libavfilter/af_replaygain.c
c9660999
 /*
  * Copyright (c) 1998 - 2009 Conifer Software
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**
  * @file
  * ReplayGain scanner
  */
 
 #include "libavutil/avassert.h"
 #include "libavutil/channel_layout.h"
 #include "audio.h"
 #include "avfilter.h"
 #include "internal.h"
 
 #define HISTOGRAM_SLOTS 12000
 #define BUTTER_ORDER        2
 #define YULE_ORDER         10
 
 typedef struct ReplayGainFreqInfo {
     int    sample_rate;
     double BYule[YULE_ORDER + 1];
     double AYule[YULE_ORDER + 1];
     double BButter[BUTTER_ORDER + 1];
     double AButter[BUTTER_ORDER + 1];
 } ReplayGainFreqInfo;
 
 static const ReplayGainFreqInfo freqinfos[] =
 {
     {
         192000,
         {  0.01184742123123, -0.04631092400086,  0.06584226961238,
           -0.02165588522478, -0.05656260778952,  0.08607493592760,
           -0.03375544339786, -0.04216579932754,  0.06416711490648,
           -0.03444708260844,  0.00697275872241 },
         {  1.00000000000000, -5.24727318348167, 10.60821585192244,
           -8.74127665810413, -1.33906071371683,  8.07972882096606,
           -5.46179918950847,  0.54318070652536,  0.87450969224280,
           -0.34656083539754,  0.03034796843589 },
         {  0.99653501465135, -1.99307002930271,  0.99653501465135 },
         {  1.00000000000000, -1.99305802314321,  0.99308203546221 },
     },
     {
         176400,
         {  0.00268568524529, -0.00852379426080,  0.00852704191347,
            0.00146116310295, -0.00950855828762,  0.00625449515499,
            0.00116183868722, -0.00362461417136,  0.00203961000134,
           -0.00050664587933,  0.00004327455427 },
         {  1.00000000000000, -5.57512782763045, 12.44291056065794,
          -12.87462799681221,  3.08554846961576,  6.62493459880692,
           -7.07662766313248,  2.51175542736441,  0.06731510802735,
           -0.24567753819213,  0.03961404162376 },
         {  0.99622916581118, -1.99245833162236,  0.99622916581118 },
         {  1.00000000000000, -1.99244411238133,  0.99247255086339 },
     },
     {
         144000,
         {  0.00639682359450, -0.02556437970955,  0.04230854400938,
           -0.03722462201267,  0.01718514827295,  0.00610592243009,
           -0.03065965747365,  0.04345745003539, -0.03298592681309,
            0.01320937236809, -0.00220304127757 },
         {  1.00000000000000, -6.14814623523425, 15.80002457141566,
          -20.78487587686937, 11.98848552310315,  3.36462015062606,
          -10.22419868359470,  6.65599702146473, -1.67141861110485,
           -0.05417956536718,  0.07374767867406 },
         {  0.99538268958706, -1.99076537917413,  0.99538268958706 },
         {  1.00000000000000, -1.99074405950505,  0.99078669884321 },
     },
     {
         128000,
         {  0.00553120584305, -0.02112620545016,  0.03549076243117,
           -0.03362498312306,  0.01425867248183,  0.01344686928787,
           -0.03392770787836,  0.03464136459530, -0.02039116051549,
            0.00667420794705, -0.00093763762995 },
         {  1.00000000000000, -6.14581710839925, 16.04785903675838,
          -22.19089131407749, 15.24756471580286, -0.52001440400238,
           -8.00488641699940,  6.60916094768855, -2.37856022810923,
            0.33106947986101,  0.00459820832036 },
         {  0.99480702681278, -1.98961405362557,  0.99480702681278 },
         {  1.00000000000000, -1.98958708647324,  0.98964102077790 },
     },
     {
         112000,
         {  0.00528778718259, -0.01893240907245,  0.03185982561867,
           -0.02926260297838,  0.00715743034072,  0.01985743355827,
