WAV相关:从PCM16 Little Endian数据转WAV文件

数据格式

[0.0, -0.0, -0.0, 0.0, 0.0, 0.0, 5.960464477539063e-08, 5.960464477539063e-08, 1.1920928955078125e-07, 1.7881393432617188e-07, 2.384185791015625e-07,.....]

转换方法:c#

using System;
using System.IO;
using System.Text;
 
namespace deserialfromPCMData
{
 public static class BinaryWriterExtensions
{
   private const int HeaderSize = ;
 
   private const int Hz = ; //frequency or sampling rate
 
   private const float RescaleFactor = ; //to convert float to Int16
 
   public static void AppendWaveData<T>(this T stream, float[] buffer)
      where T : Stream
   {
      if (stream.Length > HeaderSize)
      {
         stream.Seek(, SeekOrigin.End);
      }
      else
      {
         stream.SetLength(HeaderSize);
         stream.Position = HeaderSize;
      }
 
      // rescale
      var floats = Array.ConvertAll(buffer, x => (short)(x * RescaleFactor));
 
      // Copy to bytes
      var result = new byte[floats.Length * sizeof(short)];
      Buffer.BlockCopy(floats, , result, , result.Length);
 
      // write to stream
      stream.Write(result, , result.Length);
 
      // Update Header
      UpdateHeader(stream);
   }
 
   public static void UpdateHeader(Stream stream)
   {
      var writer = new BinaryWriter(stream);
 
      writer.Seek(, SeekOrigin.Begin);
 
      writer.Write(Encoding.ASCII.GetBytes("RIFF")); //RIFF marker. Marks the file as a riff file. Characters are each 1 byte long.
      writer.Write((int)(writer.BaseStream.Length - )); //file-size (equals file-size - 8). Size of the overall file - 8 bytes, in bytes (32-bit integer). Typically, you'd fill this in after creation.
      writer.Write(Encoding.ASCII.GetBytes("WAVE")); //File Type Header. For our purposes, it always equals "WAVE".
      writer.Write(Encoding.ASCII.GetBytes("fmt ")); //Mark the format section. Format chunk marker. Includes trailing null.
      writer.Write(); //Length of format data.  Always 16.
      writer.Write((short)); //Type of format (1 is PCM, other number means compression) . 2 byte integer. Wave type PCM
      writer.Write((short)); //Number of Channels - 2 byte integer
      writer.Write(Hz); //Sample Rate - 32 byte integer. Sample Rate = Number of Samples per second, or Hertz.
      writer.Write(Hz *  * ); // sampleRate * bytesPerSample * number of channels, here 16000*2*1.
      writer.Write((short)( * )); //channels * bytesPerSample, here 1 * 2  // Bytes Per Sample: 1=8 bit Mono,  2 = 8 bit Stereo or 16 bit Mono, 4 = 16 bit Stereo
      writer.Write((short)); //Bits per sample (BitsPerSample * Channels) ?? should be 8???
      writer.Write(Encoding.ASCII.GetBytes("data")); //"data" chunk header. Marks the beginning of the data section.
      writer.Write((int)(writer.BaseStream.Length - HeaderSize)); //Size of the data section. data-size (equals file-size - 44). or NumSamples * NumChannels * bytesPerSample ??
   }
} //end of class
}

using System;
using System.IO;
using System.Text;
 
namespace deserialfromPCMData
{
    class SaveAudioStreamToWav
    {
        static void Main(string[] args)
        {
 
            Stream instream = File.OpenRead(@"g:\sample.txt");
 
            BufferedStream bfs = new BufferedStream(instream);
            byte[] array = new byte[bfs.Length];
            instream.Read(array, , array.Length);
 
            string str = Encoding.Default.GetString(array);
 
            var StreamSample = str.Substring(, str.Length - ).Split(',');
 
            var floatsArray = new float[StreamSample.Length];
            floatsArray = Array.ConvertAll(StreamSample, x => (float)Convert.ToDouble(x));
 
            using (var stream = new FileStream(@"g:\sample2.wav", FileMode.Create, FileAccess.ReadWrite))
            {
               stream.AppendWaveData(floatsArray);
            }
        }
    }
}

Java方法:

package com;
 
import com.sun.media.sound.WaveFileWriter;
import org.junit.Test;
 
import javax.sound.sampled.AudioFileFormat;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import java.io.*;
import java.util.Arrays;
 
//https://stackoverflow.com/questions/3599378/java-read-wav-file-as-a-float-array
//
//https://stackoverflow.com/questions/26824663/how-do-i-use-audio-sample-data-from-java-sound
//
//https://stackoverflow.com/questions/4440015/java-pcm-to-wav
public class TestWavFile {
 
    //采样率16kHz
    private float SAMPLING_RATE = 16000;
    private float sampleSizeBits = 16;
 
