文章目录
- 前言
- 一、如何实现？
- 1.定义头结构
- 2.预留头部空间
- 3.写入PCM数据
- 4.写入头部信息
- 二、完整代码
- 三、使用示例
- 总结
前言
之前实现了《C++ 将音频PCM数据封装成wav文件》，最近将其改成了C#版本。使用C#实现录音功能时还是需要写wav文件的，直接用C#实现也是比较简单的，这样可以免去不必要的依赖。
一、如何实现？
首先需要构造wav头部，wav文件音频信息全部保存在头部，我们要做的就是在PCM数据的前面加入wav头，并且记录PCM的相关参数。
1.定义头结构
只定义PCM格式的wav文件头，包含3部分riff、format、data。需要使用[StructLayout(LayoutKind.Sequential)]描述结构体，确保内存连续。
WAV头部
//WAV头部结构-PCM格式
[StructLayout(LayoutKind.Sequential)]
struct WavPCMFileHeader
{RIFF riff=new RIFF();Format format = new Format();Data data = new Data();public WavPCMFileHeader() { }
}
RTTF部分
[StructLayout(LayoutKind.Sequential)]
struct RIFF
{byte r = (byte)'R';byte i = (byte)'I';byte f = (byte)'F';byte t = (byte)'F';public uint fileLength = 0;byte w = (byte)'W';byte a = (byte)'A';byte v = (byte)'V';byte e = (byte)'E';public RIFF() { }
}
Format部分
[StructLayout(LayoutKind.Sequential)]
struct Format
{byte f = (byte)'f';byte m = (byte)'m';byte t = (byte)'t';byte s = (byte)' ';public uint blockSize = 16;public ushort formatTag=0;public ushort channels = 0;public uint samplesPerSec = 0;public uint avgBytesPerSec = 0;public ushort blockAlign = 0;public ushort bitsPerSample = 0;public Format() { }
}
Data部分
[StructLayout(LayoutKind.Sequential)]
struct Data
{byte d = (byte)'d';byte a = (byte)'a';byte t = (byte)'t';byte a2 = (byte)'a';public uint dataLength=0;public Data() { }
}
2.预留头部空间
创建文件时预留头部空间
_stream = File.Open(fileName, FileMode.Create);
_stream!.Seek(Marshal.SizeOf<WavPCMFileHeader>(), SeekOrigin.Begin);
3.写入PCM数据
写入数据
_stream!.Write(data);
4.写入头部信息
关闭文件时，回到起始位置写入头部信息
//写入头部信息
_stream!.Seek(0, SeekOrigin.Begin);
WavPCMFileHeader h = new WavPCMFileHeader(_channels, _sampleRate, _bitsPerSample, (uint)(_stream.Length - Marshal.SizeOf<WavPCMFileHeader>()));
_stream!.Write(StructToBytes(h));
_stream!.Close();
_stream = null;
二、完整代码
.net6.0
WavWriter.cs
using System.Runtime.InteropServices;
/************************************************************************
* @Project: AC::WavWriter
* @Decription: wav文件写入工具
* @Verision: v1.0.0.0
* @Author: Xin Nie
* @Create: 2023/10/8 09:27:00
* @LastUpdate: 2023/10/8 18:28:00
************************************************************************
* Copyright @ 2025. All rights reserved.
