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
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
#ifndef AMBIDEFS_H
#define AMBIDEFS_H
#include <array>
#include <cstdint>
/* The maximum number of Ambisonics channels. For a given order (o), the size
* needed will be (o+1)**2, thus zero-order has 1, first-order has 4, second-
* order has 9, third-order has 16, and fourth-order has 25.
*/
#define MAX_AMBI_ORDER 3
constexpr inline size_t AmbiChannelsFromOrder(size_t order) noexcept
{ return (order+1) * (order+1); }
#define MAX_AMBI_CHANNELS AmbiChannelsFromOrder(MAX_AMBI_ORDER)
/* A bitmask of ambisonic channels for 0 to 4th order. This only specifies up
* to 4th order, which is the highest order a 32-bit mask value can specify (a
* 64-bit mask could handle up to 7th order).
*/
#define AMBI_0ORDER_MASK 0x00000001
#define AMBI_1ORDER_MASK 0x0000000f
#define AMBI_2ORDER_MASK 0x000001ff
#define AMBI_3ORDER_MASK 0x0000ffff
#define AMBI_4ORDER_MASK 0x01ffffff
/* A bitmask of ambisonic channels with height information. If none of these
* channels are used/needed, there's no height (e.g. with most surround sound
* speaker setups). This is ACN ordering, with bit 0 being ACN 0, etc.
*/
#define AMBI_PERIPHONIC_MASK (0xfe7ce4)
/* The maximum number of ambisonic channels for 2D (non-periphonic)
* representation. This is 2 per each order above zero-order, plus 1 for zero-
* order. Or simply, o*2 + 1.
*/
constexpr inline size_t Ambi2DChannelsFromOrder(size_t order) noexcept
{ return order*2 + 1; }
#define MAX_AMBI2D_CHANNELS Ambi2DChannelsFromOrder(MAX_AMBI_ORDER)
/* NOTE: These are scale factors as applied to Ambisonics content. Decoder
* coefficients should be divided by these values to get proper scalings.
*/
struct AmbiScale {
static constexpr std::array<float,MAX_AMBI_CHANNELS> FromN3D{{
1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f
}};
static constexpr std::array<float,MAX_AMBI_CHANNELS> FromSN3D{{
1.000000000f, /* ACN 0, sqrt(1) */
1.732050808f, /* ACN 1, sqrt(3) */
1.732050808f, /* ACN 2, sqrt(3) */
1.732050808f, /* ACN 3, sqrt(3) */
2.236067978f, /* ACN 4, sqrt(5) */
2.236067978f, /* ACN 5, sqrt(5) */
2.236067978f, /* ACN 6, sqrt(5) */
2.236067978f, /* ACN 7, sqrt(5) */
2.236067978f, /* ACN 8, sqrt(5) */
2.645751311f, /* ACN 9, sqrt(7) */
2.645751311f, /* ACN 10, sqrt(7) */
2.645751311f, /* ACN 11, sqrt(7) */
2.645751311f, /* ACN 12, sqrt(7) */
2.645751311f, /* ACN 13, sqrt(7) */
2.645751311f, /* ACN 14, sqrt(7) */
2.645751311f, /* ACN 15, sqrt(7) */
}};
static constexpr std::array<float,MAX_AMBI_CHANNELS> FromFuMa{{
1.414213562f, /* ACN 0 (W), sqrt(2) */
1.732050808f, /* ACN 1 (Y), sqrt(3) */
1.732050808f, /* ACN 2 (Z), sqrt(3) */
1.732050808f, /* ACN 3 (X), sqrt(3) */
1.936491673f, /* ACN 4 (V), sqrt(15)/2 */
1.936491673f, /* ACN 5 (T), sqrt(15)/2 */
2.236067978f, /* ACN 6 (R), sqrt(5) */
1.936491673f, /* ACN 7 (S), sqrt(15)/2 */
1.936491673f, /* ACN 8 (U), sqrt(15)/2 */
2.091650066f, /* ACN 9 (Q), sqrt(35/8) */
1.972026594f, /* ACN 10 (O), sqrt(35)/3 */
2.231093404f, /* ACN 11 (M), sqrt(224/45) */
2.645751311f, /* ACN 12 (K), sqrt(7) */
2.231093404f, /* ACN 13 (L), sqrt(224/45) */
1.972026594f, /* ACN 14 (N), sqrt(35)/3 */
2.091650066f, /* ACN 15 (P), sqrt(35/8) */
}};
};
struct AmbiIndex {
static constexpr std::array<uint8_t,MAX_AMBI_CHANNELS> FromFuMa{{
0, /* W */
3, /* X */
1, /* Y */
2, /* Z */
6, /* R */
7, /* S */
5, /* T */
8, /* U */
4, /* V */
12, /* K */
13, /* L */
11, /* M */
14, /* N */
10, /* O */
15, /* P */
9, /* Q */
}};
static constexpr std::array<uint8_t,MAX_AMBI2D_CHANNELS> FromFuMa2D{{
0, /* W */
3, /* X */
1, /* Y */
8, /* U */
4, /* V */
15, /* P */
9, /* Q */
}};
static constexpr std::array<uint8_t,MAX_AMBI_CHANNELS> FromACN{{
0, 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15
}};
static constexpr std::array<uint8_t,MAX_AMBI2D_CHANNELS> From2D{{
0, 1,3, 4,8, 9,15
}};
static constexpr std::array<uint8_t,MAX_AMBI_CHANNELS> OrderFromChannel{{
0, 1,1,1, 2,2,2,2,2, 3,3,3,3,3,3,3,
}};
static constexpr std::array<uint8_t,MAX_AMBI2D_CHANNELS> OrderFrom2DChannel{{
0, 1,1, 2,2, 3,3,
}};
};
#endif /* AMBIDEFS_H */
|