    //把short(2字节)拆解成字节流byte[2]
    public byte[] get16BitPcm(short[] data) {
 
        byte[] resultData = new byte[2 * data.length];
        int iter = 0;
        for (short sample : data) {
            resultData[iter++] = (byte)(sample & 0x00ff);
            resultData[iter++] = (byte)((sample & 0xff00) >>> 8);
        }
        return resultData;
    }
 
    @Test
    public void test() throws IOException{
 
        BufferedReader bufferedReader = new BufferedReader(
                new InputStreamReader(
                        new FileInputStream("g:/sample.txt")));
 
        StringBuffer buffer = new StringBuffer();
        String line = null;
 
        while ( (line = bufferedReader.readLine()) != null)
        {
            buffer.append(line);
        }
 
        int len = buffer.length();
 
        String raw = buffer.substring(1,len-1);
 
        Short[] data = Arrays.stream(raw.split(","))
                .map(track->( Float.valueOf(track) * 0x7fff ))
                .map(item->item.shortValue()).toArray(Short[]::new);
 
        short [] frameData = new short[data.length];
 
        for (int i = 0;  i< data.length; i++) {
            frameData[i] = data[i];
        }
 
        WaveFileWriter writer = new WaveFileWriter();
 
        FileOutputStream outStream = new FileOutputStream("g:/sample.wav");
        //(采样率,比特位,通道,是否有符号,大小端)
        //比特位:short 2个字节  2*8 = 16
        //是否有符号:是否有负数
        //
        AudioFormat format = new AudioFormat(SAMPLING_RATE,16,1,true,false);
 
        AudioInputStream audioInputStream = new AudioInputStream(new ByteArrayInputStream(get16BitPcm(frameData)), format, frameData.length);
 
        writer.write(audioInputStream, AudioFileFormat.Type.WAVE, outStream);
 
    }
}

java封装工具：

import com.fasterxml.jackson.databind.ObjectMapper;
import com.sun.media.sound.WaveFileWriter;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.ArrayUtils;
 
import javax.sound.sampled.AudioFileFormat;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import java.io.ByteArrayInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Arrays;
 
@Slf4j
public final class WavFileGenerator {
 
    //采样率16kHz
    private float SAMPLING_RATE = 16000;
    private float sampleSizeBits = 16;
 
    private int HeaderSize = 44;
 
    //frequency or sampling rate
    private int Hz = 16_000;
 
    private byte[] values;
 
    public WavFileGenerator(String ctx)
    {
        this(convert(ctx));
    }
    public WavFileGenerator(String []values)
    {
        convert(toPrimitive(Arrays.asList(values).stream().map(Float::valueOf).toArray(size -> new Float[size])));
    }
 
    public WavFileGenerator(short[] values)
    {
        /*sizeof(short) was 2 bytes in java platform*/
        byte[] result = new byte[values.length * 2];
 
        // 1short = 2bytes
        int iter = 0;
        for (short sample : values) {
            result[iter++] = (byte)(sample & 0x00ff);
            result[iter++] = (byte)((sample & 0xff00) >>> 8);
        }
 
        this.values = result;
    }
    public WavFileGenerator(float[] floatValues)
    {
        this(convert(floatValues));
    }
 
    static float[] toPrimitive(Float[] floats)
    {
        return ArrayUtils.toPrimitive(floats);
    }
 
    public static final short[] convert(float[] values)
    {
        //PCM 16bit little endian
        short[] shortValues = new short[values.length];
        for (int i = 0; i < values.length; i++) {
            float value = values[i];
                shortValues[i] = (short) (value < 0 ? value* 0x8000 : value*0x7fff);
        }
       return shortValues;
    }
 
    public static final float[] convert(String ctx)
    {
        ObjectMapper objectMapper = new ObjectMapper();
        try {
            Float[] data = objectMapper.readValue(ctx, Float[].class);
            return toPrimitive(data);
        } catch (IOException e) {
            log.error("转换出错:{}",e);
        }
        return new float[0];
    }
 
    public byte[] getFmtChunk()
    {
        return null;
    }
 
    public byte[] getDataChunk()
    {
        return values;
    }
 
    void builder()
    {
 
    }
 
    public ByteBuffer getAudioStream()
    {
            return null;
    }
 
    public void saveFile(String dest) throws IOException {
 
        WaveFileWriter writer = new WaveFileWriter();
        FileOutputStream outStream = new FileOutputStream(dest);
        AudioFormat format = new AudioFormat(SAMPLING_RATE,16,1,true,false);
        int frames = values.length / 2;
        AudioInputStream audioInputStream = new AudioInputStream(new ByteArrayInputStream(values), format, frames);
        writer.write(audioInputStream, AudioFileFormat.Type.WAVE, outStream);
        audioInputStream.close();
        outStream.close();
    }
}

运行以上两个文件,最终会成功wav文件。

样本数据