/// <summary>
/// Returns the highest sample value in a WAV file, as a 16-bit value, regardless of
/// whether the file contains 8-bit or 16-bit audio. If the sample is coming from
/// an 8-bit audio file, the sample will be scaled up from 8-bit to 16-bit.
/// </summary>
/// <param name="pFilename">The audio file name</param>
/// <returns>The highest sample value from the file, as a 16-bit value</returns>
public static short HighestSampleValueAs16Bit(String pFilename)
{
short highestSample = 0;
try
{
WAVFile audioFile = new WAVFile();
if (audioFile.Open(pFilename, WAVFileMode.READ) == "")
{
if (audioFile.BitsPerSample == 8)
{
short sample = 0;
for (int i = 0; i < audioFile.NumSamples; ++i)
{
sample = ScaleByteToShort(audioFile.GetNextSample_8bit());
if (sample > highestSample)
highestSample = sample;
}
}
else if (audioFile.BitsPerSample == 16)
{
short sample = 0;
for (int i = 0; i < audioFile.NumSamples; ++i)
{
sample = audioFile.GetNextSample_16bit();
if (sample > highestSample)
highestSample = sample;
}
}
audioFile.Close();
}
}
catch (Exception)
{
}
return highestSample;
}
/// <summary>
/// Returns the highest sample value in a WAV audio file.
/// The return value is a byte array and will contain one
/// byte if the file contains 8-bit audio or 2 bytes if the file
/// contains 16-bit audio. The return value will be null if
/// the file cannot be opened. If it is known that the audio
/// file contains 16-bit samples, the byte array can be converted
/// to a 16-bit integer using BitConverter.ToInt16().
/// </summary>
/// <param name="pFilename">The name of the WAV file</param>
/// <param name="pBitsPerSample">This will contain the number of bits per sample, or 0 if the file wasn't loaded.</param>
/// <returns>A byte array containing the highest audio sample, or null if the file wasn't loaded.</returns>
public static byte[] HighestSampleValue(String pFilename, out short pBitsPerSample)
{
pBitsPerSample = 0;
byte[] highestSampleValue = null;
WAVFile audioFile = new WAVFile();
try
{
if (audioFile.Open(pFilename, WAVFileMode.READ) == "")
{
pBitsPerSample = audioFile.mBitsPerSample;
if (audioFile.mBitsPerSample == 8)
{
byte sample = 0;
byte highestSample = 0;
for (int i = 0; i < audioFile.NumSamples; ++i)
{
sample = audioFile.GetNextSample_8bit();
if (sample > highestSample)
highestSample = sample;
}
highestSampleValue = new byte[1];
highestSampleValue[0] = highestSample;
}
else if (audioFile.mBitsPerSample == 16)
{
short sample = 0;
short highestSample = 0;
for (int i = 0; i < audioFile.NumSamples; ++i)
{
sample = audioFile.GetNextSample_16bit();
if (sample > highestSample)
highestSample = sample;
}
highestSampleValue = BitConverter.GetBytes(highestSample);
if (!BitConverter.IsLittleEndian)
Array.Reverse(highestSampleValue);
}
audioFile.Close();
}
}
catch (Exception)
{
}
return (highestSampleValue);
}
/// <summary>
/// Adjusts the volume level of a WAV file, saving the adjusted file as a separate file.
/// </summary>
/// <param name="pSrcFilename">The name of the WAV file to adjust</param>
/// <param name="pDestFilename">The name to use for the volume-adjusted WAV file</param>
/// <param name="pMultiplier">The value by which to multiply the audio samples</param>
public static void AdjustVolume_Copy(String pSrcFilename, String pDestFilename, double pMultiplier)
{
// If an empty source or destination file were passed in, then throw an exception.
