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Avoid making BSincPointsMax public

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This commit is contained in:
Chris Robinson 2021-03-01 17:41:07 -08:00
parent 9f349c21e7
commit 727503acdb
3 changed files with 30 additions and 19 deletions
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1
alc/alu.cpp
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@ -100,7 +100,6 @@ struct BSincTag;
struct FastBSincTag;
static_assert(MaxResamplerPadding >= BSincPointsMax, "MaxResamplerPadding is too small");
static_assert(!(MaxResamplerPadding&1), "MaxResamplerPadding is not a multiple of two");

6
core/bsinc_defs.h
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@ -7,10 +7,4 @@ constexpr unsigned int BSincScaleCount{1 << BSincScaleBits};
constexpr unsigned int BSincPhaseBits{5};
constexpr unsigned int BSincPhaseCount{1 << BSincPhaseBits};
/* The maximum number of sample points for the bsinc filters. The max points
* includes the doubling for downsampling, so the maximum number of base sample
* points is 24, which is 23rd order.
*/
constexpr unsigned int BSincPointsMax{48};
#endif /* CORE_BSINC_DEFS_H */

42
core/bsinc_tables.cpp
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@ -9,6 +9,7 @@
#include <memory>
#include <stdexcept>
#include "core/mixer/defs.h"
#include "math_defs.h"
@ -36,7 +37,7 @@ constexpr double Sinc(const double x)
* I_0(x) = sum_{k=0}^inf (1 / k!)^2 (x / 2)^(2 k)
* = sum_{k=0}^inf ((x / 2)^k / k!)^2
*/
constexpr double BesselI_0(const double x)
constexpr double BesselI_0(const double x) noexcept
{
/* Start at k=1 since k=0 is trivial. */
const double x2{x / 2.0};
@ -83,7 +84,7 @@ constexpr double Kaiser(const double beta, const double k, const double besseli_
/* Calculates the (normalized frequency) transition width of the Kaiser window.
* Rejection is in dB.
*/
constexpr double CalcKaiserWidth(const double rejection, const uint order)
constexpr double CalcKaiserWidth(const double rejection, const uint order) noexcept
{
if(rejection > 21.19)
return (rejection - 7.95) / (order * 2.285 * al::MathDefs<double>::Tau());
@ -145,21 +146,33 @@ constexpr BSincHeader bsinc24_hdr{60, 23};
* namespace while also being used as non-type template parameters.
*/
#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ < 6
/* The number of sample points is double the a value (rounded up to a multiple
* of 4), and scale index 0 includes the doubling for downsampling. bsinc24 is
* currently the highest quality filter, and will use the most sample points.
*/
constexpr uint BSincPointsMax{(bsinc24_hdr.a[0]*2 + 3) & ~3u};
static_assert(BSincPointsMax <= MaxResamplerPadding, "MaxResamplerPadding is too small");
template<size_t total_size>
struct BSincFilterArray {
alignas(16) std::array<float, total_size> mTable;
const BSincHeader &hdr;
BSincFilterArray(const BSincHeader &hdr)
BSincFilterArray(const BSincHeader &hdr_) : hdr{hdr_}
{
#else
template<const BSincHeader &hdr>
struct BSincFilterArray {
alignas(16) std::array<float, hdr.total_size> mTable;
alignas(16) std::array<float, hdr.total_size> mTable{};
BSincFilterArray()
#endif
{
using filter_type = double[][BSincPhaseCount+1][BSincPointsMax];
auto filter = std::make_unique<filter_type>(BSincScaleCount);
constexpr uint BSincPointsMax{(hdr.a[0]*2 + 3) & ~3u};
static_assert(BSincPointsMax <= MaxResamplerPadding, "MaxResamplerPadding is too small");
#endif
using filter_type = double[BSincPhaseCount+1][BSincPointsMax];
auto filter = std::make_unique<filter_type[]>(BSincScaleCount);
/* Calculate the Kaiser-windowed Sinc filter coefficients for each
* scale and phase index.
@ -169,7 +182,7 @@ struct BSincFilterArray {
const uint m{hdr.a[si] * 2};
const size_t o{(BSincPointsMax-m) / 2};
const double scale{hdr.scaleBase + (hdr.scaleRange * (si+1) / BSincScaleCount)};
const double cutoff{scale - (hdr.scaleBase * std::max(0.5, scale) * 2.0)};
const double cutoff{scale - (hdr.scaleBase * std::max(1.0, scale*2.0))};
const auto a = static_cast<double>(hdr.a[si]);
const double l{a - 1.0/BSincPhaseCount};
@ -247,6 +260,9 @@ struct BSincFilterArray {
}
assert(idx == hdr.total_size);
}
constexpr const BSincHeader &getHeader() const noexcept { return hdr; }
constexpr const float *getTable() const noexcept { return &mTable.front(); }
};
#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ < 6
@ -257,9 +273,11 @@ const BSincFilterArray<bsinc12_hdr> bsinc12_filter{};
const BSincFilterArray<bsinc24_hdr> bsinc24_filter{};
#endif
constexpr BSincTable GenerateBSincTable(const BSincHeader &hdr, const float *tab)
template<typename T>
constexpr BSincTable GenerateBSincTable(const T &filter)
{
BSincTable ret{};
const BSincHeader &hdr = filter.getHeader();
ret.scaleBase = static_cast<float>(hdr.scaleBase);
ret.scaleRange = static_cast<float>(1.0 / hdr.scaleRange);
for(size_t i{0};i < BSincScaleCount;++i)
@ -267,11 +285,11 @@ constexpr BSincTable GenerateBSincTable(const BSincHeader &hdr, const float *tab
ret.filterOffset[0] = 0;
for(size_t i{1};i < BSincScaleCount;++i)
ret.filterOffset[i] = ret.filterOffset[i-1] + ret.m[i-1]*4*BSincPhaseCount;
ret.Tab = tab;
ret.Tab = filter.getTable();
return ret;
}
} // namespace
const BSincTable bsinc12{GenerateBSincTable(bsinc12_hdr, &bsinc12_filter.mTable.front())};
const BSincTable bsinc24{GenerateBSincTable(bsinc24_hdr, &bsinc24_filter.mTable.front())};
const BSincTable bsinc12{GenerateBSincTable(bsinc12_filter)};
const BSincTable bsinc24{GenerateBSincTable(bsinc24_filter)};