public static void WriteWavHeader(Stream output, AudioFormatEx audioFormat, uint rawDataLength)
{
if (audioFormat == null)
throw new ArgumentException("No audio available."); //this may occur if there is no audio hardware
if (audioFormat.WaveFormat != WaveFormatType.Pcm)
throw new ArgumentException("Only PCM coding is supported.");
var bwOutput = new BinaryWriter(output);
// Write down the WAV header.
// Refer to http://technology.niagarac.on.ca/courses/ctec1631/WavFileFormat.html (broken link: see https://ccrma.stanford.edu/courses/422/projects/WaveFormat/ instead)
// for details on the format.
// Note that we use ToCharArray() when writing fixed strings
// to force using the char[] overload because
// Write(string) writes the string prefixed by its length.
// -- RIFF chunk
bwOutput.Write("RIFF".ToCharArray());
// Total Length Of Package To Follow
// Computed as data length plus the header length without the data
// we have written so far and this data (44 - 4 ("RIFF") - 4 (this number))
bwOutput.Write(rawDataLength + WAV_HEADER_SIZE - 4 - 4);
bwOutput.Write("WAVE".ToCharArray()); //RIFF data type
// -- FORMAT chunk
bwOutput.Write("fmt ".ToCharArray());
// Length Of FORMAT Chunk (Binary, always 0x10)
bwOutput.Write((uint) 0x10);
// Always 0x01
bwOutput.Write((ushort) 0x01);
// Channel Numbers (Always 0x01=Mono, 0x02=Stereo)
bwOutput.Write((ushort) audioFormat.Channels);
// Sample Rate (Binary, in Hz)
bwOutput.Write((uint) audioFormat.SamplesPerSecond);
// Calculate Bytes/Sample and Bytes/Second
var bytesPerSample = (ushort) (audioFormat.BitsPerSample*audioFormat.Channels/8);
// 1=8 bit Mono, 2=8 bit Stereo or 16 bit Mono, 4=16 bit Stereo
var bytesPerSecond = (uint) (bytesPerSample*audioFormat.SamplesPerSecond);
// Bytes Per Second
bwOutput.Write(bytesPerSecond);
// Bytes Per Sample
bwOutput.Write(bytesPerSample);
// Bits Per Sample
bwOutput.Write((ushort) audioFormat.BitsPerSample);
// -- DATA chunk
bwOutput.Write("data".ToCharArray());
// Length Of Data To Follow
bwOutput.Write(rawDataLength);
}
public static void SavePcmToWav(Stream[] rawData, Stream output, AudioFormatEx audioFormat, uint offset = 0,
long maxLength = -1)
//Saves WAV concatenating multiple raw data streams (each optionally starting at offset and cropped at maxLength)
{
// Get total raw data stream length
uint len = 0;
foreach (Stream s in rawData)
{
uint lengthAfterOffset = (uint) s.Length - offset;
len += (lengthAfterOffset <= maxLength) ? lengthAfterOffset : (uint) maxLength;
}
// Write WAV header
WriteWavHeader(output, audioFormat, len);
// Write raw PCM data streams in sequence
foreach (Stream s in rawData)
WriteRawData(s, output, offset, maxLength);
}
public static AudioFormat PickAudioFormat(ReadOnlyCollection<AudioFormat> audioFormats,
AudioFormatEx desiredFormat)
{
return audioFormats.FirstOrDefault(audioFormat => desiredFormat.Equals(audioFormat));
}
public static void SavePcmToWav(Stream rawData, Stream output, AudioFormatEx audioFormat, uint offset = 0,
long maxLength = -1) //TODO: add optional maxSeconds parameter
{
WriteWavHeader(output, audioFormat, (uint) rawData.Length);
WriteRawData(rawData, output, offset, maxLength); //raw PCM data
}
/// <summary>
/// Determines whether the specified <see cref="System.Object" }, is equal to this instance.
/// </summary>
/// <param name="obj">The <see cref="System.Object" /> to compare with this instance.</param>
/// <returns>
/// <c>true</c> if the specified <see cref="System.Object" /> is equal to this instance; otherwise, <c>false</c>.
/// </returns>
public override bool Equals(object obj)
{
if (obj == null) return false;
AudioFormatEx formatObj = null;
if (obj.GetType() == typeof (AudioFormatEx))
formatObj = (AudioFormatEx) obj;
else if (obj.GetType() == typeof (AudioFormat))
formatObj = new AudioFormatEx((AudioFormat) obj);
else if (obj.GetType() == typeof (WAVEFORMATEX))
formatObj = new AudioFormatEx((WAVEFORMATEX) obj);
return (_format == formatObj._format) &&
(_bitsPerSample == formatObj._bitsPerSample) &&
(_channels == formatObj._channels) &&
(_samplesPerSecond == formatObj._samplesPerSecond);
}
