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path: root/libavfilter/af_replaygain.c (plain)
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1/*
2 * Copyright (c) 1998 - 2009 Conifer Software
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
22 * @file
23 * ReplayGain scanner
24 */
25
26#include "libavutil/avassert.h"
27#include "libavutil/channel_layout.h"
28#include "audio.h"
29#include "avfilter.h"
30#include "internal.h"
31
32#define HISTOGRAM_SLOTS 12000
33#define BUTTER_ORDER 2
34#define YULE_ORDER 10
35
36typedef struct ReplayGainFreqInfo {
37 int sample_rate;
38 double BYule[YULE_ORDER + 1];
39 double AYule[YULE_ORDER + 1];
40 double BButter[BUTTER_ORDER + 1];
41 double AButter[BUTTER_ORDER + 1];
42} ReplayGainFreqInfo;
43
44static const ReplayGainFreqInfo freqinfos[] =
45{
46 {
47 192000,
48 { 0.01184742123123, -0.04631092400086, 0.06584226961238,
49 -0.02165588522478, -0.05656260778952, 0.08607493592760,
50 -0.03375544339786, -0.04216579932754, 0.06416711490648,
51 -0.03444708260844, 0.00697275872241 },
52 { 1.00000000000000, -5.24727318348167, 10.60821585192244,
53 -8.74127665810413, -1.33906071371683, 8.07972882096606,
54 -5.46179918950847, 0.54318070652536, 0.87450969224280,
55 -0.34656083539754, 0.03034796843589 },
56 { 0.99653501465135, -1.99307002930271, 0.99653501465135 },
57 { 1.00000000000000, -1.99305802314321, 0.99308203546221 },
58 },
59 {
60 176400,
61 { 0.00268568524529, -0.00852379426080, 0.00852704191347,
62 0.00146116310295, -0.00950855828762, 0.00625449515499,
63 0.00116183868722, -0.00362461417136, 0.00203961000134,
64 -0.00050664587933, 0.00004327455427 },
65 { 1.00000000000000, -5.57512782763045, 12.44291056065794,
66 -12.87462799681221, 3.08554846961576, 6.62493459880692,
67 -7.07662766313248, 2.51175542736441, 0.06731510802735,
68 -0.24567753819213, 0.03961404162376 },
69 { 0.99622916581118, -1.99245833162236, 0.99622916581118 },
70 { 1.00000000000000, -1.99244411238133, 0.99247255086339 },
71 },
72 {
73 144000,
74 { 0.00639682359450, -0.02556437970955, 0.04230854400938,
75 -0.03722462201267, 0.01718514827295, 0.00610592243009,
76 -0.03065965747365, 0.04345745003539, -0.03298592681309,
77 0.01320937236809, -0.00220304127757 },
78 { 1.00000000000000, -6.14814623523425, 15.80002457141566,
79 -20.78487587686937, 11.98848552310315, 3.36462015062606,
80 -10.22419868359470, 6.65599702146473, -1.67141861110485,
81 -0.05417956536718, 0.07374767867406 },
82 { 0.99538268958706, -1.99076537917413, 0.99538268958706 },
83 { 1.00000000000000, -1.99074405950505, 0.99078669884321 },
84 },
85 {
86 128000,
87 { 0.00553120584305, -0.02112620545016, 0.03549076243117,
88 -0.03362498312306, 0.01425867248183, 0.01344686928787,
89 -0.03392770787836, 0.03464136459530, -0.02039116051549,
90 0.00667420794705, -0.00093763762995 },
91 { 1.00000000000000, -6.14581710839925, 16.04785903675838,
92 -22.19089131407749, 15.24756471580286, -0.52001440400238,
93 -8.00488641699940, 6.60916094768855, -2.37856022810923,
94 0.33106947986101, 0.00459820832036 },
95 { 0.99480702681278, -1.98961405362557, 0.99480702681278 },
96 { 1.00000000000000, -1.98958708647324, 0.98964102077790 },
97 },
98 {
99 112000,
100 { 0.00528778718259, -0.01893240907245, 0.03185982561867,
