【发布时间】：2014-11-18 07:29:07
【问题描述】：
我想通过修改字节向音频文件 (.wav) 添加过滤器，但我遇到的问题是声音有噪音。
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);
}
}
谁能帮我解决奇怪的声音以及如何获得更多的音频过滤器算法和实现。
【问题讨论】：
标签： android algorithm audio byte