和频谱可视化,我们必须了解以下两个类:
- Visualizer
此类能使应用程序获取当前有效的一部分音频可视化的目的。使用此类必须添加上面提到的权限。 - Equalizer
一个均衡器的类,使用此类可以轻松的操纵音频的频段,和输出的混合 。
具体使用代码和注释见下面:
/**
* 通过mMediaPlayer返回的AudioSessionId创建一个优先级为0均衡器对象 并且通过频谱生成相应的UI和对应的事件
*/
private void setupEqualizeFxAndUi() {
mEqualizer = new Equalizer(0, mMediaPlayer.getAudioSessionId());
mEqualizer.setEnabled(true);// 启用均衡器
TextView eqTextView = new TextView(this);
eqTextView.setText("均衡器:");
mLayout.addView(eqTextView);
// 通过均衡器得到其支持的频谱引擎
short bands = mEqualizer.getNumberOfBands();
// getBandLevelRange 是一个数组,返回一组频谱等级数组,
// 第一个下标为最低的限度范围
// 第二个下标为最大的上限,依次取出
final short minEqualizer = mEqualizer.getBandLevelRange()[0];
final short maxEqualizer = mEqualizer.getBandLevelRange()[1];
for (short i = 0; i < bands; i++) {
final short band = i;
TextView freqTextView = new TextView(this);
freqTextView.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
freqTextView.setGravity(Gravity.CENTER_HORIZONTAL);
// 取出中心频率
freqTextView
.setText((mEqualizer.getCenterFreq(band) / 1000) + "HZ");
mLayout.addView(freqTextView);
LinearLayout row = new LinearLayout(this);
row.setOrientation(LinearLayout.HORIZONTAL);
TextView minDbTextView = new TextView(this);
minDbTextView.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
minDbTextView.setText((minEqualizer / 100) + " dB");
TextView maxDbTextView = new TextView(this);
maxDbTextView.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
maxDbTextView.setText((maxEqualizer / 100) + " dB");
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
layoutParams.weight = 1;
SeekBar seekbar = new SeekBar(this);
seekbar.setLayoutParams(layoutParams);
seekbar.setMax(maxEqualizer - minEqualizer);
seekbar.setProgress(mEqualizer.getBandLevel(band));
seekbar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
// TODO Auto-generated method stub
mEqualizer.setBandLevel(band,
(short) (progress + minEqualizer));
}
});
row.addView(minDbTextView);
row.addView(seekbar);
row.addView(maxDbTextView);
mLayout.addView(row);
}
}
* 通过mMediaPlayer返回的AudioSessionId创建一个优先级为0均衡器对象 并且通过频谱生成相应的UI和对应的事件
*/
private void setupEqualizeFxAndUi() {
mEqualizer = new Equalizer(0, mMediaPlayer.getAudioSessionId());
mEqualizer.setEnabled(true);// 启用均衡器
TextView eqTextView = new TextView(this);
eqTextView.setText("均衡器:");
mLayout.addView(eqTextView);
// 通过均衡器得到其支持的频谱引擎
short bands = mEqualizer.getNumberOfBands();
// getBandLevelRange 是一个数组,返回一组频谱等级数组,
// 第一个下标为最低的限度范围
// 第二个下标为最大的上限,依次取出
final short minEqualizer = mEqualizer.getBandLevelRange()[0];
final short maxEqualizer = mEqualizer.getBandLevelRange()[1];
for (short i = 0; i < bands; i++) {
final short band = i;
TextView freqTextView = new TextView(this);
freqTextView.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
freqTextView.setGravity(Gravity.CENTER_HORIZONTAL);
// 取出中心频率
freqTextView
.setText((mEqualizer.getCenterFreq(band) / 1000) + "HZ");
mLayout.addView(freqTextView);
LinearLayout row = new LinearLayout(this);
row.setOrientation(LinearLayout.HORIZONTAL);
TextView minDbTextView = new TextView(this);
minDbTextView.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
minDbTextView.setText((minEqualizer / 100) + " dB");
TextView maxDbTextView = new TextView(this);
maxDbTextView.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
maxDbTextView.setText((maxEqualizer / 100) + " dB");
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
layoutParams.weight = 1;