           -0.03222614850941,  0.02565681978192, -0.01210662313473,
            0.00325436284541, -0.00044173593001 },
         {  1.00000000000000, -6.24932108456288, 17.42344320538476,
          -27.86819709054896, 26.79087344681326,-13.43711081485123,
           -0.66023612948173,  6.03658091814935, -4.24926577030310,
            1.40829268709186, -0.19480852628112 },
         {  0.99406737810867, -1.98813475621734,  0.99406737810867 },
         {  1.00000000000000, -1.98809955990514,  0.98816995252954 },
     },
     {
         96000,
         {  0.00588138296683, -0.01613559730421,  0.02184798954216,
           -0.01742490405317,  0.00464635643780,  0.01117772513205,
           -0.02123865824368,  0.01959354413350, -0.01079720643523,
            0.00352183686289, -0.00063124341421 },
         {  1.00000000000000, -5.97808823642008, 16.21362507964068,
          -25.72923730652599, 25.40470663139513,-14.66166287771134,
            2.81597484359752,  2.51447125969733, -2.23575306985286,
            0.75788151036791, -0.10078025199029 },
         {  0.99308203517541, -1.98616407035082,  0.99308203517541 },
         {  1.00000000000000, -1.98611621154089,  0.98621192916075 },
     },
     {
         88200,
         {  0.02667482047416, -0.11377479336097,  0.23063167910965,
           -0.30726477945593,  0.33188520686529, -0.33862680249063,
            0.31807161531340, -0.23730796929880,  0.12273894790371,
           -0.03840017967282,  0.00549673387936 },
         {  1.00000000000000, -6.31836451657302, 18.31351310801799,
          -31.88210014815921, 36.53792146976740,-28.23393036467559,
           14.24725258227189, -4.04670980012854,  0.18865757280515,
            0.25420333563908, -0.06012333531065 },
         {  0.99247255046129, -1.98494510092259,  0.99247255046129 },
         {  1.00000000000000, -1.98488843762335,  0.98500176422183 },
     },
     {
         64000,
         {  0.02613056568174, -0.08128786488109,  0.14937282347325,
           -0.21695711675126,  0.25010286673402, -0.23162283619278,
            0.17424041833052, -0.10299599216680,  0.04258696481981,
           -0.00977952936493,  0.00105325558889 },
         {  1.00000000000000, -5.73625477092119, 16.15249794355035,
          -29.68654912464508, 39.55706155674083,-39.82524556246253,
           30.50605345013009,-17.43051772821245,  7.05154573908017,
           -1.80783839720514,  0.22127840210813 },
         {  0.98964101933472, -1.97928203866944,  0.98964101933472 },
         {  1.00000000000000, -1.97917472731009,  0.97938935002880 },
     },
     {
         56000,
         {  0.03144914734085, -0.06151729206963,  0.08066788708145,
           -0.09737939921516,  0.08943210803999, -0.06989984672010,
            0.04926972841044, -0.03161257848451,  0.01456837493506,
           -0.00316015108496,  0.00132807215875 },
         {  1.00000000000000, -4.87377313090032, 12.03922160140209,
          -20.10151118381395, 25.10388534415171,-24.29065560815903,
           18.27158469090663,-10.45249552560593,  4.30319491872003,
           -1.13716992070185,  0.14510733527035 },
         {  0.98816995007392, -1.97633990014784,  0.98816995007392 },
         {  1.00000000000000, -1.97619994516973,  0.97647985512594 },
     },
     {
         48000,
         {  0.03857599435200, -0.02160367184185, -0.00123395316851,
           -0.00009291677959, -0.01655260341619,  0.02161526843274,
           -0.02074045215285,  0.00594298065125,  0.00306428023191,
            0.00012025322027,  0.00288463683916 },
         {  1.00000000000000, -3.84664617118067,  7.81501653005538,
