Android 音频滤波算法
我想通过修改字节向音频文件(.wav)添加一个过滤器,但问题是声音有噪声Android 音频滤波算法,android,algorithm,audio,byte,Android,Algorithm,Audio,Byte,我想通过修改字节向音频文件(.wav)添加一个过滤器,但问题是声音有噪声 public class MainActivity extends ActionBarActivity { private int bufferSize = 0; private static final int RECORDER_BPP = 16; private static final String AUDIO_RECORDER_FILE_EXT_WAV = ".wav"; priva
public class MainActivity extends ActionBarActivity {
private int bufferSize = 0;
private static final int RECORDER_BPP = 16;
private static final String AUDIO_RECORDER_FILE_EXT_WAV = ".wav";
private static final String AUDIO_RECORDER_FOLDER = "ks";
private static final int RECORDER_SAMPLERATE = 44100;
private static final int RECORDER_CHANNELS = AudioFormat.CHANNEL_IN_STEREO;
private static final int RECORDER_AUDIO_ENCODING = AudioFormat.ENCODING_PCM_16BIT;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bufferSize = AudioRecord.getMinBufferSize(RECORDER_SAMPLERATE,
RECORDER_CHANNELS, RECORDER_AUDIO_ENCODING);
String file1 = "/storage/emulated/0/File/rec.wav";
String file2 = "/storage/emulated/0/File/rec2.wav";
copyWaveFile(file1,file2);
}
static final float ALPHA = 0.15f;
private float[] lowPass(float[] input, float[] output) {
if (output == null)
return input;
for (int n = 0; n < input.length; n++) {
output[n] = output[n] + ALPHA * (input[n] - output[n]);
}
return output;
}
private static float[] toFloatArray(byte[] buffer) {
ByteArrayInputStream bas = new ByteArrayInputStream(buffer);
DataInputStream ds = new DataInputStream(bas);
float[] fArr = new float[buffer.length / 4]; // 4 bytes per float
for (int i = 0; i < fArr.length; i++) {
try {
fArr[i] = ds.readFloat();
} catch (IOException e) {
Log.e("E", "eRRO :" + e.getMessage());
e.printStackTrace();
}
}
return fArr;
}
private static byte[] toByteArray(float[] fArr) {
ByteArrayOutputStream bas = new ByteArrayOutputStream();
DataOutputStream ds = new DataOutputStream(bas);
for (float f : fArr)
try {
ds.writeFloat(f);
} catch (IOException e) {
Log.i("", "ERROR:" + e.getMessage());
e.printStackTrace();
}
byte[] bytes = bas.toByteArray();
return bytes;
}
private void copyWaveFile(String file1, String file2) {
FileInputStream in1 = null;
FileOutputStream out = null;
long totalAudioLen = 0;
long totalDataLen = totalAudioLen + 36;
long longSampleRate = RECORDER_SAMPLERATE;
int channels = 2;
long byteRate = RECORDER_BPP * RECORDER_SAMPLERATE * channels / 8;
byte[] data = new byte[bufferSize];
byte[] dataOut = new byte[bufferSize];
float[] floatArray = null;
try {
in1 = new FileInputStream(file1);
out = new FileOutputStream(file2);
totalAudioLen = in1.getChannel().size();
totalDataLen = totalAudioLen + 36;
WriteWaveFileHeader(out, totalAudioLen, totalDataLen,
longSampleRate, channels, byteRate);
while (in1.read(data) != -1) {
floatArray = lowPass(toFloatArray(data), toFloatArray(dataOut));
// out.write(data); original
out.write(toByteArray(floatArray));
}
out.close();
in1.close();
Toast.makeText(this, "Done!!", Toast.LENGTH_LONG).show();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
