text: /*
   * Copyright (c) 2009 Rob Sykes <robs@users.sourceforge.net>
   * Copyright (c) 2013 Paul B Mahol
   *
   * 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
   */
  
  #include <float.h>
  #include <math.h>
  
  #include "libavutil/opt.h"
  #include "audio.h"
  #include "avfilter.h"
  #include "internal.h"
  
  #define HISTOGRAM_SIZE                  8192
  #define HISTOGRAM_MAX                   (HISTOGRAM_SIZE-1)
  
  #define MEASURE_ALL                     UINT_MAX
  #define MEASURE_NONE                           0
  
  #define MEASURE_DC_OFFSET               (1 <<  0)
  #define MEASURE_MIN_LEVEL               (1 <<  1)
  #define MEASURE_MAX_LEVEL               (1 <<  2)
  #define MEASURE_MIN_DIFFERENCE          (1 <<  3)
  #define MEASURE_MAX_DIFFERENCE          (1 <<  4)
  #define MEASURE_MEAN_DIFFERENCE         (1 <<  5)
  #define MEASURE_RMS_DIFFERENCE          (1 <<  6)
  #define MEASURE_PEAK_LEVEL              (1 <<  7)
  #define MEASURE_RMS_LEVEL               (1 <<  8)
  #define MEASURE_RMS_PEAK                (1 <<  9)
  #define MEASURE_RMS_TROUGH              (1 << 10)
  #define MEASURE_CREST_FACTOR            (1 << 11)
  #define MEASURE_FLAT_FACTOR             (1 << 12)
  #define MEASURE_PEAK_COUNT              (1 << 13)
  #define MEASURE_BIT_DEPTH               (1 << 14)
  #define MEASURE_DYNAMIC_RANGE           (1 << 15)
  #define MEASURE_ZERO_CROSSINGS          (1 << 16)
  #define MEASURE_ZERO_CROSSINGS_RATE     (1 << 17)
  #define MEASURE_NUMBER_OF_SAMPLES       (1 << 18)
  #define MEASURE_NUMBER_OF_NANS          (1 << 19)
  #define MEASURE_NUMBER_OF_INFS          (1 << 20)
  #define MEASURE_NUMBER_OF_DENORMALS     (1 << 21)
  #define MEASURE_NOISE_FLOOR             (1 << 22)
  #define MEASURE_NOISE_FLOOR_COUNT       (1 << 23)
  #define MEASURE_ENTROPY                 (1 << 24)
  
  #define MEASURE_MINMAXPEAK              (MEASURE_MIN_LEVEL | MEASURE_MAX_LEVEL | MEASURE_PEAK_LEVEL)
  
  typedef struct ChannelStats {
      double last;
      double last_non_zero;
      double min_non_zero;
      double sigma_x, sigma_x2;
      double avg_sigma_x2, min_sigma_x2, max_sigma_x2;
      double min, max;
      double nmin, nmax;
      double min_run, max_run;
      double min_runs, max_runs;
      double min_diff, max_diff;
      double diff1_sum;
      double diff1_sum_x2;
      uint64_t mask, imask;
      uint64_t min_count, max_count;
      uint64_t noise_floor_count;
      uint64_t zero_runs;
      uint64_t nb_samples;
      uint64_t nb_nans;
      uint64_t nb_infs;
      uint64_t nb_denormals;
      double *win_samples;
      uint64_t histogram[HISTOGRAM_SIZE];
      uint64_t ehistogram[HISTOGRAM_SIZE];
      int win_pos;
      int max_index;
      double noise_floor;
      double entropy;
  } ChannelStats;
  
  typedef struct AudioStatsContext {
      const AVClass *class;
      ChannelStats *chstats;
      int nb_channels;
      uint64_t tc_samples;
      double time_constant;
      double mult;
      int metadata;
      int reset_count;
      int nb_frames;
      int maxbitdepth;
      int measure_perchannel;
      int measure_overall;
      int is_float;
      int is_double;
  } AudioStatsContext;
  