          -11.34170355132042, 13.05504219327545,-12.28759895145294,
            9.48293806319790, -5.87257861775999,  2.75465861874613,
           -0.86984376593551,  0.13919314567432 },
         {  0.98621192462708, -1.97242384925416,  0.98621192462708 },
         {  1.00000000000000, -1.97223372919527,  0.97261396931306 },
     },
     {
         44100,
         {  0.05418656406430, -0.02911007808948, -0.00848709379851,
           -0.00851165645469, -0.00834990904936,  0.02245293253339,
           -0.02596338512915,  0.01624864962975, -0.00240879051584,
            0.00674613682247, -0.00187763777362 },
         {  1.00000000000000, -3.47845948550071,  6.36317777566148,
           -8.54751527471874,  9.47693607801280, -8.81498681370155,
            6.85401540936998, -4.39470996079559,  2.19611684890774,
           -0.75104302451432,  0.13149317958808 },
         {  0.98500175787242, -1.97000351574484,  0.98500175787242 },
         {  1.00000000000000, -1.96977855582618,  0.97022847566350 },
     },
     {
         37800,
         {  0.08717879977844, -0.01000374016172, -0.06265852122368,
           -0.01119328800950, -0.00114279372960,  0.02081333954769,
           -0.01603261863207,  0.01936763028546,  0.00760044736442,
           -0.00303979112271, -0.00075088605788 },
         {  1.00000000000000, -2.62816311472146,  3.53734535817992,
           -3.81003448678921,  3.91291636730132, -3.53518605896288,
            2.71356866157873, -1.86723311846592,  1.12075382367659,
           -0.48574086886890,  0.11330544663849 },
         {  0.98252400815195, -1.96504801630391,  0.98252400815195 },
         {  1.00000000000000, -1.96474258269041,  0.96535344991740 },
     },
     {
         32000,
         {  0.15457299681924, -0.09331049056315, -0.06247880153653,
            0.02163541888798, -0.05588393329856,  0.04781476674921,
            0.00222312597743,  0.03174092540049, -0.01390589421898,
            0.00651420667831, -0.00881362733839 },
         {  1.00000000000000, -2.37898834973084,  2.84868151156327,
           -2.64577170229825,  2.23697657451713, -1.67148153367602,
            1.00595954808547, -0.45953458054983,  0.16378164858596,
           -0.05032077717131,  0.02347897407020 },
         {  0.97938932735214, -1.95877865470428,  0.97938932735214 },
         {  1.00000000000000, -1.95835380975398,  0.95920349965459 },
     },
     {
         24000,
         {  0.30296907319327, -0.22613988682123, -0.08587323730772,
            0.03282930172664, -0.00915702933434, -0.02364141202522,
           -0.00584456039913,  0.06276101321749, -0.00000828086748,
            0.00205861885564, -0.02950134983287 },
         {  1.00000000000000, -1.61273165137247,  1.07977492259970,
           -0.25656257754070, -0.16276719120440, -0.22638893773906,
            0.39120800788284, -0.22138138954925,  0.04500235387352,
            0.02005851806501,  0.00302439095741 },
         {  0.97531843204928, -1.95063686409857,  0.97531843204928 },
         {  1.00000000000000, -1.95002759149878,  0.95124613669835 },
     },
     {
         22050,
         {  0.33642304856132, -0.25572241425570, -0.11828570177555,
            0.11921148675203, -0.07834489609479, -0.00469977914380,
           -0.00589500224440,  0.05724228140351,  0.00832043980773,
           -0.01635381384540, -0.01760176568150 },
         {  1.00000000000000, -1.49858979367799,  0.87350271418188,
            0.12205022308084, -0.80774944671438,  0.47854794562326,
           -0.12453458140019, -0.04067510197014,  0.08333755284107,
