blob: 5d532e06732760cb94425a822dc4995867e8c237
1 | /* |
2 | * This file is part of FFmpeg. |
3 | * |
4 | * FFmpeg is free software; you can redistribute it and/or |
5 | * modify it under the terms of the GNU Lesser General Public |
6 | * License as published by the Free Software Foundation; either |
7 | * version 2.1 of the License, or (at your option) any later version. |
8 | * |
9 | * FFmpeg is distributed in the hope that it will be useful, |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | * Lesser General Public License for more details. |
13 | * |
14 | * You should have received a copy of the GNU Lesser General Public |
15 | * License along with FFmpeg; if not, write to the Free Software |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
17 | */ |
18 | |
19 | #include <stdint.h> |
20 | #include "libavutil/avutil.h" |
21 | #include "mathops.h" |
22 | |
23 | #undef FUNC |
24 | #undef sum_type |
25 | #undef MUL |
26 | #undef CLIP |
27 | #undef FSUF |
28 | |
29 | #define FUNC(n) AV_JOIN(n ## _, SAMPLE_SIZE) |
30 | |
31 | #if SAMPLE_SIZE == 32 |
32 | # define sum_type int64_t |
33 | # define MUL(a, b) MUL64(a, b) |
34 | # define CLIP(x) av_clipl_int32(x) |
35 | #else |
36 | # define sum_type int32_t |
37 | # define MUL(a, b) ((a) * (b)) |
38 | # define CLIP(x) (x) |
39 | #endif |
40 | |
41 | #define LPC1(x) { \ |
42 | int c = coefs[(x)-1]; \ |
43 | p0 += MUL(c, s); \ |
44 | s = smp[i-(x)+1]; \ |
45 | p1 += MUL(c, s); \ |
46 | } |
47 | |
48 | static av_always_inline void FUNC(lpc_encode_unrolled)(int32_t *res, |
49 | const int32_t *smp, int len, int order, |
50 | const int32_t *coefs, int shift, int big) |
51 | { |
52 | int i; |
53 | for (i = order; i < len; i += 2) { |
54 | int s = smp[i-order]; |
55 | sum_type p0 = 0, p1 = 0; |
56 | if (big) { |
57 | switch (order) { |
58 | case 32: LPC1(32) |
59 | case 31: LPC1(31) |
60 | case 30: LPC1(30) |
61 | case 29: LPC1(29) |
62 | case 28: LPC1(28) |
63 | case 27: LPC1(27) |
64 | case 26: LPC1(26) |
65 | case 25: LPC1(25) |
66 | case 24: LPC1(24) |
67 | case 23: LPC1(23) |
68 | case 22: LPC1(22) |
69 | case 21: LPC1(21) |
70 | case 20: LPC1(20) |
71 | case 19: LPC1(19) |
72 | case 18: LPC1(18) |
73 | case 17: LPC1(17) |
74 | case 16: LPC1(16) |
75 | case 15: LPC1(15) |
76 | case 14: LPC1(14) |
77 | case 13: LPC1(13) |
78 | case 12: LPC1(12) |
79 | case 11: LPC1(11) |
80 | case 10: LPC1(10) |
81 | case 9: LPC1( 9) |
82 | LPC1( 8) |
83 | LPC1( 7) |
84 | LPC1( 6) |
85 | LPC1( 5) |
86 | LPC1( 4) |
87 | LPC1( 3) |
88 | LPC1( 2) |
89 | LPC1( 1) |
90 | } |
91 | } else { |
92 | switch (order) { |
93 | case 8: LPC1( 8) |
94 | case 7: LPC1( 7) |
95 | case 6: LPC1( 6) |
96 | case 5: LPC1( 5) |
97 | case 4: LPC1( 4) |
98 | case 3: LPC1( 3) |
99 | case 2: LPC1( 2) |
100 | case 1: LPC1( 1) |
101 | } |
102 | } |
103 | res[i ] = smp[i ] - CLIP(p0 >> shift); |
104 | res[i+1] = smp[i+1] - CLIP(p1 >> shift); |
105 | } |
106 | } |
107 | |
108 | static void FUNC(flac_lpc_encode_c)(int32_t *res, const int32_t *smp, int len, |
109 | int order, const int32_t *coefs, int shift) |
110 | { |
111 | int i; |
112 | for (i = 0; i < order; i++) |
113 | res[i] = smp[i]; |
114 | #if CONFIG_SMALL |
115 | for (i = order; i < len; i += 2) { |
116 | int j; |
117 | int s = smp[i]; |
118 | sum_type p0 = 0, p1 = 0; |
119 | for (j = 0; j < order; j++) { |
120 | int c = coefs[j]; |
121 | p1 += MUL(c, s); |
122 | s = smp[i-j-1]; |
123 | p0 += MUL(c, s); |
124 | } |
125 | res[i ] = smp[i ] - CLIP(p0 >> shift); |
126 | res[i+1] = smp[i+1] - CLIP(p1 >> shift); |
127 | } |
128 | #else |
129 | switch (order) { |
130 | case 1: FUNC(lpc_encode_unrolled)(res, smp, len, 1, coefs, shift, 0); break; |
131 | case 2: FUNC(lpc_encode_unrolled)(res, smp, len, 2, coefs, shift, 0); break; |
132 | case 3: FUNC(lpc_encode_unrolled)(res, smp, len, 3, coefs, shift, 0); break; |
133 | case 4: FUNC(lpc_encode_unrolled)(res, smp, len, 4, coefs, shift, 0); break; |
134 | case 5: FUNC(lpc_encode_unrolled)(res, smp, len, 5, coefs, shift, 0); break; |
135 | case 6: FUNC(lpc_encode_unrolled)(res, smp, len, 6, coefs, shift, 0); break; |
136 | case 7: FUNC(lpc_encode_unrolled)(res, smp, len, 7, coefs, shift, 0); break; |
137 | case 8: FUNC(lpc_encode_unrolled)(res, smp, len, 8, coefs, shift, 0); break; |
138 | default: FUNC(lpc_encode_unrolled)(res, smp, len, order, coefs, shift, 1); break; |
139 | } |
140 | #endif |
141 | } |
142 | |
143 | /* Comment for clarity/de-obfuscation. |
144 | * |
145 | * for (int i = order; i < len; i++) { |
146 | * int32_t p = 0; |
147 | * for (int j = 0; j < order; j++) { |
148 | * int c = coefs[j]; |
149 | * int s = smp[(i-1)-j]; |
150 | * p += c*s; |
151 | * } |
152 | * res[i] = smp[i] - (p >> shift); |
153 | * } |
154 | * |
155 | * The CONFIG_SMALL code above simplifies to this, in the case of SAMPLE_SIZE |
156 | * not being equal to 32 (at the present time that means for 16-bit audio). The |
157 | * code above does 2 samples per iteration. Commit bfdd5bc (made all the way |
158 | * back in 2007) says that way is faster. |
159 | */ |
160 |