101 -0.02926260297838, 0.00715743034072, 0.01985743355827,
102 -0.03222614850941, 0.02565681978192, -0.01210662313473,
103 0.00325436284541, -0.00044173593001 },
104 { 1.00000000000000, -6.24932108456288, 17.42344320538476,
105 -27.86819709054896, 26.79087344681326,-13.43711081485123,
106 -0.66023612948173, 6.03658091814935, -4.24926577030310,
107 1.40829268709186, -0.19480852628112 },
108 { 0.99406737810867, -1.98813475621734, 0.99406737810867 },
109 { 1.00000000000000, -1.98809955990514, 0.98816995252954 },
110 },
111 {
112 96000,
113 { 0.00588138296683, -0.01613559730421, 0.02184798954216,
114 -0.01742490405317, 0.00464635643780, 0.01117772513205,
115 -0.02123865824368, 0.01959354413350, -0.01079720643523,
116 0.00352183686289, -0.00063124341421 },
117 { 1.00000000000000, -5.97808823642008, 16.21362507964068,
118 -25.72923730652599, 25.40470663139513,-14.66166287771134,
119 2.81597484359752, 2.51447125969733, -2.23575306985286,
120 0.75788151036791, -0.10078025199029 },
121 { 0.99308203517541, -1.98616407035082, 0.99308203517541 },
122 { 1.00000000000000, -1.98611621154089, 0.98621192916075 },
123 },
124 {
125 88200,
126 { 0.02667482047416, -0.11377479336097, 0.23063167910965,
127 -0.30726477945593, 0.33188520686529, -0.33862680249063,
128 0.31807161531340, -0.23730796929880, 0.12273894790371,
129 -0.03840017967282, 0.00549673387936 },
130 { 1.00000000000000, -6.31836451657302, 18.31351310801799,
131 -31.88210014815921, 36.53792146976740,-28.23393036467559,
132 14.24725258227189, -4.04670980012854, 0.18865757280515,
133 0.25420333563908, -0.06012333531065 },
134 { 0.99247255046129, -1.98494510092259, 0.99247255046129 },
135 { 1.00000000000000, -1.98488843762335, 0.98500176422183 },
136 },
137 {
138 64000,
139 { 0.02613056568174, -0.08128786488109, 0.14937282347325,
140 -0.21695711675126, 0.25010286673402, -0.23162283619278,
141 0.17424041833052, -0.10299599216680, 0.04258696481981,
142 -0.00977952936493, 0.00105325558889 },
143 { 1.00000000000000, -5.73625477092119, 16.15249794355035,
144 -29.68654912464508, 39.55706155674083,-39.82524556246253,
145 30.50605345013009,-17.43051772821245, 7.05154573908017,
146 -1.80783839720514, 0.22127840210813 },
147 { 0.98964101933472, -1.97928203866944, 0.98964101933472 },
148 { 1.00000000000000, -1.97917472731009, 0.97938935002880 },
149 },
150 {
151 56000,
152 { 0.03144914734085, -0.06151729206963, 0.08066788708145,
153 -0.09737939921516, 0.08943210803999, -0.06989984672010,
154 0.04926972841044, -0.03161257848451, 0.01456837493506,
155 -0.00316015108496, 0.00132807215875 },
156 { 1.00000000000000, -4.87377313090032, 12.03922160140209,
157 -20.10151118381395, 25.10388534415171,-24.29065560815903,
158 18.27158469090663,-10.45249552560593, 4.30319491872003,
159 -1.13716992070185, 0.14510733527035 },
160 { 0.98816995007392, -1.97633990014784, 0.98816995007392 },
161 { 1.00000000000000, -1.97619994516973, 0.97647985512594 },
162 },
163 {
164 48000,
165 { 0.03857599435200, -0.02160367184185, -0.00123395316851,
166 -0.00009291677959, -0.01655260341619, 0.02161526843274,
167 -0.02074045215285, 0.00594298065125, 0.00306428023191,
168 0.00012025322027, 0.00288463683916 },
169 { 1.00000000000000, -3.84664617118067, 7.81501653005538,