           -0.04237348025746,  0.02977207319925 },
         {  0.97316523498161, -1.94633046996323,  0.97316523498161 },
         {  1.00000000000000, -1.94561023566527,  0.94705070426118 },
     },
     {
         18900,
         {  0.38524531015142, -0.27682212062067, -0.09980181488805,
            0.09951486755646, -0.08934020156622, -0.00322369330199,
           -0.00110329090689,  0.03784509844682,  0.01683906213303,
           -0.01147039862572, -0.01941767987192 },
         {  1.00000000000000, -1.29708918404534,  0.90399339674203,
           -0.29613799017877, -0.42326645916207,  0.37934887402200,
           -0.37919795944938,  0.23410283284785, -0.03892971758879,
            0.00403009552351,  0.03640166626278 },
         {  0.96535326815829, -1.93070653631658,  0.96535326815829 },
         {  1.00000000000000, -1.92950577983524,  0.93190729279793 },
     },
     {
         16000,
         {  0.44915256608450, -0.14351757464547, -0.22784394429749,
           -0.01419140100551,  0.04078262797139, -0.12398163381748,
            0.04097565135648,  0.10478503600251, -0.01863887810927,
           -0.03193428438915,  0.00541907748707 },
         {  1.00000000000000, -0.62820619233671,  0.29661783706366,
           -0.37256372942400,  0.00213767857124, -0.42029820170918,
            0.22199650564824,  0.00613424350682,  0.06747620744683,
            0.05784820375801,  0.03222754072173 },
         {  0.96454515552826, -1.92909031105652,  0.96454515552826 },
         {  1.00000000000000, -1.92783286977036,  0.93034775234268 },
     },
     {
         12000,
         {  0.56619470757641, -0.75464456939302,  0.16242137742230,
            0.16744243493672, -0.18901604199609,  0.30931782841830,
           -0.27562961986224,  0.00647310677246,  0.08647503780351,
           -0.03788984554840, -0.00588215443421 },
         {  1.00000000000000, -1.04800335126349,  0.29156311971249,
           -0.26806001042947,  0.00819999645858,  0.45054734505008,
           -0.33032403314006,  0.06739368333110, -0.04784254229033,
            0.01639907836189,  0.01807364323573 },
         {  0.96009142950541, -1.92018285901082,  0.96009142950541 },
         {  1.00000000000000, -1.91858953033784,  0.92177618768381 },
     },
     {
         11025,
         {  0.58100494960553, -0.53174909058578, -0.14289799034253,
            0.17520704835522,  0.02377945217615,  0.15558449135573,
           -0.25344790059353,  0.01628462406333,  0.06920467763959,
           -0.03721611395801, -0.00749618797172 },
         {  1.00000000000000, -0.51035327095184, -0.31863563325245,
           -0.20256413484477,  0.14728154134330,  0.38952639978999,
           -0.23313271880868, -0.05246019024463, -0.02505961724053,
            0.02442357316099,  0.01818801111503 },
         {  0.95856916599601, -1.91713833199203,  0.95856916599601 },
         {  1.00000000000000, -1.91542108074780,  0.91885558323625 },
     },
     {
         8000,
         {  0.53648789255105, -0.42163034350696, -0.00275953611929,
            0.04267842219415, -0.10214864179676,  0.14590772289388,
           -0.02459864859345, -0.11202315195388, -0.04060034127000,
            0.04788665548180, -0.02217936801134 },
         {  1.00000000000000, -0.25049871956020, -0.43193942311114,
           -0.03424681017675, -0.04678328784242,  0.26408300200955,
            0.15113130533216, -0.17556493366449, -0.18823009262115,
            0.05477720428674,  0.04704409688120 },
         {  0.94597685600279, -1.89195371200558,  0.94597685600279 },
         {  1.00000000000000, -1.88903307939452,  0.89487434461664 },
     },
 };
 
