| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | /* | ||
| 2 | * AAC encoder utilities | ||
| 3 | * Copyright (C) 2015 Rostislav Pehlivanov | ||
| 4 | * | ||
| 5 | * This file is part of FFmpeg. | ||
| 6 | * | ||
| 7 | * FFmpeg is free software; you can redistribute it and/or | ||
| 8 | * modify it under the terms of the GNU Lesser General Public | ||
| 9 | * License as published by the Free Software Foundation; either | ||
| 10 | * version 2.1 of the License, or (at your option) any later version. | ||
| 11 | * | ||
| 12 | * FFmpeg is distributed in the hope that it will be useful, | ||
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
| 15 | * Lesser General Public License for more details. | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU Lesser General Public | ||
| 18 | * License along with FFmpeg; if not, write to the Free Software | ||
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | ||
| 20 | */ | ||
| 21 | |||
| 22 | /** | ||
| 23 | * @file | ||
| 24 | * AAC encoder utilities | ||
| 25 | * @author Rostislav Pehlivanov ( atomnuker gmail com ) | ||
| 26 | */ | ||
| 27 | |||
| 28 | #ifndef AVCODEC_AACENC_UTILS_H | ||
| 29 | #define AVCODEC_AACENC_UTILS_H | ||
| 30 | |||
| 31 | #include "libavutil/ffmath.h" | ||
| 32 | #include "aacenc.h" | ||
| 33 | #include "aacenctab.h" | ||
| 34 | #include "aactab.h" | ||
| 35 | |||
| 36 | #define ROUND_STANDARD 0.4054f | ||
| 37 | #define ROUND_TO_ZERO 0.1054f | ||
| 38 | #define C_QUANT 0.4054f | ||
| 39 | |||
| 40 | 18452 | static inline float pos_pow34(float a) | |
| 41 | { | ||
| 42 | 18452 | return sqrtf(a * sqrtf(a)); | |
| 43 | } | ||
| 44 | |||
| 45 | /** | ||
| 46 | * Quantize one coefficient. | ||
| 47 | * @return absolute value of the quantized coefficient | ||
| 48 | * @see 3GPP TS26.403 5.6.2 "Scalefactor determination" | ||
| 49 | */ | ||
| 50 | 5304965 | static inline int quant(float coef, const float Q, const float rounding) | |
| 51 | { | ||
| 52 | 5304965 | float a = coef * Q; | |
| 53 | 5304965 | return sqrtf(a * sqrtf(a)) + rounding; | |
| 54 | } | ||
| 55 | |||
| 56 | 473187 | static inline float find_max_val(int group_len, int swb_size, const float *scaled) | |
| 57 | { | ||
| 58 | 473187 | float maxval = 0.0f; | |
| 59 | int w2, i; | ||
| 60 |
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960304 | for (w2 = 0; w2 < group_len; w2++) { |
| 61 |
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10562957 | for (i = 0; i < swb_size; i++) { |
| 62 |
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10075840 | maxval = FFMAX(maxval, scaled[w2*128+i]); |
| 63 | } | ||
| 64 | } | ||
| 65 | 473187 | return maxval; | |
| 66 | } | ||
| 67 | |||
| 68 | 6821938 | static inline int find_min_book(float maxval, int sf) | |
| 69 | { | ||
| 70 | 6821938 | float Q34 = ff_aac_pow34sf_tab[POW_SF2_ZERO - sf + SCALE_ONE_POS - SCALE_DIV_512]; | |
| 71 | int qmaxval, cb; | ||
| 72 | 6821938 | qmaxval = maxval * Q34 + C_QUANT; | |
| 73 |
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6821938 | if (qmaxval >= (FF_ARRAY_ELEMS(aac_maxval_cb))) |
| 74 | 760358 | cb = 11; | |
| 75 | else | ||
| 76 | 6061580 | cb = aac_maxval_cb[qmaxval]; | |
| 77 | 6821938 | return cb; | |
| 78 | } | ||
| 79 | |||
| 80 | ✗ | static inline float find_form_factor(int group_len, int swb_size, float thresh, | |
| 81 | const float *scaled, float nzslope) { | ||
| 82 | ✗ | const float iswb_size = 1.0f / swb_size; | |
| 83 | ✗ | const float iswb_sizem1 = 1.0f / (swb_size - 1); | |
| 84 | ✗ | const float ethresh = thresh; | |
| 85 | ✗ | float form = 0.0f, weight = 0.0f; | |
| 86 | int w2, i; | ||
| 87 | ✗ | for (w2 = 0; w2 < group_len; w2++) { | |
| 88 | ✗ | float e = 0.0f, e2 = 0.0f, var = 0.0f, maxval = 0.0f; | |