************************************************************************/
namespace AC
{ /// <summary>/// wav写入工具，目前只支持pcm格式/// </summary>public class WavWriter:IDisposable{ushort _channels;uint _sampleRate;ushort _bitsPerSample;FileStream? _stream;/// <summary>/// 创建对象/// </summary>/// <param name="fileName">文件名</param>/// <param name="channels">声道数</param>/// <param name="sampleRate">采样率，单位hz</param>/// <param name="bitsPerSample">位深</param>public static WavWriter Create(string fileName, ushort channels, uint sampleRate, ushort bitsPerSample){return new WavWriter(fileName, channels, sampleRate, bitsPerSample); }/// <summary>/// 构造方法/// </summary>/// <param name="fileName">文件名</param>/// <param name="channels">声道数</param>/// <param name="sampleRate">采样率，单位hz</param>/// <param name="bitsPerSample">位深</param>WavWriter(string fileName, ushort channels, uint sampleRate, ushort bitsPerSample){_stream = File.Open(fileName, FileMode.Create);_channels = channels;_sampleRate = sampleRate;_bitsPerSample = bitsPerSample;_stream!.Seek(Marshal.SizeOf<WavPCMFileHeader>(), SeekOrigin.Begin);}/// <summary>/// 写入PCM数据/// </summary>/// <param name="data">PCM数据</param>public void Write(byte[] data){_stream!.Write(data);}/// <summary>/// 写入PCM数据/// </summary>/// <param name="stream">PCM数据</param>public void Write(Stream stream){stream.CopyTo(_stream!);}/// <summary>/// 关闭文件/// </summary>public void Close(){//写入头部信息_stream!.Seek(0, SeekOrigin.Begin);WavPCMFileHeader h = new WavPCMFileHeader(_channels, _sampleRate, _bitsPerSample, (uint)(_stream.Length - Marshal.SizeOf<WavPCMFileHeader>()));_stream!.Write(StructToBytes(h));_stream!.Close();_stream = null;}public void Dispose(){Close();}static byte[] StructToBytes<T>(T obj){int size = Marshal.SizeOf(typeof(T));IntPtr bufferPtr = Marshal.AllocHGlobal(size);try{Marshal.StructureToPtr(obj!, bufferPtr, false);byte[] bytes = new byte[size];Marshal.Copy(bufferPtr, bytes, 0, size);return bytes;}catch (Exception ex){throw new Exception("Error in StructToBytes ! " + ex.Message);}finally{Marshal.FreeHGlobal(bufferPtr);}} }//WAV头部结构-PCM格式[StructLayout(LayoutKind.Sequential)]struct WavPCMFileHeader{[StructLayout(LayoutKind.Sequential)]struct RIFF{byte r = (byte)'R';byte i = (byte)'I';byte f = (byte)'F';byte t = (byte)'F';public uint fileLength = 0;byte w = (byte)'W';byte a = (byte)'A';byte v = (byte)'V';byte e = (byte)'E';public RIFF() { }}[StructLayout(LayoutKind.Sequential)]struct Format{byte f = (byte)'f';byte m = (byte)'m';byte t = (byte)'t';byte s = (byte)' ';public uint blockSize = 16;public ushort formatTag=0;public ushort channels = 0;public uint samplesPerSec = 0;public uint avgBytesPerSec = 0;public ushort blockAlign = 0;public ushort bitsPerSample = 0;public Format() { }}[StructLayout(LayoutKind.Sequential)]struct Data{byte d = (byte)'d';byte a = (byte)'a';byte t = (byte)'t';byte a2 = (byte)'a';public uint dataLength=0;public Data() { }}RIFF riff=new RIFF();Format format = new Format();Data data = new Data();public WavPCMFileHeader() { }public WavPCMFileHeader(ushort nCh, uint nSampleRate, ushort bitsPerSample, uint dataSize){riff.fileLength = (uint)(36 + dataSize);format.formatTag = 1;format.channels = nCh;format.samplesPerSec = nSampleRate;format.avgBytesPerSec = nSampleRate * nCh * bitsPerSample / 8;format.blockAlign = (ushort)(nCh * bitsPerSample / 8);format.bitsPerSample = bitsPerSample;data.dataLength = dataSize;}};
}
三、使用示例
using AC;
try
{using (var ww = WavWriter.Create("test.wav", 2, 44100, 16)){byte[]data;//获取PCM数据//略//获取PCM数据-end//写入PCM数据ww.Write(data);}
}
catch (Exception e)
{Console.WriteLine(e.Message);
}
总结
以上就是今天要讲的内容，PCM封装成wav还是相对较简单的，只要了解wav头结构,然后自定义其头结构，然后再进行一定的测试，就可以实现这样一个功能。
是什么？)
