| 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 | */ |