| 89 | ✗ | float nzl = 0; | |
| 90 | ✗ | for (i = 0; i < swb_size; i++) { | |
| 91 | ✗ | float s = fabsf(scaled[w2*128+i]); | |
| 92 | ✗ | maxval = FFMAX(maxval, s); | |
| 93 | ✗ | e += s; | |
| 94 | ✗ | e2 += s *= s; | |
| 95 | /* We really don't want a hard non-zero-line count, since | ||
| 96 | * even below-threshold lines do add up towards band spectral power. | ||
| 97 | * So, fall steeply towards zero, but smoothly | ||
| 98 | */ | ||
| 99 | ✗ | if (s >= ethresh) { | |
| 100 | ✗ | nzl += 1.0f; | |
| 101 | } else { | ||
| 102 | ✗ | if (nzslope == 2.f) | |
| 103 | ✗ | nzl += (s / ethresh) * (s / ethresh); | |
| 104 | else | ||
| 105 | ✗ | nzl += ff_fast_powf(s / ethresh, nzslope); | |
| 106 | } | ||
| 107 | } | ||
| 108 | ✗ | if (e2 > thresh) { | |
| 109 | float frm; | ||
| 110 | ✗ | e *= iswb_size; | |
| 111 | |||
| 112 | /** compute variance */ | ||
| 113 | ✗ | for (i = 0; i < swb_size; i++) { | |
| 114 | ✗ | float d = fabsf(scaled[w2*128+i]) - e; | |
| 115 | ✗ | var += d*d; | |
| 116 | } | ||
| 117 | ✗ | var = sqrtf(var * iswb_sizem1); | |
| 118 | |||
| 119 | ✗ | e2 *= iswb_size; | |
| 120 | ✗ | frm = e / FFMIN(e+4*var,maxval); | |
| 121 | ✗ | form += e2 * sqrtf(frm) / FFMAX(0.5f,nzl); | |
| 122 | ✗ | weight += e2; | |
| 123 | } | ||
| 124 | } | ||
| 125 | ✗ | if (weight > 0) { | |
| 126 | ✗ | return form / weight; | |
| 127 | } else { | ||
| 128 | ✗ | return 1.0f; | |
| 129 | } | ||
| 130 | } | ||
| 131 | |||
| 132 | /** Return the minimum scalefactor where the quantized coef does not clip. */ | ||
| 133 | 33040 | static inline uint8_t coef2minsf(float coef) | |
| 134 | { | ||
| 135 | 33040 | return av_clip_uint8(log2f(coef)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512); | |
| 136 | } | ||
| 137 | |||
| 138 | /** Return the maximum scalefactor where the quantized coef is not zero. */ | ||
| 139 | static inline uint8_t coef2maxsf(float coef) | ||
| 140 | { | ||
| 141 | return av_clip_uint8(log2f(coef)*4 + 6 + SCALE_ONE_POS - SCALE_DIV_512); | ||
| 142 | } | ||
| 143 | |||
| 144 | /* | ||
| 145 | * Returns the closest possible index to an array of float values, given a value. | ||
| 146 | */ | ||
| 147 | 1137 | static inline int quant_array_idx(const float val, const float *arr, const int num) | |
| 148 | { | ||
| 149 | 1137 | int i, index = 0; | |
| 150 | 1137 | float quant_min_err = INFINITY; | |
| 151 |
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19329 | for (i = 0; i < num; i++) { |
| 152 | 18192 | float error = (val - arr[i])*(val - arr[i]); | |
| 153 |
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18192 | if (error < quant_min_err) { |
| 154 | 2956 | quant_min_err = error; | |
| 155 | 2956 | index = i; | |
| 156 | } | ||
| 157 | } | ||
| 158 | 1137 | return index; | |
| 159 | } | ||
| 160 | |||
| 161 | /** | ||
| 162 | * approximates exp10f(-3.0f*(0.5f + 0.5f * cosf(FFMIN(b,15.5f) / 15.5f))) | ||
| 163 | */ | ||
| 164 | ✗ | static av_always_inline float bval2bmax(float b) | |
| 165 | { | ||
| 166 | ✗ | return 0.001f + 0.0035f * (b*b*b) / (15.5f*15.5f*15.5f); | |
| 167 | } | ||
| 168 | |||
| 169 | /* | ||
| 170 | * Compute a nextband map to be used with SF delta constraint utilities. | ||
| 171 | * The nextband array should contain 128 elements, and positions that don't | ||
| 172 | * map to valid, nonzero bands of the form w*16+g (with w being the initial | ||
| 173 | * window of the window group, only) are left indetermined. | ||
| 174 | */ | ||
| 175 | 2569 | static inline void ff_init_nextband_map(const SingleChannelElement *sce, uint8_t *nextband) | |
| 176 | { | ||
| 177 | 2569 | unsigned char prevband = 0; | |
| 178 | int w, g; | ||
| 179 | /** Just a safe default */ | ||
| 180 |