  #define OFFSET(x) offsetof(AudioStatsContext, x)
  #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
  
  static const AVOption astats_options[] = {
      { "length", "set the window length", OFFSET(time_constant), AV_OPT_TYPE_DOUBLE, {.dbl=.05}, 0, 10, FLAGS },
      { "metadata", "inject metadata in the filtergraph", OFFSET(metadata), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS },
      { "reset", "recalculate stats after this many frames", OFFSET(reset_count), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS },
      { "measure_perchannel", "only measure_perchannel these per-channel statistics", OFFSET(measure_perchannel), AV_OPT_TYPE_FLAGS, {.i64=MEASURE_ALL}, 0, UINT_MAX, FLAGS, "measure" },
        { "none"                      , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_NONE                }, 0, 0, FLAGS, "measure" },
        { "all"                       , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_ALL                 }, 0, 0, FLAGS, "measure" },
        { "DC_offset"                 , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_DC_OFFSET           }, 0, 0, FLAGS, "measure" },
        { "Min_level"                 , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_MIN_LEVEL           }, 0, 0, FLAGS, "measure" },
        { "Max_level"                 , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_MAX_LEVEL           }, 0, 0, FLAGS, "measure" },
        { "Min_difference"            , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_MIN_DIFFERENCE      }, 0, 0, FLAGS, "measure" },
        { "Max_difference"            , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_MAX_DIFFERENCE      }, 0, 0, FLAGS, "measure" },
        { "Mean_difference"           , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_MEAN_DIFFERENCE     }, 0, 0, FLAGS, "measure" },
        { "RMS_difference"            , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_RMS_DIFFERENCE      }, 0, 0, FLAGS, "measure" },
        { "Peak_level"                , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_PEAK_LEVEL          }, 0, 0, FLAGS, "measure" },
        { "RMS_level"                 , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_RMS_LEVEL           }, 0, 0, FLAGS, "measure" },
        { "RMS_peak"                  , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_RMS_PEAK            }, 0, 0, FLAGS, "measure" },
        { "RMS_trough"                , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_RMS_TROUGH          }, 0, 0, FLAGS, "measure" },
        { "Crest_factor"              , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_CREST_FACTOR        }, 0, 0, FLAGS, "measure" },
        { "Flat_factor"               , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_FLAT_FACTOR         }, 0, 0, FLAGS, "measure" },
        { "Peak_count"                , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_PEAK_COUNT          }, 0, 0, FLAGS, "measure" },
        { "Bit_depth"                 , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_BIT_DEPTH           }, 0, 0, FLAGS, "measure" },
        { "Dynamic_range"             , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_DYNAMIC_RANGE       }, 0, 0, FLAGS, "measure" },
        { "Zero_crossings"            , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_ZERO_CROSSINGS      }, 0, 0, FLAGS, "measure" },
        { "Zero_crossings_rate"       , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_ZERO_CROSSINGS_RATE }, 0, 0, FLAGS, "measure" },
        { "Noise_floor"               , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_NOISE_FLOOR         }, 0, 0, FLAGS, "measure" },
        { "Noise_floor_count"         , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_NOISE_FLOOR_COUNT   }, 0, 0, FLAGS, "measure" },
        { "Entropy"                   , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_ENTROPY             }, 0, 0, FLAGS, "measure" },
        { "Number_of_samples"         , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_NUMBER_OF_SAMPLES   }, 0, 0, FLAGS, "measure" },
        { "Number_of_NaNs"            , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_NUMBER_OF_NANS      }, 0, 0, FLAGS, "measure" },
        { "Number_of_Infs"            , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_NUMBER_OF_INFS      }, 0, 0, FLAGS, "measure" },
        { "Number_of_denormals"       , "", 0, AV_OPT_TYPE_CONST, {.i64=MEASURE_NUMBER_OF_DENORMALS }, 0, 0, FLAGS, "measure" },
      { "measure_overall", "only measure_perchannel these overall statistics", OFFSET(measure_overall), AV_OPT_TYPE_FLAGS, {.i64=MEASURE_ALL}, 0, UINT_MAX, FLAGS, "measure" },
      { NULL }
  };
  