SeekBar seekbar = new SeekBar(this);
seekbar.setLayoutParams(layoutParams);
seekbar.setMax(maxEqualizer - minEqualizer);
seekbar.setProgress(mEqualizer.getBandLevel(band));
seekbar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
// TODO Auto-generated method stub
mEqualizer.setBandLevel(band,
(short) (progress + minEqualizer));
}
});
row.addView(minDbTextView);
row.addView(seekbar);
row.addView(maxDbTextView);
mLayout.addView(row);
}
}
/**
* 生成一个VisualizerView对象,使音频频谱的波段能够反映到 VisualizerView上
*/
private void setupVisualizerFxAndUi() {
mVisualizerView = new VisualizerView(this);
mVisualizerView.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
(int) (VISUALIZER_HEIGHT_DIP * getResources()
.getDisplayMetrics().density)));
mLayout.addView(mVisualizerView);
mVisualizer = new Visualizer(mMediaPlayer.getAudioSessionId());
// 参数内必须是2的位数
mVisualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
// 设置允许波形表示,并且捕获它
mVisualizer.setDataCaptureListener(new OnDataCaptureListener() {
@Override
public void onWaveFormDataCapture(Visualizer visualizer,
byte[] waveform, int samplingRate) {
// TODO Auto-generated method stub
mVisualizerView.updateVisualizer(waveform);
}
@Override
public void onFftDataCapture(Visualizer visualizer, byte[] fft,
int samplingRate) {
// TODO Auto-generated method stub
}
}, Visualizer.getMaxCaptureRate() / 2, true, false);
}
* 生成一个VisualizerView对象,使音频频谱的波段能够反映到 VisualizerView上
*/
private void setupVisualizerFxAndUi() {
mVisualizerView = new VisualizerView(this);
mVisualizerView.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
(int) (VISUALIZER_HEIGHT_DIP * getResources()
.getDisplayMetrics().density)));
mLayout.addView(mVisualizerView);
mVisualizer = new Visualizer(mMediaPlayer.getAudioSessionId());
// 参数内必须是2的位数
mVisualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
// 设置允许波形表示,并且捕获它
mVisualizer.setDataCaptureListener(new OnDataCaptureListener() {
@Override
public void onWaveFormDataCapture(Visualizer visualizer,
byte[] waveform, int samplingRate) {
// TODO Auto-generated method stub
mVisualizerView.updateVisualizer(waveform);
}
@Override
public void onFftDataCapture(Visualizer visualizer, byte[] fft,
int samplingRate) {
// TODO Auto-generated method stub
}
}, Visualizer.getMaxCaptureRate() / 2, true, false);
}
进入程序后,在程序入口加载如下代码:
mStatusTextView = new TextView(this);
mLayout = new LinearLayout(this);
mLayout.setOrientation(LinearLayout.VERTICAL);
mLayout.addView(mStatusTextView);
setContentView(mLayout);
mMediaPlayer = MediaPlayer.create(this, R.raw.eason);
setupVisualizerFxAndUi();
setupEqualizeFxAndUi();
mVisualizer.setEnabled(true);
mMediaPlayer.setOnCompletionListener(new OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
// TODO Auto-generated method stub
mVisualizer.setEnabled(false);
}
});
mMediaPlayer.start();
mStatusTextView.setText("播放中。。。");
mLayout = new LinearLayout(this);
mLayout.setOrientation(LinearLayout.VERTICAL);
mLayout.addView(mStatusTextView);
setContentView(mLayout);
mMediaPlayer = MediaPlayer.create(this, R.raw.eason);
setupVisualizerFxAndUi();
setupEqualizeFxAndUi();
mVisualizer.setEnabled(true);
mMediaPlayer.setOnCompletionListener(new OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
// TODO Auto-generated method stub
mVisualizer.setEnabled(false);
}
});
mMediaPlayer.start();
mStatusTextView.setText("播放中。。。");
完整运行效果:
试试改变一下拖动条,听一下音频有什么变化。
源码下载:
注:源码内没有包含音频文件,测试的话自行添加一个MP3文件即可。