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331401 | for (g = 0; g < 128; g++) |
| 181 | 328832 | nextband[g] = g; | |
| 182 | |||
| 183 | /** Now really navigate the nonzero band chain */ | ||
| 184 |
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5320 | for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) { |
| 185 |
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125168 | for (g = 0; g < sce->ics.num_swb; g++) { |
| 186 |
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122417 | if (!sce->zeroes[w*16+g] && sce->band_type[w*16+g] < RESERVED_BT) |
| 187 | 112876 | prevband = nextband[prevband] = w*16+g; | |
| 188 | } | ||
| 189 | } | ||
| 190 | 2569 | nextband[prevband] = prevband; /* terminate */ | |
| 191 | 2569 | } | |
| 192 | |||
| 193 | /* | ||
| 194 | * Updates nextband to reflect a removed band (equivalent to | ||
| 195 | * calling ff_init_nextband_map after marking a band as zero) | ||
| 196 | */ | ||
| 197 | static inline void ff_nextband_remove(uint8_t *nextband, int prevband, int band) | ||
| 198 | { | ||
| 199 | nextband[prevband] = nextband[band]; | ||
| 200 | } | ||
| 201 | |||
| 202 | /* | ||
| 203 | * Checks whether the specified band could be removed without inducing | ||
| 204 | * scalefactor delta that violates SF delta encoding constraints. | ||
| 205 | * prev_sf has to be the scalefactor of the previous nonzero, nonspecial | ||
| 206 | * band, in encoding order, or negative if there was no such band. | ||
| 207 | */ | ||
| 208 | 36639 | static inline int ff_sfdelta_can_remove_band(const SingleChannelElement *sce, | |
| 209 | const uint8_t *nextband, int prev_sf, int band) | ||
| 210 | { | ||
| 211 | return prev_sf >= 0 | ||
| 212 |
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36639 | && sce->sf_idx[nextband[band]] >= (prev_sf - SCALE_MAX_DIFF) |
| 213 |
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73278 | && sce->sf_idx[nextband[band]] <= (prev_sf + SCALE_MAX_DIFF); |
| 214 | } | ||
| 215 | |||
| 216 | /* | ||
| 217 | * Checks whether the specified band's scalefactor could be replaced | ||
| 218 | * with another one without violating SF delta encoding constraints. | ||
| 219 | * prev_sf has to be the scalefactor of the previous nonzero, nonsepcial | ||
| 220 | * band, in encoding order, or negative if there was no such band. | ||
| 221 | */ | ||
| 222 | ✗ | static inline int ff_sfdelta_can_replace(const SingleChannelElement *sce, | |
| 223 | const uint8_t *nextband, int prev_sf, int new_sf, int band) | ||
| 224 | { | ||
| 225 | ✗ | return new_sf >= (prev_sf - SCALE_MAX_DIFF) | |
| 226 | ✗ | && new_sf <= (prev_sf + SCALE_MAX_DIFF) | |
| 227 | ✗ | && sce->sf_idx[nextband[band]] >= (new_sf - SCALE_MAX_DIFF) | |
| 228 | ✗ | && sce->sf_idx[nextband[band]] <= (new_sf + SCALE_MAX_DIFF); | |
| 229 | } | ||
| 230 | |||
| 231 | /** | ||
| 232 | * linear congruential pseudorandom number generator | ||
| 233 | * | ||
| 234 | * @param previous_val pointer to the current state of the generator | ||
| 235 | * | ||
| 236 | * @return Returns a 32-bit pseudorandom integer | ||
| 237 | */ | ||
| 238 | 638812 | static av_always_inline int lcg_random(unsigned previous_val) | |
| 239 | { | ||
| 240 | 638812 | union { unsigned u; int s; } v = { previous_val * 1664525u + 1013904223 }; | |
| 241 | 638812 | return v.s; | |
| 242 | } | ||
| 243 | |||
| 244 | #define ERROR_IF(cond, ...) \ | ||
| 245 | if (cond) { \ | ||
| 246 | av_log(avctx, AV_LOG_ERROR, __VA_ARGS__); \ | ||
| 247 | return AVERROR(EINVAL); \ | ||
| 248 | } | ||
| 249 | |||
| 250 | #define WARN_IF(cond, ...) \ | ||
| 251 | if (cond) { \ | ||
| 252 | av_log(avctx, AV_LOG_WARNING, __VA_ARGS__); \ | ||
| 253 | } | ||
| 254 | |||
| 255 | #endif /* AVCODEC_AACENC_UTILS_H */ | ||
| 256 |