  AVFILTER_DEFINE_CLASS(astats);
  
  static void reset_stats(AudioStatsContext *s)
  {
      int c;
  
      for (c = 0; c < s->nb_channels; c++) {
          ChannelStats *p = &s->chstats[c];
  
          p->min = p->nmin = p->min_sigma_x2 = DBL_MAX;
          p->max = p->nmax = p->max_sigma_x2 =-DBL_MAX;
          p->min_non_zero = DBL_MAX;
          p->min_diff = DBL_MAX;
          p->max_diff = 0;
          p->sigma_x = 0;
          p->sigma_x2 = 0;
          p->avg_sigma_x2 = 0;
          p->min_run = 0;
          p->max_run = 0;
          p->min_runs = 0;
          p->max_runs = 0;
          p->diff1_sum = 0;
          p->diff1_sum_x2 = 0;
          p->mask = 0;
          p->imask = 0xFFFFFFFFFFFFFFFF;
          p->min_count = 0;
          p->max_count = 0;
          p->zero_runs = 0;
          p->nb_samples = 0;
          p->nb_nans = 0;
          p->nb_infs = 0;
          p->nb_denormals = 0;
          p->last = NAN;
          p->noise_floor = NAN;
          p->noise_floor_count = 0;
          p->entropy = 0;
          p->win_pos = 0;
          memset(p->win_samples, 0, s->tc_samples * sizeof(*p->win_samples));
          memset(p->histogram, 0, sizeof(p->histogram));
          memset(p->ehistogram, 0, sizeof(p->ehistogram));
      }
  }
  
  static int config_output(AVFilterLink *outlink)
  {
      AudioStatsContext *s = outlink->src->priv;
  
      s->chstats = av_calloc(sizeof(*s->chstats), outlink->channels);
      if (!s->chstats)
          return AVERROR(ENOMEM);
  
      s->tc_samples = FFMAX(s->time_constant * outlink->sample_rate + .5, 1);
      s->nb_channels = outlink->channels;
  
      for (int i = 0; i < s->nb_channels; i++) {
          ChannelStats *p = &s->chstats[i];
  
          p->win_samples = av_calloc(s->tc_samples, sizeof(*p->win_samples));
          if (!p->win_samples)
              return AVERROR(ENOMEM);
      }
  
      s->mult = exp((-1 / s->time_constant / outlink->sample_rate));
      s->nb_frames = 0;
      s->maxbitdepth = av_get_bytes_per_sample(outlink->format) * 8;
      s->is_double = outlink->format == AV_SAMPLE_FMT_DBL  ||
                     outlink->format == AV_SAMPLE_FMT_DBLP;
  
      s->is_float = outlink->format == AV_SAMPLE_FMT_FLT  ||
                    outlink->format == AV_SAMPLE_FMT_FLTP;
  
      reset_stats(s);
  
      return 0;
  }
  
  static void bit_depth(AudioStatsContext *s, uint64_t mask, uint64_t imask, AVRational *depth)
  {
      unsigned result = s->maxbitdepth;
  
      mask = mask & (~imask);
  
      for (; result && !(mask & 1); --result, mask >>= 1);
  
      depth->den = result;
      depth->num = 0;
  
      for (; result; --result, mask >>= 1)
          if (mask & 1)
              depth->num++;
  }
  
  static double calc_entropy(AudioStatsContext *s, ChannelStats *p)
  {
      double entropy = 0.;
  
      for (int i = 0; i < HISTOGRAM_SIZE; i++) {
          double entry = p->ehistogram[i] / ((double)p->nb_samples);
  
          if (entry > 1e-8)
              entropy += entry * log2(entry);
      }
  
      return -entropy / log2(HISTOGRAM_SIZE);
  }
  
  static inline void update_minmax(AudioStatsContext *s, ChannelStats *p, double d)
  {
      if (d < p->min)
          p->min = d;
      if (d > p->max)
          p->max = d;
  }
  
  static inline void update_stat(AudioStatsContext *s, ChannelStats *p, double d, double nd, int64_t i)
  {
      double drop;
      int index;
  
      if (d < p->min) {
          p->min = d;
          p->nmin = nd;
          p->min_run = 1;
          p->min_runs = 0;
          p->min_count = 1;
      } else if (d == p->min) {
          p->min_count++;
          p->min_run = d == p->last ? p->min_run + 1 : 1;
      } else if (p->last == p->min) {
          p->min_runs += p->min_run * p->min_run;
      }
  