if (pSrcFilename == "")
throw new WAVFileReadException("Blank filename specified.", "WAVFile.AdjustVolume_Copy()");
if (pDestFilename == "")
throw new WAVFileWriteException("Blank filename specified.", "WAVFile.AdjustVolume_Copy()");
// Open the srouce file
WAVFile srcFile = new WAVFile();
String retval = srcFile.Open(pSrcFilename, WAVFileMode.READ);
if (retval == "")
{
// Check to make sure the input file has a supported number of bits/sample and sample rate. If
// not, then throw an exception.
if (!SupportedBitsPerSample(srcFile.BitsPerSample))
{
WAVFileBitsPerSampleException exc = new WAVFileBitsPerSampleException(pSrcFilename +
" has unsupported bits/sample ("
+ srcFile.BitsPerSample.ToString() + ")",
"WAVFile.AdjustVolume_Copy()", srcFile.BitsPerSample);
srcFile.Close();
throw exc;
}
// Open the destination file and start copying the adjusted audio data to it.
WAVFile destFile = new WAVFile();
destFile.Create(pDestFilename, srcFile.IsStereo, srcFile.SampleRateHz, srcFile.BitsPerSample);
if (srcFile.BitsPerSample == 8)
{
byte sample = 0;
for (int i = 0; i < srcFile.NumSamples; ++i)
{
// Note: Only multiply the sample if pMultiplier is not 1.0 (if the multiplier is
// 1.0, then it would be good to avoid any binary roundoff error).
sample = srcFile.GetNextSample_8bit();
if (pMultiplier != 1.0)
sample = (byte)((double)sample * pMultiplier);
destFile.AddSample_8bit(sample);
}
}
else if (srcFile.BitsPerSample == 16)
{
short sample = 0;
for (int i = 0; i < srcFile.NumSamples; ++i)
{
// Note: Only multiply the sample if pMultiplier is not 1.0 (if the multiplier is
// 1.0, then it would be good to avoid any binary roundoff error).
sample = srcFile.GetNextSample_16bit();
if (pMultiplier != 1.0)
sample = (short)((double)sample * pMultiplier);
destFile.AddSample_16bit(sample);
}
}
srcFile.Close();
destFile.Close();
}
else
throw new WAVFileReadException(retval, "WAVFile.AdjustVolume_Copy()");
}
/// <summary>
/// Converts a WAV file's bits/sample and number of channels to a separate WAV file.
/// </summary>
/// <param name="pSrcFilename">The name of the file to convert</param>
/// <param name="pDestFilename">The destination file name</param>
/// <param name="pBitsPerSample">The destination's number of bits/sample</param>
/// <param name="pStereo">Whether or not the destination should be stereo</param>
/// <param name="pVolumeMultiplier">A multiplier that can be used to adjust the volume of the output audio file</param>
public static void CopyAndConvert(String pSrcFilename, String pDestFilename, short pBitsPerSample, bool pStereo, double pVolumeMultiplier)
{
WAVFile srcFile = new WAVFile();
String retval = srcFile.Open(pSrcFilename, WAVFileMode.READ);
if (retval != "")
throw new WAVFileException(retval, "WAVFile.Convert_Copy()");
WAVFile destFile = new WAVFile();
destFile.Create(pDestFilename, pStereo, srcFile.SampleRateHz, pBitsPerSample);
if ((srcFile.BitsPerSample == 8) && (pBitsPerSample == 8))
{
byte sample = 0;
if (srcFile.IsStereo && !pStereo)
{
// 8-bit to 8-bit, stereo to mono: Average each 2 samples
while (srcFile.NumSamplesRemaining > 0)
{
