Android 将字节写入wav文件会增加背景噪音

Android 将字节写入wav文件会增加背景噪音,android,audio,bytearray,Android,Audio,Bytearray,我正在从wav文件读取值;仅选择其中一些值并将其写入另一个wav文件(以便从wav文件中删除静默期)。问题是,当我创建这个新的wav文件时,它有背景噪声(在原始wav文件中不存在)。我在这里添加了代码的一部分,该部分用于编写文件: private void writeToFile(String filePath) { short nChannels = 1; int sRate = 16000; short bSamples = 16;

我正在从wav文件读取值;仅选择其中一些值并将其写入另一个wav文件(以便从wav文件中删除静默期)。问题是,当我创建这个新的wav文件时,它有背景噪声(在原始wav文件中不存在)。我在这里添加了代码的一部分,该部分用于编写文件:

private void writeToFile(String filePath) {
        short nChannels = 1;
        int sRate = 16000;
        short bSamples = 16;
        audioShorts = new short[size];
        int nSamples = 0;
        for(int i=0; i<size-1; i++) {
            //audioShorts[i] = Short.reverseBytes((short)(zff[i]*0x8000));
            if(slope[i] >= slopeThreshold) { // Voice region -- Should be written to output
                audioShorts[nSamples] = Short.reverseBytes((short)(a[i]*0x8000));
                audioShorts[nSamples+1] = Short.reverseBytes((short)(a[i+1]*0x8000));
                nSamples += 2;
                i++;
            }
            /*else
                audioShorts[i] = 0;*/
        }
        finalShorts = new short[nSamples];
        for(int i=0; i<nSamples; i++){
            finalShorts[i] = audioShorts[i];
        }
        data = new byte[finalShorts.length*2];
        ByteBuffer buffer = ByteBuffer.wrap(data);
        ShortBuffer sbuf =  buffer.asShortBuffer();
        sbuf.put(finalShorts);
        data = buffer.array();
        Log.d("Data length------------------------------", Integer.toString(data.length));
        RandomAccessFile randomAccessWriter;
        try {
            randomAccessWriter = new RandomAccessFile(filePath, "rw");
            randomAccessWriter.setLength(0); // Set file length to 0, to prevent unexpected behaviour in case the file already existed
            randomAccessWriter.writeBytes("RIFF");
            randomAccessWriter.writeInt(Integer.reverseBytes(36+data.length)); // File length 
            randomAccessWriter.writeBytes("WAVE");
            randomAccessWriter.writeBytes("fmt ");
            randomAccessWriter.writeInt(Integer.reverseBytes(16)); // Sub-chunk size, 16 for PCM
            randomAccessWriter.writeShort(Short.reverseBytes((short) 1)); // AudioFormat, 1 for PCM
            randomAccessWriter.writeShort(Short.reverseBytes(nChannels));// Number of channels, 1 for mono, 2 for stereo
            randomAccessWriter.writeInt(Integer.reverseBytes(sRate)); // Sample rate
            randomAccessWriter.writeInt(Integer.reverseBytes(sRate*bSamples*nChannels/8)); // Byte rate, SampleRate*NumberOfChannels*BitsPerSample/8
            randomAccessWriter.writeShort(Short.reverseBytes((short)(nChannels*bSamples/8))); // Block align, NumberOfChannels*BitsPerSample/8
            randomAccessWriter.writeShort(Short.reverseBytes(bSamples)); // Bits per sample
            randomAccessWriter.writeBytes("data");
            randomAccessWriter.writeInt(Integer.reverseBytes(data.length)); // No. of samples
            randomAccessWriter.write(data);
            randomAccessWriter.close();

        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
private void writeToFile(字符串文件路径){
短n通道=1;
int sRate=16000;
短b样本=16;
audioShorts=新短款[尺寸];
int nSamples=0;
对于(int i=0;i=slopeThreshold){//Voice region--应写入输出
音频短路[nSamples]=短反向字节((短)(a[i]*0x8000));
音频短路[nSamples+1]=短反向字节((短)(a[i+1]*0x8000));
nSamples+=2;
i++;
}
/*否则
音频短片[i]=0*/
}
finalShorts=新的短[nSamples];

对于(inti=0;i您的代码片段遗漏了一些细节(比如slope和slopeThreshold是什么),因此将此答案视为一个建议

一般来说,这种音频数据的截断会引入噪声。这取决于剪切发生的位置。如果剪切前的最后一个采样与剪切后的第一个采样相同,则是安全的,否则会引入咔嗒声

如果切割不频繁,你会听到个别的咔嗒声,但如果切割次数足够频繁,听起来可能像连续的噪音

要做到这一点而不点击,你需要添加一个简短的淡出和淡入周围的每个削减

编辑:尝试删除“if(slope[i]>=slopeThreshold)”条件,看看噪声是否消失。如果消失,噪声很可能是我所描述的结果。否则,您可能会在各种字节转换中出错。

而不是:

   data = new byte[finalShorts.length*2];
    ByteBuffer buffer = ByteBuffer.wrap(data);
    ShortBuffer sbuf =  buffer.asShortBuffer();
    sbuf.put(finalShorts);
    data = buffer.array();
是否有必要将短[]转换为字节[]

data = shortToBytes(finalShorts);

public byte [] shortToBytes(short [] input){
  int short_index, byte_index;
  int iterations = input.length;

  byte [] buffer = new byte[input.length * 2];

  short_index = byte_index = 0;

  for(/*NOP*/; short_index != iterations; /*NOP*/)
  {
    buffer[byte_index]     = (byte) (input[short_index] & 0x00FF); 
    buffer[byte_index + 1] = (byte) ((input[short_index] & 0xFF00) >> 8);

    ++short_index; byte_index += 2;
  }

  return buffer;
}

这对我有用。

你是否应用了过滤器来去除背景噪音?因为麦克风不会过滤掉背景噪音,所以你必须通过编程来进行过滤。原始录制的wav文件(从中获取值)没有噪音。噪音会添加到我正在创建的新wav文件中。