/// <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()");
}