/// <summary>
/// Write WAV file header.
/// </summary>
/// <param name="fs">The file stream.</param>
/// <param name="h">The wav file header.</param>
public static void WriteFileHeader(FileStream fs, WavFileHeader h)
{
// Write WAV header.
var b = new BinaryWriter(fs);
// WAVE
b.Write((UInt32)0x46464952); // 0x46464952, "RIFF"
b.Write(h.ChunkSize);
b.Write((UInt32)0x45564157); // 0x45564157, "WAVE"
// fmt
b.Write((UInt32)0x20746d66); // 0x20746d66, "fmt "
b.Write(h.Subchunk1Size);
b.Write(h.AudioFormat);
b.Write(h.NumChannels);
b.Write(h.SampleRate);
b.Write(h.ByteRate);
b.Write(h.BlockAlign);
b.Write(h.BitsPerSample);
// Write PCM data or extensible data if exists.
if (h.Subchunk1Size == 16 && h.AudioFormat == 1)
{
// PCM
b.Write((UInt32)0x61746164); // 0x61746164, "data"
b.Write(h.Subchunk2Size);
}
else if (h.Subchunk1Size > 16 && h.AudioFormat == 0xFFFE)
{
// Write WAVEFORMATEXTENSIBLE
b.Write(h.ExtraParamSize);
b.Write(h.Samples);
b.Write(h.ChannelMask);
b.Write(h.GuidSubFormat.ToByteArray());
b.Write((UInt32)0x61746164); // 0x61746164, "data"
b.Write(h.Subchunk2Size);
}
else
{
throw new Exception("Not supported WAV file header.");
}
}
/// <summary>
/// Get mono WAV file header from multi-channel WAV file.
/// </summary>
/// <param name="h">The wav file header.</param>
/// <returns>The new instance of the <see cref="WavFileHeader"/> struct.</returns>
public static WavFileHeader GetMonoWavFileHeader(WavFileHeader h)
{
// Each mono output file has the same header.
var mh = new WavFileHeader();
// WAVE
mh.ChunkID = (UInt32)0x46464952; // 0x46464952, "RIFF"
mh.ChunkSize = 36 + (h.Subchunk2Size / h.NumChannels); // 36 + SubChunk2Size, 4 + (8 + SubChunk1Size) + (8 + SubChunk2Size)
mh.Format = (UInt32)0x45564157; // 0x45564157, "WAVE"
// fmt
mh.Subchunk1ID = (UInt32)0x20746d66; // 0x20746d66, "fmt "
mh.Subchunk1Size = 16; // 16 for PCM, 40 for WAVEFORMATEXTENSIBLE
mh.AudioFormat = (UInt16)1; // PCM = 1, WAVEFORMATEXTENSIBLE.SubFormat = 0xFFFE
mh.NumChannels = (UInt16)1; // Mono = 1, Stereo = 2, etc.
mh.SampleRate = h.SampleRate; // 8000, 44100, etc.
mh.ByteRate = (UInt32)((h.SampleRate * 1 * h.BitsPerSample) / 8); // SampleRate * NumChannels * BitsPerSample/8
mh.BlockAlign = (UInt16)((1 * h.BitsPerSample) / 8); // NumChannels * BitsPerSample/8
mh.BitsPerSample = h.BitsPerSample; // 8 bits = 8, 16 bits = 16, etc.
// extensible
mh.ExtraParamSize = (UInt16)0;
mh.ChannelMask = (UInt32)0;
mh.GuidSubFormat = new Guid();
// data
mh.Subchunk2ID = (UInt32)0x61746164; // 0x61746164, "data"
mh.Subchunk2Size = h.Subchunk2Size / h.NumChannels; // NumSamples * NumChannels * BitsPerSample/8
// info
mh.IsExtensible = false;
mh.HeaderSize = 44;
mh.TotalSamples = (long)((double)mh.Subchunk2Size / ((double)mh.NumChannels * (double)mh.BitsPerSample / 8));
mh.Duration = (1 / (double)mh.SampleRate) * (double)mh.TotalSamples;
return(mh);
}
/// <summary>
/// Read WAV file header.
