public static void Iht8x864Add(ReadOnlySpan <int> input, Span <byte> dest, int stride, int txType)
{
int i, j;
Span <int> output = stackalloc int[8 * 8];
Span <int> outptr = output;
Span <int> tempIn = stackalloc int[8];
Span <int> tempOut = stackalloc int[8];
Transform2D ht = Iht8[txType];
// Inverse transform row vectors
for (i = 0; i < 8; ++i)
{
ht.Rows(input, outptr);
input = input.Slice(8);
outptr = outptr.Slice(8);
}
// Inverse transform column vectors
for (i = 0; i < 8; ++i)
{
for (j = 0; j < 8; ++j)
{
tempIn[j] = output[j * 8 + i];
}
ht.Cols(tempIn, tempOut);
for (j = 0; j < 8; ++j)
{
dest[j * stride + i] = ClipPixelAdd(dest[j * stride + i], BitUtils.RoundPowerOfTwo(tempOut[j], 5));
}
}
}
public static void Iht16x16256Add(ReadOnlySpan <int> input, Span <byte> dest, int stride, int txType)
{
int i, j;
Span <int> output = stackalloc int[16 * 16];
Span <int> outptr = output;
Span <int> tempIn = stackalloc int[16];
Span <int> tempOut = stackalloc int[16];
Transform2D ht = Iht16[txType];
// Rows
for (i = 0; i < 16; ++i)
{
ht.Rows(input, outptr);
input = input.Slice(16);
outptr = outptr.Slice(16);
}
// Columns
for (i = 0; i < 16; ++i)
{
for (j = 0; j < 16; ++j)
{
tempIn[j] = output[j * 16 + i];
}
ht.Cols(tempIn, tempOut);
for (j = 0; j < 16; ++j)
{
dest[j * stride + i] = ClipPixelAdd(dest[j * stride + i], BitUtils.RoundPowerOfTwo(tempOut[j], 6));
}
}
}