unsafe void restore_samples_fixed(FlacFrame frame, int ch)
{
FlacSubframeInfo sub = frame.subframes[ch];
AudioSamples.MemCpy(sub.samples, sub.best.residual, sub.best.order);
int *data = sub.samples + sub.best.order;
int *residual = sub.best.residual + sub.best.order;
int data_len = frame.blocksize - sub.best.order;
int s0, s1, s2;
switch (sub.best.order)
{
case 0:
AudioSamples.MemCpy(data, residual, data_len);
break;
case 1:
s1 = data[-1];
for (int i = data_len; i > 0; i--)
{
s1 += *(residual++);
*(data++) = s1;
}
//data[i] = residual[i] + data[i - 1];
break;
case 2:
s2 = data[-2];
s1 = data[-1];
for (int i = data_len; i > 0; i--)
{
s0 = *(residual++) + (s1 << 1) - s2;
*(data++) = s0;
s2 = s1;
s1 = s0;
}
//data[i] = residual[i] + data[i - 1] * 2 - data[i - 2];
break;
case 3:
for (int i = 0; i < data_len; i++)
{
data[i] = residual[i] + (((data[i - 1] - data[i - 2]) << 1) + (data[i - 1] - data[i - 2])) + data[i - 3];
}
break;
case 4:
for (int i = 0; i < data_len; i++)
{
data[i] = residual[i] + ((data[i - 1] + data[i - 3]) << 2) - ((data[i - 2] << 2) + (data[i - 2] << 1)) - data[i - 4];
}
break;
}
}
unsafe void restore_samples_lpc(FlacFrame frame, int ch)
{
FlacSubframeInfo sub = frame.subframes[ch];
ulong csum = 0;
fixed(int *coefs = sub.best.coefs)
{
for (int i = sub.best.order; i > 0; i--)
{
csum += (ulong)Math.Abs(coefs[i - 1]);
}
if ((csum << sub.obits) >= 1UL << 32)
{
lpc.decode_residual_long(sub.best.residual, sub.samples, frame.blocksize, sub.best.order, coefs, sub.best.shift);
}
else
{
lpc.decode_residual(sub.best.residual, sub.samples, frame.blocksize, sub.best.order, coefs, sub.best.shift);
}
}
}