sample = (byte)((short)((short)srcFile.GetNextSample_8bit() + (short)srcFile.GetNextSample_8bit()) / 2);
if (pVolumeMultiplier != 1.0)
sample = (byte)((double)sample * pVolumeMultiplier);
destFile.AddSample_8bit(sample);
}
}
else if ((srcFile.IsStereo && pStereo) || (!srcFile.IsStereo && !pStereo))
{
// 8-bit to 8-bit, stereo to stereo or mono to mono
while (srcFile.NumSamplesRemaining > 0)
{
sample = srcFile.GetNextSample_8bit();
if (pVolumeMultiplier != 1.0)
sample = (byte)((double)sample * pVolumeMultiplier);
destFile.AddSample_8bit(sample);
}
}
else if (!srcFile.IsStereo && pStereo)
{
// 8-bit to 8-bit, mono to stereo: Write each sample twice
while (srcFile.NumSamplesRemaining > 0)
{
sample = srcFile.GetNextSample_8bit();
if (pVolumeMultiplier != 1.0)
sample = (byte)((double)sample * pVolumeMultiplier);
destFile.AddSample_8bit(sample);
destFile.AddSample_8bit(sample);
}
}
}
else if ((srcFile.BitsPerSample == 8) && (pBitsPerSample == 16))
{
short sample = 0;
if (srcFile.IsStereo && !pStereo)
{
// 8-bit to 16 bit, stereo to mono: Average each 2 samples
while (srcFile.NumSamplesRemaining > 0)
{
sample = (short)((int)((int)srcFile.GetNextSampleAs16Bit() + (int)srcFile.GetNextSampleAs16Bit()) / 2);
if (pVolumeMultiplier != 1.0)
sample = (short)((double)sample * pVolumeMultiplier);
destFile.AddSample_16bit(sample);
}
}
else if ((srcFile.IsStereo && pStereo) || (!srcFile.IsStereo && !pStereo))
{
// 8-bit to 16 bit, stereo to stereo or mono to mono
while (srcFile.NumSamplesRemaining > 0)
{
sample = srcFile.GetNextSampleAs16Bit();
if (pVolumeMultiplier != 1.0)
sample = (short)((double)sample * pVolumeMultiplier);
destFile.AddSample_16bit(sample);
}
}
else if (!srcFile.IsStereo && pStereo)
{
// 8-bit to 16 bit, mono to stereo: Write each sample twice
while (srcFile.NumSamplesRemaining > 0)
{
sample = srcFile.GetNextSampleAs16Bit();
if (pVolumeMultiplier != 1.0)
sample = (short)((double)sample * pVolumeMultiplier);
destFile.AddSample_16bit(sample);
destFile.AddSample_16bit(sample);
}
}
}
else if ((srcFile.BitsPerSample == 16) && (pBitsPerSample == 8))
{
byte sample = 0;
if (srcFile.IsStereo && !pStereo)
{
// 16-bit to 8-bit, stereo to mono: Average each 2 samples
short sample_16bit = 0;
while (srcFile.NumSamplesRemaining > 0)
{
sample_16bit = (short)((int)srcFile.GetNextSample_16bit() + (int)srcFile.GetNextSample_16bit() / 2);
if (pVolumeMultiplier != 1.0)
sample_16bit = (short)((double)sample_16bit * pVolumeMultiplier);
sample = ScaleShortToByte(sample_16bit);
destFile.AddSample_8bit(sample);
}
}
else if ((srcFile.IsStereo && pStereo) || (!srcFile.IsStereo && !pStereo))
{
// 16-bit to 8-bit, stereo to stereo or mono to mono
while (srcFile.NumSamplesRemaining > 0)
{
sample = ScaleShortToByte(srcFile.GetNextSample_16bit());
if (pVolumeMultiplier != 1.0)
sample = (byte)((double)sample * pVolumeMultiplier);
destFile.AddSample_8bit(sample);
}
}
else if (!srcFile.IsStereo && pStereo)
{
// 16-bit to 8-bit, mono to stereo: Write each sample twice
while (srcFile.NumSamplesRemaining > 0)
{
sample = ScaleShortToByte(srcFile.GetNextSample_16bit());
if (pVolumeMultiplier != 1.0)
sample = (byte)((double)sample * pVolumeMultiplier);
