FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/aacenc_utils.h
Date: 2021-09-16 08:47:15
Exec Total Coverage
Lines: 96 98 98.0%
Branches: 62 66 93.9%

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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 "aac.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 700655 static inline void abs_pow34_v(float *out, const float *in, const int size)
41 {
42 int i;
43
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37194983 for (i = 0; i < size; i++) {
44 36494328 float a = fabsf(in[i]);
45 36494328 out[i] = sqrtf(a * sqrtf(a));
46 }
47 700655 }
48
49 21014 static inline float pos_pow34(float a)
50 {
51 21014 return sqrtf(a * sqrtf(a));
52 }
53
54 /**
55 * Quantize one coefficient.
56 * @return absolute value of the quantized coefficient
57 * @see 3GPP TS26.403 5.6.2 "Scalefactor determination"
58 */
59 1750935 static inline int quant(float coef, const float Q, const float rounding)
60 {
61 1750935 float a = coef * Q;
62 1750935 return sqrtf(a * sqrtf(a)) + rounding;
63 }
64
65 7557065 static inline void quantize_bands(int *out, const float *in, const float *scaled,
66 int size, int is_signed, int maxval, const float Q34,
67 const float rounding)
68 {
69 int i;
70
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162206101 for (i = 0; i < size; i++) {
71 154649036 float qc = scaled[i] * Q34;
72
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154649036 int tmp = (int)FFMIN(qc + rounding, (float)maxval);
73
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154649036 if (is_signed && in[i] < 0.0f) {
74 32324013 tmp = -tmp;
75 }
76 154649036 out[i] = tmp;
77 }
78 7557065 }
79
80 562656 static inline float find_max_val(int group_len, int swb_size, const float *scaled)
81 {
82 562656 float maxval = 0.0f;
83 int w2, i;
84
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1134678 for (w2 = 0; w2 < group_len; w2++) {
85
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12541866 for (i = 0; i < swb_size; i++) {
86
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11969844 maxval = FFMAX(maxval, scaled[w2*128+i]);
87 }
88 }
89 562656 return maxval;
90 }
91
92 14873958 static inline int find_min_book(float maxval, int sf)
93 {
94 14873958 float Q34 = ff_aac_pow34sf_tab[POW_SF2_ZERO - sf + SCALE_ONE_POS - SCALE_DIV_512];
95 int qmaxval, cb;
96 14873958 qmaxval = maxval * Q34 + C_QUANT;
97
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14873958 if (qmaxval >= (FF_ARRAY_ELEMS(aac_maxval_cb)))
98 1257690 cb = 11;
99 else
100 13616268 cb = aac_maxval_cb[qmaxval];
101 14873958 return cb;
102 }
103
104 60486 static inline float find_form_factor(int group_len, int swb_size, float thresh,
105 const float *scaled, float nzslope) {
106 60486 const float iswb_size = 1.0f / swb_size;
107 60486 const float iswb_sizem1 = 1.0f / (swb_size - 1);
108 60486 const float ethresh = thresh;
109 60486 float form = 0.0f, weight = 0.0f;
110 int w2, i;
111
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122188 for (w2 = 0; w2 < group_len; w2++) {
112 61702 float e = 0.0f, e2 = 0.0f, var = 0.0f, maxval = 0.0f;
113 61702 float nzl = 0;
114
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1222358 for (i = 0; i < swb_size; i++) {
115 1160656 float s = fabsf(scaled[w2*128+i]);
116
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1160656 maxval = FFMAX(maxval, s);
117 1160656 e += s;
118 1160656 e2 += s *= s;
119 /* We really don't want a hard non-zero-line count, since
120 * even below-threshold lines do add up towards band spectral power.
121 * So, fall steeply towards zero, but smoothly
122 */
123
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1160656 if (s >= ethresh) {
124 342390 nzl += 1.0f;
125 } else {
126
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818266 if (nzslope == 2.f)
127 368121 nzl += (s / ethresh) * (s / ethresh);
128 else
129 450145 nzl += ff_fast_powf(s / ethresh, nzslope);
130 }
131 }
132
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61702 if (e2 > thresh) {
133 float frm;
134 61492 e *= iswb_size;
135
136 /** compute variance */
137
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1220540 for (i = 0; i < swb_size; i++) {
138 1159048 float d = fabsf(scaled[w2*128+i]) - e;
139 1159048 var += d*d;
140 }
141 61492 var = sqrtf(var * iswb_sizem1);
142
143 61492 e2 *= iswb_size;
144
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61492 frm = e / FFMIN(e+4*var,maxval);
145
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61492 form += e2 * sqrtf(frm) / FFMAX(0.5f,nzl);
146 61492 weight += e2;
147 }
148 }
149
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60486 if (weight > 0) {
150 60438 return form / weight;
151 } else {
152 48 return 1.0f;
153 }
154 }
155
156 /** Return the minimum scalefactor where the quantized coef does not clip. */
157 36239 static inline uint8_t coef2minsf(float coef)
158 {
159 36239 return av_clip_uint8(log2f(coef)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
160 }
161
162 /** Return the maximum scalefactor where the quantized coef is not zero. */
163 static inline uint8_t coef2maxsf(float coef)
164 {
165 return av_clip_uint8(log2f(coef)*4 + 6 + SCALE_ONE_POS - SCALE_DIV_512);
166 }
167
168 /*
169 * Returns the closest possible index to an array of float values, given a value.