170 -11.34170355132042, 13.05504219327545,-12.28759895145294,
171 9.48293806319790, -5.87257861775999, 2.75465861874613,
172 -0.86984376593551, 0.13919314567432 },
173 { 0.98621192462708, -1.97242384925416, 0.98621192462708 },
174 { 1.00000000000000, -1.97223372919527, 0.97261396931306 },
175 },
176 {
177 44100,
178 { 0.05418656406430, -0.02911007808948, -0.00848709379851,
179 -0.00851165645469, -0.00834990904936, 0.02245293253339,
180 -0.02596338512915, 0.01624864962975, -0.00240879051584,
181 0.00674613682247, -0.00187763777362 },
182 { 1.00000000000000, -3.47845948550071, 6.36317777566148,
183 -8.54751527471874, 9.47693607801280, -8.81498681370155,
184 6.85401540936998, -4.39470996079559, 2.19611684890774,
185 -0.75104302451432, 0.13149317958808 },
186 { 0.98500175787242, -1.97000351574484, 0.98500175787242 },
187 { 1.00000000000000, -1.96977855582618, 0.97022847566350 },
188 },
189 {
190 37800,
191 { 0.08717879977844, -0.01000374016172, -0.06265852122368,
192 -0.01119328800950, -0.00114279372960, 0.02081333954769,
193 -0.01603261863207, 0.01936763028546, 0.00760044736442,
194 -0.00303979112271, -0.00075088605788 },
195 { 1.00000000000000, -2.62816311472146, 3.53734535817992,
196 -3.81003448678921, 3.91291636730132, -3.53518605896288,
197 2.71356866157873, -1.86723311846592, 1.12075382367659,
198 -0.48574086886890, 0.11330544663849 },
199 { 0.98252400815195, -1.96504801630391, 0.98252400815195 },
200 { 1.00000000000000, -1.96474258269041, 0.96535344991740 },
201 },
202 {
203 32000,
204 { 0.15457299681924, -0.09331049056315, -0.06247880153653,
205 0.02163541888798, -0.05588393329856, 0.04781476674921,
206 0.00222312597743, 0.03174092540049, -0.01390589421898,
207 0.00651420667831, -0.00881362733839 },
208 { 1.00000000000000, -2.37898834973084, 2.84868151156327,
209 -2.64577170229825, 2.23697657451713, -1.67148153367602,
210 1.00595954808547, -0.45953458054983, 0.16378164858596,
211 -0.05032077717131, 0.02347897407020 },
212 { 0.97938932735214, -1.95877865470428, 0.97938932735214 },
213 { 1.00000000000000, -1.95835380975398, 0.95920349965459 },
214 },
215 {
216 24000,
217 { 0.30296907319327, -0.22613988682123, -0.08587323730772,
218 0.03282930172664, -0.00915702933434, -0.02364141202522,
219 -0.00584456039913, 0.06276101321749, -0.00000828086748,
220 0.00205861885564, -0.02950134983287 },
221 { 1.00000000000000, -1.61273165137247, 1.07977492259970,
222 -0.25656257754070, -0.16276719120440, -0.22638893773906,
223 0.39120800788284, -0.22138138954925, 0.04500235387352,
224 0.02005851806501, 0.00302439095741 },
225 { 0.97531843204928, -1.95063686409857, 0.97531843204928 },
226 { 1.00000000000000, -1.95002759149878, 0.95124613669835 },
227 },
228 {
229 22050,
230 { 0.33642304856132, -0.25572241425570, -0.11828570177555,
231 0.11921148675203, -0.07834489609479, -0.00469977914380,
232 -0.00589500224440, 0.05724228140351, 0.00832043980773,
233 -0.01635381384540, -0.01760176568150 },
234 { 1.00000000000000, -1.49858979367799, 0.87350271418188,
235 0.12205022308084, -0.80774944671438, 0.47854794562326,
236 -0.12453458140019, -0.04067510197014, 0.08333755284107,
237 -0.04237348025746, 0.02977207319925 },
238 { 0.97316523498161, -1.94633046996323, 0.97316523498161 },
