/// <summary>
/// パラメータを指定して新しい OverSampling クラスのインスタンスを初期化します。
/// </summary>
/// <param name="samplingRate">サンプリング周波数。これはオーバーサンプリング後の周波数となります。</param>
/// <param name="magnification">サンプリング倍率。</param>
/// <param name="stereo">ステレオである場合は true、モノラルである場合は false。</param>
/// <param name="filterSize">フィルタサイズ。</param>
public OverSampling(double samplingRate, int magnification, bool stereo, int filterSize)
{
if (samplingRate <= 0.0)
throw new ArgumentOutOfRangeException("samplingRate");
if (magnification <= 0)
throw new ArgumentOutOfRangeException("magnification");
if (filterSize <= 0)
throw new ArgumentOutOfRangeException("filterSize");
if (filterSize % 2 != 0)
throw new ArgumentException();
this.samplingRate = samplingRate;
this.magnification = magnification;
this.stereo = stereo;
this.filterSize = filterSize;
this.filter = new SoundFilter(stereo, filterSize);
var filterGenerator = new LowPassFilter()
{
SamplingRate = samplingRate * magnification,
CutoffFrequency = samplingRate / 2 -
FiniteImpulseResponse.GetDelta(samplingRate * magnification, filterSize)
};
double[] impulse = filterGenerator.Generate(filterSize / 2);
Window.Blackman(impulse);
filter.SetFilter(impulse);
}
private void ExportLoop(ExportData data)
{
using (FileStream fs = new FileStream(this.textBox_saveto.Text, FileMode.Create))
using (WaveFormatWriter wfw = new WaveFormatWriter(fs, data.SamplingRate, data.Bit * 8, 2))
{
const int bufferSize = 512;
const int filterSize = 4096;
float[] buffer = new float[bufferSize];
double[] buffer_double = new double[filterSize];
double[] bufferOut = new double[filterSize];
SoundFilter filter = new SoundFilter(true, filterSize);
var filterGenerator = new LowPassFilter()
{
SamplingRate = data.SamplingRate * data.Oversampling,
CutoffFrequency = data.SamplingRate / 2 - ImpulseResponse.GetDelta(data.SamplingRate * data.Oversampling, filterSize)
};
double[] impulse = filterGenerator.Generate(filterSize / 2);
Window.Hanning(impulse);
filter.SetFilter(impulse);
double bufferTime = (buffer.Length / 2.0) / (data.SamplingRate * data.Oversampling);
var filterBuffer = new FilterBuffer<float>(filterSize, da =>
{
if (data.Oversampling > 1)
{
for (int i = 0; i < filterSize; i++)
bufferOut[i] = da[i];
filter.Filtering(bufferOut);
for (int i = 0, j = 0; i < filterSize; i += data.Oversampling * 2)
{
buffer_double[j++] = bufferOut[i];
buffer_double[j++] = bufferOut[i + 1];
}
wfw.Write(buffer_double, 0, (int)Math.Min(filterSize / data.Oversampling, data.FileSize - data.Output));
}
else
wfw.Write(da, 0, filterSize);
data.Output = wfw.WrittenBytes;
});
while (!this.reqEnd && data.FileSize > data.Output)
{
data.Connector.Sequencer.Progress(bufferTime);
data.Connector.Master.Read(buffer, 0, bufferSize);
filterBuffer.Push(buffer);
if (data.SequenceEnded && data.Connector.Master.ToneCount == 0)
this.reqEnd = true;
}
filterBuffer.Close();
this.reqEnd = true;
this.Invoke(new Action(() => button_stop_Click(null, null)));
}
}