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add linear resampler (not activated in code). sounds about the same as the other two (ie, no major bugs) on the opening to Golden Axe

This commit is contained in:
goyuken 2012-08-19 17:46:13 +00:00
parent 4ba8fcf227
commit 2a2caa492c
1 changed files with 25 additions and 0 deletions
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25
BizHawk.Emulation/Sound/YM2612.cs
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@ -1031,6 +1031,7 @@ namespace BizHawk.Emulation.Sound
// downsample from native output rate to 44100.
//CrappyNaiveResampler(nativeSamples, samples);
MaybeBetterDownsampler(nativeSamples, samples);
//LinearDownsampler(nativeSamples, samples);
}
static void CrappyNaiveResampler(short[] input, short[] output)
@ -1052,6 +1053,30 @@ namespace BizHawk.Emulation.Sound
return value - Math.Floor(value);
}
/// <summary>
/// basic linear audio resampler. sampling rate is inferred from buffer sizes
/// </summary>
/// <param name="input">stereo s16</param>
/// <param name="output">stereo s16</param>
static void LinearDownsampler(short[] input, short[] output)
{
double samplefactor = input.Length / (double)output.Length;
for (int i = 0; i < output.Length / 2; i++)
{
// exact position on input stream
double inpos = i * samplefactor;
// selected interpolation points and weights
int pt0 = (int)inpos; // pt1 = pt0 + 1
double wt1 = inpos - pt0; // wt0 = 1 - wt1
double wt0 = 1.0 - wt1;
output[i * 2 + 0] = (short)(input[pt0 * 2 + 0] * wt0 + input[pt0 * 2 + 2] * wt1);
output[i * 2 + 1] = (short)(input[pt0 * 2 + 1] * wt0 + input[pt0 * 2 + 3] * wt1);
}
}
static void MaybeBetterDownsampler(short[] input, short[] output)
{
// This is still not a good resampler. But it's better than the other one. Unsure how much difference it makes.