239 { 1.00000000000000, -1.94561023566527, 0.94705070426118 },
240 },
241 {
242 18900,
243 { 0.38524531015142, -0.27682212062067, -0.09980181488805,
244 0.09951486755646, -0.08934020156622, -0.00322369330199,
245 -0.00110329090689, 0.03784509844682, 0.01683906213303,
246 -0.01147039862572, -0.01941767987192 },
247 { 1.00000000000000, -1.29708918404534, 0.90399339674203,
248 -0.29613799017877, -0.42326645916207, 0.37934887402200,
249 -0.37919795944938, 0.23410283284785, -0.03892971758879,
250 0.00403009552351, 0.03640166626278 },
251 { 0.96535326815829, -1.93070653631658, 0.96535326815829 },
252 { 1.00000000000000, -1.92950577983524, 0.93190729279793 },
253 },
254 {
255 16000,
256 { 0.44915256608450, -0.14351757464547, -0.22784394429749,
257 -0.01419140100551, 0.04078262797139, -0.12398163381748,
258 0.04097565135648, 0.10478503600251, -0.01863887810927,
259 -0.03193428438915, 0.00541907748707 },
260 { 1.00000000000000, -0.62820619233671, 0.29661783706366,
261 -0.37256372942400, 0.00213767857124, -0.42029820170918,
262 0.22199650564824, 0.00613424350682, 0.06747620744683,
263 0.05784820375801, 0.03222754072173 },
264 { 0.96454515552826, -1.92909031105652, 0.96454515552826 },
265 { 1.00000000000000, -1.92783286977036, 0.93034775234268 },
266 },
267 {
268 12000,
269 { 0.56619470757641, -0.75464456939302, 0.16242137742230,
270 0.16744243493672, -0.18901604199609, 0.30931782841830,
271 -0.27562961986224, 0.00647310677246, 0.08647503780351,
272 -0.03788984554840, -0.00588215443421 },
273 { 1.00000000000000, -1.04800335126349, 0.29156311971249,
274 -0.26806001042947, 0.00819999645858, 0.45054734505008,
275 -0.33032403314006, 0.06739368333110, -0.04784254229033,
276 0.01639907836189, 0.01807364323573 },
277 { 0.96009142950541, -1.92018285901082, 0.96009142950541 },
278 { 1.00000000000000, -1.91858953033784, 0.92177618768381 },
279 },
280 {
281 11025,
282 { 0.58100494960553, -0.53174909058578, -0.14289799034253,
283 0.17520704835522, 0.02377945217615, 0.15558449135573,
284 -0.25344790059353, 0.01628462406333, 0.06920467763959,
285 -0.03721611395801, -0.00749618797172 },
286 { 1.00000000000000, -0.51035327095184, -0.31863563325245,
287 -0.20256413484477, 0.14728154134330, 0.38952639978999,
288 -0.23313271880868, -0.05246019024463, -0.02505961724053,
289 0.02442357316099, 0.01818801111503 },
290 { 0.95856916599601, -1.91713833199203, 0.95856916599601 },
291 { 1.00000000000000, -1.91542108074780, 0.91885558323625 },
292 },
293 {
294 8000,
295 { 0.53648789255105, -0.42163034350696, -0.00275953611929,
296 0.04267842219415, -0.10214864179676, 0.14590772289388,
297 -0.02459864859345, -0.11202315195388, -0.04060034127000,
298 0.04788665548180, -0.02217936801134 },
299 { 1.00000000000000, -0.25049871956020, -0.43193942311114,
300 -0.03424681017675, -0.04678328784242, 0.26408300200955,
301 0.15113130533216, -0.17556493366449, -0.18823009262115,
302 0.05477720428674, 0.04704409688120 },
303 { 0.94597685600279, -1.89195371200558, 0.94597685600279 },
304 { 1.00000000000000, -1.88903307939452, 0.89487434461664 },
305 },
306};
307
308typedef struct ReplayGainContext {
309 uint32_t histogram[HISTOGRAM_SLOTS];
310 float peak;
311 int yule_hist_i, butter_hist_i;
312 const double *yule_coeff_a;
