/*

* 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 {

} 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 {

} ReplayGainContext;

static int query_formats(AVFilterContext *ctx)

{

AVFilterFormats *formats = NULL;

AVFilterChannelLayouts *layout = NULL;

int i, ret;

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;

formats = NULL;

for (i = 0; i < FF_ARRAY_ELEMS(freqinfos); i++) {

if ((ret = ff_add_format(&formats, freqinfos[i].sample_rate)) < 0)

return ret;

}

return ff_set_common_samplerates(ctx, formats);

}

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;

uint32_t level;

AVFrame *out;

out = ff_get_audio_buffer(outlink, in->nb_samples);

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);

level = (uint32_t)floor(100 * calc_stereo_rms((float *)out->data[0],

out->nb_samples));

level = av_clip(level, 0, HISTOGRAM_SLOTS - 1);

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 }

};

AVFilter ff_af_replaygain = {

.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,

};