private void WriteWaveFileHeader(FileOutputStream out, long totalAudioLen,
long totalDataLen, long longSampleRate, int channels, long byteRate)
throws IOException {
byte[] header = new byte[44];
header[0] = 'R'; // RIFF/WAVE header
header[1] = 'I';
header[2] = 'F';
header[3] = 'F';
header[4] = (byte) (totalDataLen & 0xff);
header[5] = (byte) ((totalDataLen >> 8) & 0xff);
header[6] = (byte) ((totalDataLen >> 16) & 0xff);
header[7] = (byte) ((totalDataLen >> 24) & 0xff);
header[8] = 'W';
header[9] = 'A';
header[10] = 'V';
header[11] = 'E';
header[12] = 'f'; // 'fmt ' chunk
header[13] = 'm';
header[14] = 't';
header[15] = ' ';
header[16] = 16; // 4 bytes: size of 'fmt ' chunk
header[17] = 0;
header[18] = 0;
header[19] = 0;
header[20] = 1; // format = 1
header[21] = 0;
header[22] = (byte) channels;
header[23] = 0;
header[24] = (byte) (longSampleRate & 0xff);
header[25] = (byte) ((longSampleRate >> 8) & 0xff);
header[26] = (byte) ((longSampleRate >> 16) & 0xff);
header[27] = (byte) ((longSampleRate >> 24) & 0xff);
header[28] = (byte) (byteRate & 0xff);
header[29] = (byte) ((byteRate >> 8) & 0xff);
header[30] = (byte) ((byteRate >> 16) & 0xff);
header[31] = (byte) ((byteRate >> 24) & 0xff);
header[32] = (byte) (2 * 16 / 8); // block align
header[33] = 0;
header[34] = RECORDER_BPP; // bits per sample
header[35] = 0;
header[36] = 'd';
header[37] = 'a';
header[38] = 't';
header[39] = 'a';
header[40] = (byte) (totalAudioLen & 0xff);
header[41] = (byte) ((totalAudioLen >> 8) & 0xff);
header[42] = (byte) ((totalAudioLen >> 16) & 0xff);
header[43] = (byte) ((totalAudioLen >> 24) & 0xff);
out.write(header, 0, 44);
}
}
公共类MainActivity扩展了ActionBarActivity{
私有int bufferSize=0;
专用静态最终整数记录器_BPP=16;
专用静态最终字符串音频\u记录器\u文件\u EXT\u WAV=“.WAV”;
专用静态最终字符串音频\u记录器\u FOLDER=“ks”;
专用静态最终积分记录仪\u采样器=44100;
专用静态最终整数记录器\u通道=立体声中的AudioFormat.CHANNEL\u;
专用静态最终整数记录器\u音频\u编码=AudioFormat.ENCODING\u PCM\u 16位;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bufferSize=AudioRecord.getMinBufferSize(记录器\u采样器,
录像机信道、录像机音频编码);
字符串file1=“/storage/emulated/0/File/rec.wav”;
字符串file2=“/storage/emulated/0/File/rec2.wav”;
copyWaveFile(文件1、文件2);
}
静态最终浮动α=0.15f;
专用浮点[]低通(浮点[]输入,浮点[]输出){
if(输出==null)
返回输入;
对于(int n=0;n>8)和0xff);
头[6]=(字节)((totalDataLen>>16)和0xff);
头[7]=(字节)((totalDataLen>>24)和0xff);
标题[8]=“W”;
标题[9]=“A”;
标题[10]=“V”;
标题[11]=“E”;
标题[12]=“f”;/“fmt”块
标题[13]=“m”;
标题[14]=“t”;
标题[15]='';
header[16]=16;//4字节:“fmt”块的大小
标题[17]=0;
标题[18]=0;
标题[19]=0;
头[20]=1;//格式=1
头[21]=0;
头[22]=(字节)通道;
标题[23]=0;
头文件[24]=(字节)(longSampleRate&0xff);
头[25]=(字节)((长采样>>8)和0xff);
头[26]=(字节)((长采样>>16)和0xff);
头[27]=(字节)((长采样>>24)和0xff);
头[28]=(字节)(字节和0xff);
头[29]=(字节)((字节>>8)和0xff);
头[30]=(字节)((字节>>16)和0xff);
头[31]=(字节)((字节>>24)和0xff);
头[32]=(字节)(2*16/8);//块对齐
标题[33]=0;
头[34]=记录器\u BPP;//每个样本的位
标题[35]=0;
标题[36]=“d”;
标题[37]=“a”;
标题[38]=“t”;
标题[39]=“a”;
标题[40]=(字节)(totalAudioLen&0xff);
头[41]=(字节)((totalAudioLen>>8)和0xff);
头[42]=(字节)((totalAudioLen>>16)和0xff);
头[43]=(字节)((totalAudioLen>>24)和0xff);
out.write(头,0,44);
}
}
有人可以帮助我处理奇怪的声音,以及如何获得更多的音频滤波器算法和实现。您可以尝试使用Matlab查看波形类型和频率类型