313 const double *yule_coeff_b;
314 const double *butter_coeff_a;
315 const double *butter_coeff_b;
316 float yule_hist_a[256];
317 float yule_hist_b[256];
318 float butter_hist_a[256];
319 float butter_hist_b[256];
320} ReplayGainContext;
321
322static int query_formats(AVFilterContext *ctx)
323{
324 AVFilterFormats *formats = NULL;
325 AVFilterChannelLayouts *layout = NULL;
326 int i, ret;
327
328 if ((ret = ff_add_format (&formats, AV_SAMPLE_FMT_FLT )) < 0 ||
329 (ret = ff_set_common_formats (ctx , formats )) < 0 ||
330 (ret = ff_add_channel_layout (&layout , AV_CH_LAYOUT_STEREO)) < 0 ||
331 (ret = ff_set_common_channel_layouts (ctx , layout )) < 0)
332 return ret;
333
334 formats = NULL;
335 for (i = 0; i < FF_ARRAY_ELEMS(freqinfos); i++) {
336 if ((ret = ff_add_format(&formats, freqinfos[i].sample_rate)) < 0)
337 return ret;
338 }
339
340 return ff_set_common_samplerates(ctx, formats);
341}
342
343static int config_input(AVFilterLink *inlink)
344{
345 AVFilterContext *ctx = inlink->dst;
346 ReplayGainContext *s = ctx->priv;
347 int i;
348
349 for (i = 0; i < FF_ARRAY_ELEMS(freqinfos); i++) {
350 if (freqinfos[i].sample_rate == inlink->sample_rate)
351 break;
352 }
353 av_assert0(i < FF_ARRAY_ELEMS(freqinfos));
354
355 s->yule_coeff_a = freqinfos[i].AYule;
356 s->yule_coeff_b = freqinfos[i].BYule;
357 s->butter_coeff_a = freqinfos[i].AButter;
358 s->butter_coeff_b = freqinfos[i].BButter;
359
360 s->yule_hist_i = 20;
361 s->butter_hist_i = 4;
362 inlink->partial_buf_size =
363 inlink->min_samples =
364 inlink->max_samples = inlink->sample_rate / 20;
365
366 return 0;
367}
368
369/*
370 * Update largest absolute sample value.
371 */
372static void calc_stereo_peak(const float *samples, int nb_samples,
373 float *peak_p)
374{
375 float peak = 0.0;
376
377 while (nb_samples--) {
378 if (samples[0] > peak)
379 peak = samples[0];
380 else if (-samples[0] > peak)
381 peak = -samples[0];
382
383 if (samples[1] > peak)
384 peak = samples[1];
385 else if (-samples[1] > peak)
386 peak = -samples[1];
387
388 samples += 2;
389 }
390
391 *peak_p = FFMAX(peak, *peak_p);
392}
393
394/*
395 * Calculate stereo RMS level. Minimum value is about -100 dB for
396 * digital silence. The 90 dB offset is to compensate for the
397 * normalized float range and 3 dB is for stereo samples.
398 */
399static double calc_stereo_rms(const float *samples, int nb_samples)
400{
401 int count = nb_samples;
402 double sum = 1e-16;
403
404 while (count--) {
405 sum += samples[0] * samples[0] + samples[1] * samples[1];
406 samples += 2;
407 }
408
409 return 10 * log10 (sum / nb_samples) + 90.0 - 3.0;
410}
411
412/*
413 * Optimized implementation of 2nd-order IIR stereo filter.
414 */
415static void butter_filter_stereo_samples(ReplayGainContext *s,
416 float *samples, int nb_samples)
417{
418 const double *coeff_a = s->butter_coeff_a;
419 const double *coeff_b = s->butter_coeff_b;
420 float *hist_a = s->butter_hist_a;
421 float *hist_b = s->butter_hist_b;
422 double left, right;
423 int i, j;
424
425 i = s->butter_hist_i;
426
427 // If filter history is very small magnitude, clear it completely
428 // to prevent denormals from rattling around in there forever
429 // (slowing us down).