 typedef struct ReplayGainContext {
     uint32_t histogram[HISTOGRAM_SLOTS];
     float peak;
     int yule_hist_i, butter_hist_i;
     const double *yule_coeff_a;
     const double *yule_coeff_b;
     const double *butter_coeff_a;
     const double *butter_coeff_b;
     float yule_hist_a[256];
     float yule_hist_b[256];
     float butter_hist_a[256];
     float butter_hist_b[256];
 } ReplayGainContext;
 
 static int query_formats(AVFilterContext *ctx)
 {
     AVFilterFormats *formats = NULL;
     AVFilterChannelLayouts *layout = NULL;
6aaac24d
     int i, ret;
c9660999
 
6aaac24d
     if ((ret = ff_add_format                 (&formats, AV_SAMPLE_FMT_FLT  )) < 0 ||
         (ret = ff_set_common_formats         (ctx     , formats            )) < 0 ||
         (ret = ff_add_channel_layout         (&layout , AV_CH_LAYOUT_STEREO)) < 0 ||
         (ret = ff_set_common_channel_layouts (ctx     , layout             )) < 0)
         return ret;
c9660999
 
     formats = NULL;
6aaac24d
     for (i = 0; i < FF_ARRAY_ELEMS(freqinfos); i++) {
         if ((ret = ff_add_format(&formats, freqinfos[i].sample_rate)) < 0)
             return ret;
     }
c9660999
 
6aaac24d
     return ff_set_common_samplerates(ctx, formats);
c9660999
 }
 
 static int config_input(AVFilterLink *inlink)
 {
     AVFilterContext *ctx = inlink->dst;
     ReplayGainContext *s = ctx->priv;
     int i;
 
     for (i = 0; i < FF_ARRAY_ELEMS(freqinfos); i++) {
         if (freqinfos[i].sample_rate == inlink->sample_rate)
             break;
     }
     av_assert0(i < FF_ARRAY_ELEMS(freqinfos));
 
     s->yule_coeff_a   = freqinfos[i].AYule;
     s->yule_coeff_b   = freqinfos[i].BYule;
     s->butter_coeff_a = freqinfos[i].AButter;
     s->butter_coeff_b = freqinfos[i].BButter;
 
     s->yule_hist_i   = 20;
     s->butter_hist_i = 4;
     inlink->partial_buf_size =
     inlink->min_samples =
     inlink->max_samples = inlink->sample_rate / 20;
 
     return 0;
 }
 
 /*
  * Update largest absolute sample value.
  */
 static void calc_stereo_peak(const float *samples, int nb_samples,
                              float *peak_p)
 {
     float peak = 0.0;
 
     while (nb_samples--) {
         if (samples[0] > peak)
             peak = samples[0];
         else if (-samples[0] > peak)
             peak = -samples[0];
 
         if (samples[1] > peak)
             peak = samples[1];
         else if (-samples[1] > peak)
             peak = -samples[1];
 
         samples += 2;
     }
 
     *peak_p = FFMAX(peak, *peak_p);
 }
 
 /*
  * Calculate stereo RMS level. Minimum value is about -100 dB for
  * digital silence. The 90 dB offset is to compensate for the
  * normalized float range and 3 dB is for stereo samples.
  */
 static double calc_stereo_rms(const float *samples, int nb_samples)
 {
     int count = nb_samples;
     double sum = 1e-16;
 
     while (count--) {
         sum += samples[0] * samples[0] + samples[1] * samples[1];
         samples += 2;
     }
 
     return 10 * log10 (sum / nb_samples) + 90.0 - 3.0;
 }
 
 /*
  * Optimized implementation of 2nd-order IIR stereo filter.
  */
 static void butter_filter_stereo_samples(ReplayGainContext *s,
                                          float *samples, int nb_samples)
 {
     const double *coeff_a = s->butter_coeff_a;
     const double *coeff_b = s->butter_coeff_b;
     float *hist_a   = s->butter_hist_a;
     float *hist_b   = s->butter_hist_b;
     double left, right;
     int i, j;
 
     i = s->butter_hist_i;
 
     // If filter history is very small magnitude, clear it completely
     // to prevent denormals from rattling around in there forever
     // (slowing us down).
 
