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Keep bsinc filter quality more consistent between scales

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This generates the filters using the proper size and scale. The 'a' divisor
should represent the +/- sample range (and thus be a whole number), with the
number of sample points being double that. Increasing the filter size to a
multiple of 4 (for SIMD) can be done by padding in 0s afterward.
This commit is contained in:
Chris Robinson
2017-08-17 17:47:35 -07:00
parent 080c076643
commit 5048956ff0
2 changed files with 553 additions and 551 deletions
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Alc/bsinc_inc.c
+544 -544
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File diff suppressed because it is too large Load Diff
utils/bsincgen.c
+9 -7
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@@ -161,11 +161,9 @@ static void BsiGenerateTables()
for(si = 0; si < BSINC_SCALE_COUNT; si++)
{
const double scale = scaleBase + (scaleRange * si / (BSINC_SCALE_COUNT - 1));
const double a = MinDouble(BSINC_POINTS_MIN, BSINC_POINTS_MIN / (2.0 * scale));
int m = 2 * (int)floor(a);
// Make sure the number of points is a multiple of 4 (for SSE).
m += ~(m - 1) & 3;
const double a = MinDouble(floor(BSINC_POINTS_MIN / (2.0 * scale)),
BSINC_POINTS_MIN);
int m = 2 * (int)a;
mt[si] = m;
at[si] = a;
@@ -241,6 +239,10 @@ static void BsiGenerateTables()
}
}
// Make sure the number of points is a multiple of 4 (for SIMD).
for(si = 0; si < BSINC_SCALE_COUNT; si++)
mt[si] = (mt[si]+3) & ~3;
// Calculate the table size.
i = 0;
for(si = 0; si < BSINC_SCALE_COUNT; si++)
@@ -331,8 +333,8 @@ static void Sinc4GenerateTables(void)
const double scaleBase = width / 2.0;
const double scaleRange = 1.0 - scaleBase;
const double scale = scaleBase + scaleRange;
const double a = MinDouble(4.0, 4.0 / (2.0*scale));
const int m = 2 * (int)floor(a);
const double a = MinDouble(4.0, floor(4.0 / (2.0*scale)));
const int m = 2 * (int)a;
const int l = (m/2) - 1;
int pi;
for(pi = 0;pi < FRACTIONONE;pi++)