C＃创建24位/ 32位的声音wav文件

Question

我下面的微软开发者博客本教程：https://blogs.msdn.microsoft.com/dawate/2009/06/24/intro-to-audio-programming-part-3-synthesizing-simple-wave-audio-using-c/

本教程被称为“简介音频节目”，我执行了所有步骤，但也许我错过了什么。

这是从WaveFormatChunk类在他的谐音法提取的结构件：

    sChunkID = "fmt ";
    dwChunkSize = 16;
    wFormatTag = 1;
    wChannels = 2;
    dwSamplesPerSec = 44100;
    wBitsPerSample = 16;
    wBlockAlign = (ushort)(wChannels * (wBitsPerSample / 8));
    dwAvgBytesPerSec = dwSamplesPerSec * wBlockAlign;

该wBitsPerSample设置生成的函数的位深，很简单至今。

然后，运行程序，所有与此环境中工作。产生1Hz的频率与在16位幅度32760 /这44.1ksample是结果：

1Hz 16bit 44.1k

这显然是一个正确的输出。

现在我引用它：

我们使用短裤的阵列，因为我们有16位样本作为格式块中指定。如果要更改为8位音频，使用一个字节数组。如果您想使用32位音频，使用float数组。

谈shortArray类WaveDataChunk

public class WaveDataChunk
{
    public string sChunkID;     // "data"
    public uint dwChunkSize;    // Length of header in bytes
    public short[] shortArray;

然后，32位音频，改变shortArray浮动：

public float[] shortArray;

和wBitsPerSample至32：

wBitsPerSample = 32;

这是结果：1Hz 32bit 44.1k

实际上，频率加倍，只有一半的时间被写入。我做错了什么？？我已经做什么？

Answer 1

当您使用IEEE浮点，范围应该是-1..1（而不是最小..最大整数）。此外，格式于是不再MS PCM（1），但IEEE FLOAT（3）。

与文章的问题是，它的块定义，不考虑IEEE浮点格式初始化。这里是我的建议，以使代码更通用（直译）;组块将初始化（我造只读）在构造根据所选择的类型的字段：

public class WaveFormatChunk<T> where T: struct, IConvertible
{
    public readonly string sChunkID;         // Four bytes: "fmt "
    public readonly uint dwChunkSize;        // Length of chunk in bytes
    public readonly ushort wFormatTag;       // 1 (MS PCM)
    public readonly ushort wChannels;        // Number of channels
    public readonly uint dwSamplesPerSec;    // Frequency of the audio in Hz... 44100
    public readonly uint dwAvgBytesPerSec;   // for estimating RAM allocation
    public readonly ushort wBlockAlign;      // sample frame size, in bytes
    public readonly ushort wBitsPerSample;    // bits per sample

    /// <summary>
    /// Initializes a format chunk. Supported data types: byte, short, float
    /// </summary>
    public WaveFormatChunk(short channels, uint samplesPerSec)
    {
        sChunkID = "fmt ";
        dwChunkSize = 16;
        wFormatTag = typeof(T) == typeof(float) || typeof(T) == typeof(double) ? 3 : 1;
        wChannels = channels;
        dwSamplesPerSec = samplesPerSec;
        wBitsPerSample = (ushort)(Marshal.SizeOf<T>() * 8);
        wBlockAlign = (ushort)(wChannels * ((wBitsPerSample + 7) / 8));
        dwAvgBytesPerSec = dwSamplesPerSec * wBlockAlign;            
    }
}

public class WaveDataChunk<T> where T: struct, IConvertible
{
    public readonly string sChunkID;     // "data"
    public readonly uint dwChunkSize;    // Length of data chunk in bytes
    public readonly T[] dataArray;  // 8-bit audio

    /// <summary>
    /// Initializes a new data chunk with a specified capacity.
    /// </summary>
    public WaveDataChunk(uint capacity)
    {
        dataArray = new T[capacity];
        dwChunkSize = (uint)(Marshal.SizeOf<T>() * capacity);
        sChunkID = "data";
    }   
}

public void FloatWaveGenerator(WaveExampleType type)
{          
    // Init chunks
    header = new WaveHeader();
    format = new WaveFormatChunk<float>(2, 44100);
    data = new WaveDataChunk<float>(format.dwSamplesPerSec * format.wChannels);            

    // Fill the data array with sample data
    switch (type)
    {
        case WaveExampleType.ExampleSineWave:
            double freq = 440.0f;   // Concert A: 440Hz

            // The "angle" used in the function, adjusted for the number of channels and sample rate.
            // This value is like the period of the wave.
            double t = (Math.PI * 2 * freq) / format.dwSamplesPerSec;

            for (uint i = 0; i < format.dwSamplesPerSec - 1; i++)
            {
                // Fill with a simple sine wave at max amplitude
                for (int channel = 0; channel < format.wChannels; channel++)
                {
                    data.dataArray[i * format.wChannels + channel] = (float)Math.Sin(t * i);
                }                        
            }

            break;
    }          
}

请注意，您需要调整由FloatWaveGenerator使用的变量，并在foreach循环保存数据必须写入正确的数据类型为好。在我离开这个作为练习给你。 :)