430
431 for (j = -4; j < 0; ++j)
432 if (fabs(hist_a[i + j]) > 1e-10 || fabs(hist_b[i + j]) > 1e-10)
433 break;
434
435 if (!j) {
436 memset(s->butter_hist_a, 0, sizeof(s->butter_hist_a));
437 memset(s->butter_hist_b, 0, sizeof(s->butter_hist_b));
438 }
439
440 while (nb_samples--) {
441 left = (hist_b[i ] = samples[0]) * coeff_b[0];
442 right = (hist_b[i + 1] = samples[1]) * coeff_b[0];
443 left += hist_b[i - 2] * coeff_b[1] - hist_a[i - 2] * coeff_a[1];
444 right += hist_b[i - 1] * coeff_b[1] - hist_a[i - 1] * coeff_a[1];
445 left += hist_b[i - 4] * coeff_b[2] - hist_a[i - 4] * coeff_a[2];
446 right += hist_b[i - 3] * coeff_b[2] - hist_a[i - 3] * coeff_a[2];
447 samples[0] = hist_a[i ] = (float) left;
448 samples[1] = hist_a[i + 1] = (float) right;
449 samples += 2;
450
451 if ((i += 2) == 256) {
452 memcpy(hist_a, hist_a + 252, sizeof(*hist_a) * 4);
453 memcpy(hist_b, hist_b + 252, sizeof(*hist_b) * 4);
454 i = 4;
455 }
456 }
457
458 s->butter_hist_i = i;
459}
460
461/*
462 * Optimized implementation of 10th-order IIR stereo filter.
463 */
464static void yule_filter_stereo_samples(ReplayGainContext *s, const float *src,
465 float *dst, int nb_samples)
466{
467 const double *coeff_a = s->yule_coeff_a;
468 const double *coeff_b = s->yule_coeff_b;
469 float *hist_a = s->yule_hist_a;
470 float *hist_b = s->yule_hist_b;
471 double left, right;
472 int i, j;
473
474 i = s->yule_hist_i;
475
476 // If filter history is very small magnitude, clear it completely to
477 // prevent denormals from rattling around in there forever
478 // (slowing us down).
479
480 for (j = -20; j < 0; ++j)
481 if (fabs(hist_a[i + j]) > 1e-10 || fabs(hist_b[i + j]) > 1e-10)
482 break;
483
484 if (!j) {
485 memset(s->yule_hist_a, 0, sizeof(s->yule_hist_a));
486 memset(s->yule_hist_b, 0, sizeof(s->yule_hist_b));
487 }
488
489 while (nb_samples--) {
490 left = (hist_b[i] = src[0]) * coeff_b[0];
491 right = (hist_b[i + 1] = src[1]) * coeff_b[0];
492 left += hist_b[i - 2] * coeff_b[ 1] - hist_a[i - 2] * coeff_a[1 ];
493 right += hist_b[i - 1] * coeff_b[ 1] - hist_a[i - 1] * coeff_a[1 ];
494 left += hist_b[i - 4] * coeff_b[ 2] - hist_a[i - 4] * coeff_a[2 ];
495 right += hist_b[i - 3] * coeff_b[ 2] - hist_a[i - 3] * coeff_a[2 ];
496 left += hist_b[i - 6] * coeff_b[ 3] - hist_a[i - 6] * coeff_a[3 ];
497 right += hist_b[i - 5] * coeff_b[ 3] - hist_a[i - 5] * coeff_a[3 ];
498 left += hist_b[i - 8] * coeff_b[ 4] - hist_a[i - 8] * coeff_a[4 ];
499 right += hist_b[i - 7] * coeff_b[ 4] - hist_a[i - 7] * coeff_a[4 ];
500 left += hist_b[i - 10] * coeff_b[ 5] - hist_a[i - 10] * coeff_a[5 ];
501 right += hist_b[i - 9] * coeff_b[ 5] - hist_a[i - 9] * coeff_a[5 ];
502 left += hist_b[i - 12] * coeff_b[ 6] - hist_a[i - 12] * coeff_a[6 ];
503 right += hist_b[i - 11] * coeff_b[ 6] - hist_a[i - 11] * coeff_a[6 ];
504 left += hist_b[i - 14] * coeff_b[ 7] - hist_a[i - 14] * coeff_a[7 ];
505 right += hist_b[i - 13] * coeff_b[ 7] - hist_a[i - 13] * coeff_a[7 ];
506 left += hist_b[i - 16] * coeff_b[ 8] - hist_a[i - 16] * coeff_a[8 ];
507 right += hist_b[i - 15] * coeff_b[ 8] - hist_a[i - 15] * coeff_a[8 ];
508 left += hist_b[i - 18] * coeff_b[ 9] - hist_a[i - 18] * coeff_a[9 ];
509 right += hist_b[i - 17] * coeff_b[ 9] - hist_a[i - 17] * coeff_a[9 ];
510 left += hist_b[i - 20] * coeff_b[10] - hist_a[i - 20] * coeff_a[10];
511 right += hist_b[i - 19] * coeff_b[10] - hist_a[i - 19] * coeff_a[10];
512 dst[0] = hist_a[i ] = (float)left;
513 dst[1] = hist_a[i + 1] = (float)right;
514 src += 2;
515 dst += 2;
516
517 if ((i += 2) == 256) {
518 memcpy(hist_a, hist_a + 236, sizeof(*hist_a) * 20);
519 memcpy(hist_b, hist_b + 236, sizeof(*hist_b) * 20);
520 i = 20;
521 }
522 }
523
524 s->yule_hist_i = i;
525}
526
527/*
528 * Calculate the ReplayGain value from the specified loudness histogram;
529 * clip to -24 / +64 dB.