170 */
171 500 static inline int quant_array_idx(const float val, const float *arr, const int num)
172 {
173 500 int i, index = 0;
174 500 float quant_min_err = INFINITY;
175
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8500 for (i = 0; i < num; i++) {
176 8000 float error = (val - arr[i])*(val - arr[i]);
177
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8000 if (error < quant_min_err) {
178 1009 quant_min_err = error;
179 1009 index = i;
180 }
181 }
182 500 return index;
183 }
184
185 /**
186 * approximates exp10f(-3.0f*(0.5f + 0.5f * cosf(FFMIN(b,15.5f) / 15.5f)))
187 */
188 5362 static av_always_inline float bval2bmax(float b)
189 {
190 5362 return 0.001f + 0.0035f * (b*b*b) / (15.5f*15.5f*15.5f);
191 }
192
193 /*
194 * Compute a nextband map to be used with SF delta constraint utilities.
195 * The nextband array should contain 128 elements, and positions that don't
196 * map to valid, nonzero bands of the form w*16+g (with w being the initial
197 * window of the window group, only) are left indetermined.
198 */
199 3587 static inline void ff_init_nextband_map(const SingleChannelElement *sce, uint8_t *nextband)
200 {
201 3587 unsigned char prevband = 0;
202 int w, g;
203 /** Just a safe default */
204
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462723 for (g = 0; g < 128; g++)
205 459136 nextband[g] = g;
206
207 /** Now really navigate the nonzero band chain */
208
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7398 for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
209
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176458 for (g = 0; g < sce->ics.num_swb; g++) {
210
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172647 if (!sce->zeroes[w*16+g] && sce->band_type[w*16+g] < RESERVED_BT)
211 143281 prevband = nextband[prevband] = w*16+g;
212 }
213 }
214 3587 nextband[prevband] = prevband; /* terminate */
215 3587 }
216
217 /*
218 * Updates nextband to reflect a removed band (equivalent to
219 * calling ff_init_nextband_map after marking a band as zero)
220 */
221 static inline void ff_nextband_remove(uint8_t *nextband, int prevband, int band)
222 {
223 nextband[prevband] = nextband[band];
224 }
225
226 /*
227 * Checks whether the specified band could be removed without inducing
228 * scalefactor delta that violates SF delta encoding constraints.
229 * prev_sf has to be the scalefactor of the previous nonzero, nonspecial
230 * band, in encoding order, or negative if there was no such band.
231 */
232 47931 static inline int ff_sfdelta_can_remove_band(const SingleChannelElement *sce,
233 const uint8_t *nextband, int prev_sf, int band)
234 {
235 return prev_sf >= 0
236
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47863 && sce->sf_idx[nextband[band]] >= (prev_sf - SCALE_MAX_DIFF)
237
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95794 && sce->sf_idx[nextband[band]] <= (prev_sf + SCALE_MAX_DIFF);
238 }
239
240 /*
241 * Checks whether the specified band's scalefactor could be replaced
242 * with another one without violating SF delta encoding constraints.
243 * prev_sf has to be the scalefactor of the previous nonzero, nonsepcial
244 * band, in encoding order, or negative if there was no such band.
245 */
246 6070 static inline int ff_sfdelta_can_replace(const SingleChannelElement *sce,
247 const uint8_t *nextband, int prev_sf, int new_sf, int band)
248 {
249 6070 return new_sf >= (prev_sf - SCALE_MAX_DIFF)
250
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6070 && new_sf <= (prev_sf + SCALE_MAX_DIFF)
251
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6070 && sce->sf_idx[nextband[band]] >= (new_sf - SCALE_MAX_DIFF)
252
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12140 && sce->sf_idx[nextband[band]] <= (new_sf + SCALE_MAX_DIFF);
253 }
254
255 /**
256 * linear congruential pseudorandom number generator
257 *
258 * @param previous_val pointer to the current state of the generator
259 *
260 * @return Returns a 32-bit pseudorandom integer
261 */
262 904188 static av_always_inline int lcg_random(unsigned previous_val)
263 {
264 904188 union { unsigned u; int s; } v = { previous_val * 1664525u + 1013904223 };
265 904188 return v.s;
266 }
267
268 #define ERROR_IF(cond, ...) \
269 if (cond) { \
270 av_log(avctx, AV_LOG_ERROR, __VA_ARGS__); \
271 return AVERROR(EINVAL); \
272 }
273
274 #define WARN_IF(cond, ...) \
275 if (cond) { \
276 av_log(avctx, AV_LOG_WARNING, __VA_ARGS__); \
277 }
278
279 #endif /* AVCODEC_AACENC_UTILS_H */
280