/// <summary>
/// Method to change the sample rate of active waveWindow
/// </summary>
/// <param name="newRate"></param>
public void changeSampleRate(int newRate)
{
if (newRate == wave.sampleRate)
{
return;
}
for (int channel = 0; channel < wave.channels; channel++)
{
wave.samples[channel] = Formulas.resample(ref wave.samples[channel], wave.sampleRate, newRate);
}
wave.sampleRate = newRate;
updateFreqStatusBar();
calculateDFT();
timeDomain.setSamples(wave.samples);
timeDomain.Invalidate();
}
/// <summary>
/// Method to apply FX effects
/// </summary>
/// <param name="effect"></param>
/// <param name="args"></param>
public void applyDSPFX(EDIT_FX effect, object[] args)
{
int startIndex = Math.Max(timeSelStart, 0);
int endIndex;
if (timeSelEnd != timeSelStart)
{
endIndex = timeSelEnd;
}
else
{
endIndex = wave.getNumSamples();
}
WaveFile data = wave.cutSelection(startIndex, endIndex);
Formulas.ApplyFX(effect, args, ref data);
wave.pasteSelection(startIndex, data.samples);
timeDomain.setSamples(wave.samples);
timeDomain.Invalidate();
invalidPlayer = true;
}
/// <summary>
/// Method to handle user's selection in frequency domain
/// passes selected samples to concolution filter.
/// </summary>
/// <param name="method"></param>
public void filterSelectedFrequencies(FILTERING method = FILTERING.convolution)
{
if (freqSelStart == freqSelEnd)
{
return;
}
double[] filter = new double[fourierN];
for (int fbin = 0; fbin < filter.Length; fbin++)
{
if ((fbin >= freqSelStart && fbin <= freqSelEnd) || (fbin >= fourierN - freqSelEnd && fbin <= fourierN - freqSelStart))
{
filter[fbin] = 0;
}
else
{
filter[fbin] = 1;
}
}
double criticalPoint = 0;
if (method == FILTERING.IIRLowpass)
{
criticalPoint = freqSelStart * SampleRate / fourierN;
}
else
{
criticalPoint = freqSelEnd * SampleRate / fourierN;
}
for (int channel = 0; channel < wave.channels; channel++)
{
switch (method)
{
case FILTERING.convolution:
wave.samples[channel] = Formulas.convolveFilter(ref wave.samples[channel], filter);
break;
case FILTERING.DFT:
wave.samples[channel] = Formulas.dftFilter(wave.samples[channel], filter);
break;
case FILTERING.IIRLowpass: //low pass
wave.samples[channel] = Formulas.IIRFilter(wave.samples[channel], Math.Min(criticalPoint + 5000, SampleRate / 2), Math.Max(0, criticalPoint - 5000), 0, SampleRate);
break;
case FILTERING.IIRHighpass: //high pass
wave.samples[channel] = Formulas.IIRFilter(wave.samples[channel], Math.Max(0, criticalPoint - 7000), Math.Min(criticalPoint + 3000, SampleRate / 2), 1, SampleRate);
break;
default:
MessageBox.Show("Error occured");
break;
}
}
timeDomain.setSamples(wave.samples);
timeDomain.Invalidate();
calculateDFT();
invalidPlayer = true;
}
/// <summary>
/// Method to resample the sample set.
/// Then goes through a lowpass filter
/// </summary>
/// <param name="samples">sample to be changed</param>
/// <param name="originalRate">original samplerate</param>
/// <param name="targetRate">target samplerate</param>
/// <returns></returns>
public static double[] resample(ref double[] samples, int originalRate, int targetRate)
{
double[] extendedSamples, result;
int L, M;
if (targetRate == originalRate)
{
return(samples);
}
else if (targetRate == 2 * originalRate)
{
L = 2; M = 1;
}
else if (targetRate == 4 * originalRate)
{
L = 4; M = 1;
}
else if (targetRate == 8 * originalRate)
{
L = 8; M = 1;
}
else if (targetRate * 2 == originalRate)
{
L = 1; M = 2;
}
else if (targetRate * 4 == originalRate)
{
L = 1; M = 4;
}
else if (targetRate * 8 == originalRate)
{
L = 1; M = 8;
}
else
{
return(null);
}
//used to pad 0's between samples
extendedSamples = new double[samples.Length * L];
int i = 0;
for (int s = 0; s < samples.Length; s++)
{
extendedSamples[i] = samples[s];
i++;
for (int extra = 0; extra < L - 1; extra++)
{
extendedSamples[i] = 0;
i++;
}
}
//lowpass filter
int S = Math.Min(originalRate, targetRate);
extendedSamples = Formulas.IIRFilter(extendedSamples, S / 2 + 5000, S / 2 - 5000, 0, S * 2);
//skips and select every Mth sample.
result = new double[extendedSamples.Length / M];
i = 0;
for (int s = 0; s < extendedSamples.Length; s += M)
{
try
{
result[i++] = extendedSamples[s];
} catch {
}
}
return(result);
}