      if (d != 0 && FFABS(d) < p->min_non_zero)
          p->min_non_zero = FFABS(d);
  
      if (d > p->max) {
          p->max = d;
          p->nmax = nd;
          p->max_run = 1;
          p->max_runs = 0;
          p->max_count = 1;
      } else if (d == p->max) {
          p->max_count++;
          p->max_run = d == p->last ? p->max_run + 1 : 1;
      } else if (p->last == p->max) {
          p->max_runs += p->max_run * p->max_run;
      }
  
      if (d != 0) {
          p->zero_runs += FFSIGN(d) != FFSIGN(p->last_non_zero);
          p->last_non_zero = d;
      }
  
      p->sigma_x += nd;
      p->sigma_x2 += nd * nd;
      p->avg_sigma_x2 = p->avg_sigma_x2 * s->mult + (1.0 - s->mult) * nd * nd;
      if (!isnan(p->last)) {
          p->min_diff = FFMIN(p->min_diff, fabs(d - p->last));
          p->max_diff = FFMAX(p->max_diff, fabs(d - p->last));
          p->diff1_sum += fabs(d - p->last);
          p->diff1_sum_x2 += (d - p->last) * (d - p->last);
      }
      p->last = d;
      p->mask |= i;
      p->imask &= i;
  
      drop = p->win_samples[p->win_pos];
      p->win_samples[p->win_pos] = nd;
      index = av_clip(lrint(av_clipd(FFABS(nd), 0.0, 1.0) * HISTOGRAM_MAX), 0, HISTOGRAM_MAX);
      p->max_index = FFMAX(p->max_index, index);
      p->histogram[index]++;
      p->ehistogram[index]++;
      if (!isnan(p->noise_floor))
          p->histogram[av_clip(lrint(av_clipd(FFABS(drop), 0.0, 1.0) * HISTOGRAM_MAX), 0, HISTOGRAM_MAX)]--;
      p->win_pos++;
  
      while (p->histogram[p->max_index] == 0)
          p->max_index--;
      if (p->win_pos >= s->tc_samples || !isnan(p->noise_floor)) {
          double noise_floor = 1.;
  
          for (int i = p->max_index; i >= 0; i--) {
              if (p->histogram[i]) {
                  noise_floor = i / (double)HISTOGRAM_MAX;
                  break;
              }
          }
  
          if (isnan(p->noise_floor)) {
              p->noise_floor = noise_floor;
              p->noise_floor_count = 1;
          } else {
              if (noise_floor < p->noise_floor) {
                  p->noise_floor = noise_floor;
                  p->noise_floor_count = 1;
              } else if (noise_floor == p->noise_floor) {
                  p->noise_floor_count++;
              }
          }
      }
  
      if (p->win_pos >= s->tc_samples) {
          p->win_pos = 0;
      }
  
      if (p->nb_samples >= s->tc_samples) {
          p->max_sigma_x2 = FFMAX(p->max_sigma_x2, p->avg_sigma_x2);
          p->min_sigma_x2 = FFMIN(p->min_sigma_x2, p->avg_sigma_x2);
      }
      p->nb_samples++;
  }
  
  static inline void update_float_stat(AudioStatsContext *s, ChannelStats *p, float d)
  {
      int type = fpclassify(d);
  
      p->nb_nans      += type == FP_NAN;
      p->nb_infs      += type == FP_INFINITE;
      p->nb_denormals += type == FP_SUBNORMAL;
  }
  
  static inline void update_double_stat(AudioStatsContext *s, ChannelStats *p, double d)
  {
      int type = fpclassify(d);
  
      p->nb_nans      += type == FP_NAN;
      p->nb_infs      += type == FP_INFINITE;
      p->nb_denormals += type == FP_SUBNORMAL;
  }
  
  static void set_meta(AVDictionary **metadata, int chan, const char *key,
                       const char *fmt, double val)
  {
      uint8_t value[128];
      uint8_t key2[128];
  
      snprintf(value, sizeof(value), fmt, val);
      if (chan)
          snprintf(key2, sizeof(key2), "lavfi.astats.%d.%s", chan, key);
      else
          snprintf(key2, sizeof(key2), "lavfi.astats.%s", key);
      av_dict_set(metadata, key2, value, 0);
  }
  