     for (j = -4; j < 0; ++j)
         if (fabs(hist_a[i + j]) > 1e-10 || fabs(hist_b[i + j]) > 1e-10)
             break;
 
     if (!j) {
         memset(s->butter_hist_a, 0, sizeof(s->butter_hist_a));
         memset(s->butter_hist_b, 0, sizeof(s->butter_hist_b));
     }
 
     while (nb_samples--) {
         left   = (hist_b[i    ] = samples[0]) * coeff_b[0];
         right  = (hist_b[i + 1] = samples[1]) * coeff_b[0];
         left  += hist_b[i - 2] * coeff_b[1] - hist_a[i - 2] * coeff_a[1];
         right += hist_b[i - 1] * coeff_b[1] - hist_a[i - 1] * coeff_a[1];
         left  += hist_b[i - 4] * coeff_b[2] - hist_a[i - 4] * coeff_a[2];
         right += hist_b[i - 3] * coeff_b[2] - hist_a[i - 3] * coeff_a[2];
         samples[0] = hist_a[i    ] = (float) left;
         samples[1] = hist_a[i + 1] = (float) right;
         samples += 2;
 
         if ((i += 2) == 256) {
             memcpy(hist_a, hist_a + 252, sizeof(*hist_a) * 4);
             memcpy(hist_b, hist_b + 252, sizeof(*hist_b) * 4);
             i = 4;
         }
     }
 
     s->butter_hist_i = i;
 }
 
 /*
  * Optimized implementation of 10th-order IIR stereo filter.
  */
 static void yule_filter_stereo_samples(ReplayGainContext *s, const float *src,
                                        float *dst, int nb_samples)
 {
     const double *coeff_a = s->yule_coeff_a;
     const double *coeff_b = s->yule_coeff_b;
     float *hist_a   = s->yule_hist_a;
     float *hist_b   = s->yule_hist_b;
     double left, right;
     int i, j;
 
     i = s->yule_hist_i;
 
     // If filter history is very small magnitude, clear it completely to
     // prevent denormals from rattling around in there forever
     // (slowing us down).
 
     for (j = -20; j < 0; ++j)
         if (fabs(hist_a[i + j]) > 1e-10 || fabs(hist_b[i + j]) > 1e-10)
             break;
 
     if (!j) {
         memset(s->yule_hist_a, 0, sizeof(s->yule_hist_a));
         memset(s->yule_hist_b, 0, sizeof(s->yule_hist_b));
     }
 
     while (nb_samples--) {
         left   = (hist_b[i] = src[0]) * coeff_b[0];
         right  = (hist_b[i + 1] = src[1]) * coeff_b[0];
         left  += hist_b[i -  2] * coeff_b[ 1] - hist_a[i -  2] * coeff_a[1 ];
         right += hist_b[i -  1] * coeff_b[ 1] - hist_a[i -  1] * coeff_a[1 ];
         left  += hist_b[i -  4] * coeff_b[ 2] - hist_a[i -  4] * coeff_a[2 ];
         right += hist_b[i -  3] * coeff_b[ 2] - hist_a[i -  3] * coeff_a[2 ];
         left  += hist_b[i -  6] * coeff_b[ 3] - hist_a[i -  6] * coeff_a[3 ];
         right += hist_b[i -  5] * coeff_b[ 3] - hist_a[i -  5] * coeff_a[3 ];
         left  += hist_b[i -  8] * coeff_b[ 4] - hist_a[i -  8] * coeff_a[4 ];
         right += hist_b[i -  7] * coeff_b[ 4] - hist_a[i -  7] * coeff_a[4 ];
         left  += hist_b[i - 10] * coeff_b[ 5] - hist_a[i - 10] * coeff_a[5 ];
         right += hist_b[i -  9] * coeff_b[ 5] - hist_a[i -  9] * coeff_a[5 ];
         left  += hist_b[i - 12] * coeff_b[ 6] - hist_a[i - 12] * coeff_a[6 ];
         right += hist_b[i - 11] * coeff_b[ 6] - hist_a[i - 11] * coeff_a[6 ];
         left  += hist_b[i - 14] * coeff_b[ 7] - hist_a[i - 14] * coeff_a[7 ];
         right += hist_b[i - 13] * coeff_b[ 7] - hist_a[i - 13] * coeff_a[7 ];
         left  += hist_b[i - 16] * coeff_b[ 8] - hist_a[i - 16] * coeff_a[8 ];
         right += hist_b[i - 15] * coeff_b[ 8] - hist_a[i - 15] * coeff_a[8 ];
         left  += hist_b[i - 18] * coeff_b[ 9] - hist_a[i - 18] * coeff_a[9 ];
         right += hist_b[i - 17] * coeff_b[ 9] - hist_a[i - 17] * coeff_a[9 ];
         left  += hist_b[i - 20] * coeff_b[10] - hist_a[i - 20] * coeff_a[10];
         right += hist_b[i - 19] * coeff_b[10] - hist_a[i - 19] * coeff_a[10];
         dst[0] = hist_a[i    ] = (float)left;
         dst[1] = hist_a[i + 1] = (float)right;
         src += 2;
         dst += 2;
 