destFile.AddSample_8bit(sample);
destFile.AddSample_8bit(sample);
}
}
}
else if ((srcFile.BitsPerSample == 16) && (pBitsPerSample == 16))
{
short sample = 0;
if (srcFile.IsStereo && !pStereo)
{
// 16-bit to 16-bit, stereo to mono: Average each 2 samples
while (srcFile.NumSamplesRemaining > 0)
{
sample = (short)((int)((int)srcFile.GetNextSample_16bit() + (int)srcFile.GetNextSample_16bit()) / 2);
if (pVolumeMultiplier != 1.0)
sample = (short)((double)sample * pVolumeMultiplier);
destFile.AddSample_16bit(sample);
}
}
else if ((srcFile.IsStereo && pStereo) || (!srcFile.IsStereo && !pStereo))
{
// 16-bit to 16-bit, stereo to stereo or mono to mono
while (srcFile.NumSamplesRemaining > 0)
{
sample = srcFile.GetNextSample_16bit();
if (pVolumeMultiplier != 1.0)
sample = (short)((double)sample * pVolumeMultiplier);
destFile.AddSample_16bit(sample);
}
}
else if (!srcFile.IsStereo && pStereo)
{
// 16-bit to 16-bit, mono to stereo: Write each sample twice
while (srcFile.NumSamplesRemaining > 0)
{
sample = srcFile.GetNextSample_16bit();
if (pVolumeMultiplier != 1.0)
sample = (short)((double)sample * pVolumeMultiplier);
destFile.AddSample_16bit(sample);
destFile.AddSample_16bit(sample);
}
}
}
destFile.Close();
srcFile.Close();
}
/// <summary>
/// Changes the volume of a WAV file.
/// </summary>
/// <param name="pFilename">The name of the WAV file to adjust</param>
/// <param name="pMultiplier">The volume multiplier</param>
public static void AdjustVolumeInPlace(String pFilename, double pMultiplier)
{
// If pMultiplier is 1, then we don't need to do anything.
if (pMultiplier == 1.0)
return;
// Open the file
WAVFile audioFile = new WAVFile();
String retval = audioFile.Open(pFilename, WAVFileMode.READ_WRITE);
if (retval == "")
{
// Check to make sure the input file has a supported number of bits/sample and sample rate. If
// not, then throw an exception.
if (!SupportedBitsPerSample(audioFile.BitsPerSample))
{
short bitsPerSample = audioFile.BitsPerSample;
audioFile.Close();
throw new WAVFileBitsPerSampleException(pFilename + " has unsupported bits/sample ("
+ bitsPerSample.ToString() + ")",
"WAVFile.AdjustVolumeInPlace()", bitsPerSample);
}
if (!SupportedSampleRate(audioFile.SampleRateHz))
{
int sampleRate = audioFile.SampleRateHz;
audioFile.Close();
throw new WAVFileSampleRateException(pFilename + " has unsupported sample rate ("
+ sampleRate.ToString() + ")",
"WAVFile.AdjustVolumeInPlace()", sampleRate);
}
// Adjust the file volume
if (audioFile.BitsPerSample == 8)
{
byte sample = 0;
for (int sampleNum = 0; sampleNum < audioFile.NumSamples; ++sampleNum)
{
sample = (byte)((double)audioFile.GetNextSample_8bit() * pMultiplier);
audioFile.SeekToAudioSample(sampleNum);
audioFile.AddSample_8bit(sample);
}
}
else if (audioFile.BitsPerSample == 16)
{
short sample = 0;
for (int sampleNum = 0; sampleNum < audioFile.NumSamples; ++sampleNum)
{
sample = (short)((double)audioFile.GetNextSample_16bit() * pMultiplier);
audioFile.SeekToAudioSample(sampleNum);
audioFile.AddSample_16bit(sample);
}
}
audioFile.Close();
}
else
throw new WAVFileReadException(retval, "WAVFile.AdjustVolumeInPlace()");
}