  #define LINEAR_TO_DB(x) (log10(x) * 20)
  
  static void set_metadata(AudioStatsContext *s, AVDictionary **metadata)
  {
      uint64_t mask = 0, imask = 0xFFFFFFFFFFFFFFFF, min_count = 0, max_count = 0, nb_samples = 0, noise_floor_count = 0;
      uint64_t nb_nans = 0, nb_infs = 0, nb_denormals = 0;
      double min_runs = 0, max_runs = 0,
             min = DBL_MAX, max =-DBL_MAX, min_diff = DBL_MAX, max_diff = 0,
             nmin = DBL_MAX, nmax =-DBL_MAX,
             max_sigma_x = 0,
             diff1_sum = 0,
             diff1_sum_x2 = 0,
             sigma_x = 0,
             sigma_x2 = 0,
             noise_floor = 0,
             entropy = 0,
             min_sigma_x2 = DBL_MAX,
             max_sigma_x2 =-DBL_MAX;
      AVRational depth;
      int c;
  
      for (c = 0; c < s->nb_channels; c++) {
          ChannelStats *p = &s->chstats[c];
  
          if (p->nb_samples < s->tc_samples)
              p->min_sigma_x2 = p->max_sigma_x2 = p->sigma_x2 / p->nb_samples;
  
          min = FFMIN(min, p->min);
          max = FFMAX(max, p->max);
          nmin = FFMIN(nmin, p->nmin);
          nmax = FFMAX(nmax, p->nmax);
          min_diff = FFMIN(min_diff, p->min_diff);
          max_diff = FFMAX(max_diff, p->max_diff);
          diff1_sum += p->diff1_sum;
          diff1_sum_x2 += p->diff1_sum_x2;
          min_sigma_x2 = FFMIN(min_sigma_x2, p->min_sigma_x2);
          max_sigma_x2 = FFMAX(max_sigma_x2, p->max_sigma_x2);
          sigma_x += p->sigma_x;
          sigma_x2 += p->sigma_x2;
          noise_floor = FFMAX(noise_floor, p->noise_floor);
          noise_floor_count += p->noise_floor_count;
          p->entropy = calc_entropy(s, p);
          entropy += p->entropy;
          min_count += p->min_count;
          max_count += p->max_count;
          min_runs += p->min_runs;
          max_runs += p->max_runs;
          mask |= p->mask;
          imask &= p->imask;
          nb_samples += p->nb_samples;
          nb_nans += p->nb_nans;
          nb_infs += p->nb_infs;
          nb_denormals += p->nb_denormals;
          if (fabs(p->sigma_x) > fabs(max_sigma_x))
              max_sigma_x = p->sigma_x;
  