         if ((i += 2) == 256) {
             memcpy(hist_a, hist_a + 236, sizeof(*hist_a) * 20);
             memcpy(hist_b, hist_b + 236, sizeof(*hist_b) * 20);
             i = 20;
         }
     }
 
     s->yule_hist_i = i;
 }
 
 /*
  * Calculate the ReplayGain value from the specified loudness histogram;
  * clip to -24 / +64 dB.
  */
 static float calc_replaygain(uint32_t *histogram)
 {
     uint32_t loud_count = 0, total_windows = 0;
     float gain;
     int i;
 
     for (i = 0; i < HISTOGRAM_SLOTS; i++)
         total_windows += histogram [i];
 
     while (i--)
         if ((loud_count += histogram [i]) * 20 >= total_windows)
             break;
 
     gain = (float)(64.54 - i / 100.0);
 
     return av_clipf(gain, -24.0, 64.0);
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     ReplayGainContext *s = ctx->priv;
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     int64_t level;
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     AVFrame *out;
 
88cbd25b
     out = ff_get_audio_buffer(outlink, in->nb_samples);
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     if (!out) {
         av_frame_free(&in);
         return AVERROR(ENOMEM);
     }
 
     calc_stereo_peak((float *)in->data[0],
                               in->nb_samples, &s->peak);
     yule_filter_stereo_samples(s, (const float *)in->data[0],
                                         (float *)out->data[0],
                                                  out->nb_samples);
     butter_filter_stereo_samples(s, (float *)out->data[0],
                                              out->nb_samples);
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     level = lrint(floor(100 * calc_stereo_rms((float *)out->data[0],
                                                            out->nb_samples)));
     level = av_clip64(level, 0, HISTOGRAM_SLOTS - 1);
c9660999
 
     s->histogram[level]++;
 
     av_frame_free(&out);
     return ff_filter_frame(outlink, in);
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     ReplayGainContext *s = ctx->priv;
     float gain = calc_replaygain(s->histogram);
 
     av_log(ctx, AV_LOG_INFO, "track_gain = %+.2f dB\n", gain);
     av_log(ctx, AV_LOG_INFO, "track_peak = %.6f\n", s->peak);
 }
 
 static const AVFilterPad replaygain_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = filter_frame,
         .config_props = config_input,
     },
     { NULL }
 };
 
 static const AVFilterPad replaygain_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_AUDIO,
     },
     { NULL }
 };
 
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 AVFilter ff_af_replaygain = {
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     .name          = "replaygain",
     .description   = NULL_IF_CONFIG_SMALL("ReplayGain scanner."),
     .query_formats = query_formats,
     .uninit        = uninit,
     .priv_size     = sizeof(ReplayGainContext),
     .inputs        = replaygain_inputs,
     .outputs       = replaygain_outputs,
 };