/// </summary>
/// <param name="fs">The file stream.</param>
/// <returns>The new instance of the <see cref="WavFileHeader"/> struct.</returns>
public static WavFileHeader ReadFileHeader(FileStream fs)
{
var h = new WavFileHeader()
{
HeaderSize = 0
};
// Read WAV header.
var b = new BinaryReader(fs);
// WAVE
h.ChunkID = b.ReadUInt32(); // 0x46464952, "RIFF"
h.ChunkSize = b.ReadUInt32(); // 36 + SubChunk2Size, 4 + (8 + SubChunk1Size) + (8 + SubChunk2Size)
h.Format = b.ReadUInt32(); // 0x45564157, "WAVE"
h.HeaderSize += 12;
// fmt
h.Subchunk1ID = b.ReadUInt32(); // 0x20746d66, "fmt "
h.Subchunk1Size = b.ReadUInt32(); // 16 for PCM, 40 for WAVEFORMATEXTENSIBLE
h.AudioFormat = b.ReadUInt16(); // PCM = 1, WAVEFORMATEXTENSIBLE.SubFormat = 0xFFFE
h.NumChannels = b.ReadUInt16(); // Mono = 1, Stereo = 2, etc.
h.SampleRate = b.ReadUInt32(); // 8000, 44100, etc.
h.ByteRate = b.ReadUInt32(); // SampleRate * NumChannels * BitsPerSample/8
h.BlockAlign = b.ReadUInt16(); // NumChannels * BitsPerSample/8
h.BitsPerSample = b.ReadUInt16(); // 8 bits = 8, 16 bits = 16, etc.
h.HeaderSize += 24;
// Read PCM data or extensible data if exists.
if (h.Subchunk1Size == 16 && h.AudioFormat == 1)
{
// PCM
h.IsExtensible = false;
// Note: 8-bit samples are stored as unsigned bytes, ranging from 0 to 255. 16-bit samples are stored as 2's-complement signed integers, ranging from -32768 to 32767.
// data
h.Subchunk2ID = b.ReadUInt32(); // 0x61746164, "data"
h.Subchunk2Size = b.ReadUInt32(); // NumSamples * NumChannels * BitsPerSample/8
h.HeaderSize += 8;
}
else if (h.Subchunk1Size > 16 && h.AudioFormat == 0xFFFE)
{
// read WAVEFORMATEXTENSIBLE
h.ExtraParamSize = b.ReadUInt16();
h.HeaderSize += 2;
if (h.ExtraParamSize == 22)
{
// if cbSize is set to 22 => WAVEFORMATEXTENSIBLE
h.IsExtensible = true;
//union {
// WORD wValidBitsPerSample; // bits of precision
// WORD wSamplesPerBlock; // valid if wBitsPerSample==0
// WORD wReserved; // If neither applies, set to zero.
//} Samples;
h.Samples = b.ReadUInt16();
// DWORD dwChannelMask; which channels are present in stream
h.ChannelMask = b.ReadUInt32();
// GUID SubFormat
byte[] subFormat = b.ReadBytes(16);
h.HeaderSize += 22;
// Check sub-format.
h.GuidSubFormat = new Guid(subFormat);
if (h.GuidSubFormat != WavFileHeader.SubTypePCM && h.GuidSubFormat != WavFileHeader.SubTypeIEEE_FLOAT)
{
throw new Exception(String.Format("Not supported WAV file type: {0}", h.GuidSubFormat));
}
// Find "data" chunk.
while (b.PeekChar() != -1)
{
UInt32 chunk = b.ReadUInt32();
h.HeaderSize += 4;
if (chunk == 0x61746164)
{
// "data" chunk
h.Subchunk2ID = chunk; // 0x61746164, "data"
h.Subchunk2Size = b.ReadUInt32(); // NumSamples * NumChannels * BitsPerSample/8
h.HeaderSize += 4;
break;
}
else
{
// Read other non "data" chunks.
UInt32 chunkSize = b.ReadUInt32();
h.HeaderSize += 4;
string chunkName = Encoding.ASCII.GetString(BitConverter.GetBytes(chunk));
byte[] chunkData = b.ReadBytes((int)chunkSize);
h.HeaderSize += (int)chunkSize;
}
}
}
else
{
throw new Exception("Not supported WAV file header.");
}
}
else
{
throw new Exception("Not supported WAV file header.");
}
// Calculate number of total samples.
h.TotalSamples = (long)((double)h.Subchunk2Size / ((double)h.NumChannels * (double)h.BitsPerSample / 8));
// Calculate duration in seconds.
h.Duration = (1 / (double)h.SampleRate) * (double)h.TotalSamples;
return(h);
}
