core/ambidefs.cpp


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44


#include "config.h"

#include "ambidefs.h"

#include <cassert>


namespace {

constexpr std::array<float,MaxAmbiOrder+1> Ambi3DDecoderHFScale{{
    1.00000000e+00f, 1.00000000e+00f
}};
constexpr std::array<float,MaxAmbiOrder+1> Ambi3DDecoderHFScale2O{{
    7.45355990e-01f, 1.00000000e+00f, 1.00000000e+00f
}};
constexpr std::array<float,MaxAmbiOrder+1> Ambi3DDecoderHFScale3O{{
    5.89792205e-01f, 8.79693856e-01f, 1.00000000e+00f, 1.00000000e+00f
}};

inline auto& GetDecoderHFScales(uint order) noexcept
{
    if(order >= 3) return Ambi3DDecoderHFScale3O;
    if(order == 2) return Ambi3DDecoderHFScale2O;
    return Ambi3DDecoderHFScale;
}

} // namespace

auto AmbiScale::GetHFOrderScales(const uint in_order, const uint out_order) noexcept
    -> std::array<float,MaxAmbiOrder+1>
{
    std::array<float,MaxAmbiOrder+1> ret{};

    assert(out_order >= in_order);

    const auto &target = GetDecoderHFScales(out_order);
    const auto &input = GetDecoderHFScales(in_order);

    for(size_t i{0};i < in_order+1;++i)
        ret[i] = input[i] / target[i];

    return ret;
}