530 */
531static float calc_replaygain(uint32_t *histogram)
532{
533 uint32_t loud_count = 0, total_windows = 0;
534 float gain;
535 int i;
536
537 for (i = 0; i < HISTOGRAM_SLOTS; i++)
538 total_windows += histogram [i];
539
540 while (i--)
541 if ((loud_count += histogram [i]) * 20 >= total_windows)
542 break;
543
544 gain = (float)(64.54 - i / 100.0);
545
546 return av_clipf(gain, -24.0, 64.0);
547}
548
549static int filter_frame(AVFilterLink *inlink, AVFrame *in)
550{
551 AVFilterContext *ctx = inlink->dst;
552 AVFilterLink *outlink = ctx->outputs[0];
553 ReplayGainContext *s = ctx->priv;
554 uint32_t level;
555 AVFrame *out;
556
557 out = ff_get_audio_buffer(inlink, in->nb_samples);
558 if (!out) {
559 av_frame_free(&in);
560 return AVERROR(ENOMEM);
561 }
562
563 calc_stereo_peak((float *)in->data[0],
564 in->nb_samples, &s->peak);
565 yule_filter_stereo_samples(s, (const float *)in->data[0],
566 (float *)out->data[0],
567 out->nb_samples);
568 butter_filter_stereo_samples(s, (float *)out->data[0],
569 out->nb_samples);
570 level = (uint32_t)floor(100 * calc_stereo_rms((float *)out->data[0],
571 out->nb_samples));
572 level = av_clip(level, 0, HISTOGRAM_SLOTS - 1);
573
574 s->histogram[level]++;
575
576 av_frame_free(&out);
577 return ff_filter_frame(outlink, in);
578}
579
580static av_cold void uninit(AVFilterContext *ctx)
581{
582 ReplayGainContext *s = ctx->priv;
583 float gain = calc_replaygain(s->histogram);
584
585 av_log(ctx, AV_LOG_INFO, "track_gain = %+.2f dB\n", gain);
586 av_log(ctx, AV_LOG_INFO, "track_peak = %.6f\n", s->peak);
587}
588
589static const AVFilterPad replaygain_inputs[] = {
590 {
591 .name = "default",
592 .type = AVMEDIA_TYPE_AUDIO,
593 .filter_frame = filter_frame,
594 .config_props = config_input,
595 },
596 { NULL }
597};
598
599static const AVFilterPad replaygain_outputs[] = {
600 {
601 .name = "default",
602 .type = AVMEDIA_TYPE_AUDIO,
603 },
604 { NULL }
605};
606
607AVFilter ff_af_replaygain = {
608 .name = "replaygain",
609 .description = NULL_IF_CONFIG_SMALL("ReplayGain scanner."),
610 .query_formats = query_formats,
611 .uninit = uninit,
612 .priv_size = sizeof(ReplayGainContext),
613 .inputs = replaygain_inputs,
614 .outputs = replaygain_outputs,
615};
616
generated by cgit at 2024-05-17 08:26:39 (GMT)