有这样一个问题 https://stackoverflow.com/questions/8048692/android-visualizer-fft-waveform-affected-by-device-volume已经,但似乎建议的解决方法根本不起作用。当音量一直调低但 MediaPlayer 仍在播放时,可视化工具的输出仍然受到全局音量的影响并且由零组成。
这是我重现此问题的代码:
player=new MediaPlayer();
player.setAudioSessionId(SHARED_SESSION_ID);
try {
player.setDataSource("https://example.com/song.mp3");
player.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
mp.start();
}
});
player.prepareAsync();
}catch(Exception x){
Log.w(TAG, x);
}
equalizer=new Equalizer(0, SHARED_SESSION_ID);
equalizer.setEnabled(true);
visualizer=new Visualizer(SHARED_SESSION_ID);
int visualizerFftSize=Visualizer.getCaptureSizeRange()[1];
visualizer.setCaptureSize(visualizerFftSize);
visualizer.setDataCaptureListener(new Visualizer.OnDataCaptureListener() {
@Override
public void onWaveFormDataCapture(Visualizer visualizer, byte[] waveform, int samplingRate) {
int max=0, min=255;
for(int i=0;i<waveform.length;i++) {
int w=(int)waveform[i] & 0xFF;
max = Math.max(w, max);
min = Math.min(w, min);
}
Log.i(TAG, "wform "+max+" / "+min);
}
@Override
public void onFftDataCapture(Visualizer visualizer, byte[] fft, int samplingRate) {
int max=0;
for(int i=0;i<fft.length;i++)
max=Math.max((int)fft[i] & 0xFF, max);
Log.i(TAG, "fft max "+max);
}
}, Visualizer.getMaxCaptureRate()/2, true, true);
visualizer.setEnabled(true);
说来也怪,这个例子来自 ApiDemos https://android.googlesource.com/platform/development/+/master/samples/ApiDemos/src/com/example/android/apis/media/AudioFxDemo.java在相同的设备(Nexus 5、Nexus 4 和 Nexus 6P)上运行良好。我试图尽可能接近地复制它。我还尝试在初始化可视化器之前或之后初始化和/或启用均衡器,但这绝对没有改变。