          if (s->measure_perchannel & MEASURE_DC_OFFSET)
              set_meta(metadata, c + 1, "DC_offset", "%f", p->sigma_x / p->nb_samples);
          if (s->measure_perchannel & MEASURE_MIN_LEVEL)
              set_meta(metadata, c + 1, "Min_level", "%f", p->min);
          if (s->measure_perchannel & MEASURE_MAX_LEVEL)
              set_meta(metadata, c + 1, "Max_level", "%f", p->max);
          if (s->measure_perchannel & MEASURE_MIN_DIFFERENCE)
              set_meta(metadata, c + 1, "Min_difference", "%f", p->min_diff);
          if (s->measure_perchannel & MEASURE_MAX_DIFFERENCE)
              set_meta(metadata, c + 1, "Max_difference", "%f", p->max_diff);
          if (s->measure_perchannel & MEASURE_MEAN_DIFFERENCE)
              set_meta(metadata, c + 1, "Mean_difference", "%f", p->diff1_sum / (p->nb_samples - 1));
          if (s->measure_perchannel & MEASURE_RMS_DIFFERENCE)
              set_meta(metadata, c + 1, "RMS_difference", "%f", sqrt(p->diff1_sum_x2 / (p->nb_samples - 1)));
          if (s->measure_perchannel & MEASURE_PEAK_LEVEL)
              set_meta(metadata, c + 1, "Peak_level", "%f", LINEAR_TO_DB(FFMAX(-p->nmin, p->nmax)));
          if (s->measure_perchannel & MEASURE_RMS_LEVEL)
              set_meta(metadata, c + 1, "RMS_level", "%f", LINEAR_TO_DB(sqrt(p->sigma_x2 / p->nb_samples)));
          if (s->measure_perchannel & MEASURE_RMS_PEAK)
              set_meta(metadata, c + 1, "RMS_peak", "%f", LINEAR_TO_DB(sqrt(p->max_sigma_x2)));
          if (s->measure_perchannel & MEASURE_RMS_TROUGH)
              set_meta(metadata, c + 1, "RMS_trough", "%f", LINEAR_TO_DB(sqrt(p->min_sigma_x2)));
          if (s->measure_perchannel & MEASURE_CREST_FACTOR)
              set_meta(metadata, c + 1, "Crest_factor", "%f", p->sigma_x2 ? FFMAX(-p->min, p->max) / sqrt(p->sigma_x2 / p->nb_samples) : 1);
          if (s->measure_perchannel & MEASURE_FLAT_FACTOR)
              set_meta(metadata, c + 1, "Flat_factor", "%f", LINEAR_TO_DB((p->min_runs + p->max_runs) / (p->min_count + p->max_count)));
          if (s->measure_perchannel & MEASURE_PEAK_COUNT)
              set_meta(metadata, c + 1, "Peak_count", "%f", (float)(p->min_count + p->max_count));
          if (s->measure_perchannel & MEASURE_NOISE_FLOOR)
              set_meta(metadata, c + 1, "Noise_floor", "%f", LINEAR_TO_DB(p->noise_floor));
          if (s->measure_perchannel & MEASURE_NOISE_FLOOR_COUNT)
              set_meta(metadata, c + 1, "Noise_floor_count", "%f", p->noise_floor_count);
          if (s->measure_perchannel & MEASURE_ENTROPY)
              set_meta(metadata, c + 1, "Entropy", "%f", p->entropy);
          if (s->measure_perchannel & MEASURE_BIT_DEPTH) {
              bit_depth(s, p->mask, p->imask, &depth);
              set_meta(metadata, c + 1, "Bit_depth", "%f", depth.num);
              set_meta(metadata, c + 1, "Bit_depth2", "%f", depth.den);
          }
          if (s->measure_perchannel & MEASURE_DYNAMIC_RANGE)
              set_meta(metadata, c + 1, "Dynamic_range", "%f", LINEAR_TO_DB(2 * FFMAX(FFABS(p->min), FFABS(p->max))/ p->min_non_zero));
          if (s->measure_perchannel & MEASURE_ZERO_CROSSINGS)
              set_meta(metadata, c + 1, "Zero_crossings", "%f", p->zero_runs);
          if (s->measure_perchannel & MEASURE_ZERO_CROSSINGS_RATE)
              set_meta(metadata, c + 1, "Zero_crossings_rate", "%f", p->zero_runs/(double)p->nb_samples);
          if ((s->is_float || s->is_double) && s->measure_perchannel & MEASURE_NUMBER_OF_NANS)
              set_meta(metadata, c + 1, "Number of NaNs", "%f", p->nb_nans);
          if ((s->is_float || s->is_double) && s->measure_perchannel & MEASURE_NUMBER_OF_INFS)
              set_meta(metadata, c + 1, "Number of Infs", "%f", p->nb_infs);
          if ((s->is_float || s->is_double) && s->measure_perchannel & MEASURE_NUMBER_OF_DENORMALS)
              set_meta(metadata, c + 1, "Number of denormals", "%f", p->nb_denormals);
      }
  
      if (s->measure_overall & MEASURE_DC_OFFSET)
          set_meta(metadata, 0, "Overall.DC_offset", "%f", max_sigma_x / (nb_samples / s->nb_channels));
      if (s->measure_overall & MEASURE_MIN_LEVEL)
          set_meta(metadata, 0, "Overall.Min_level", "%f", min);
      if (s->measure_overall & MEASURE_MAX_LEVEL)
          set_meta(metadata, 0, "Overall.Max_level", "%f", max);
      if (s->measure_overall & MEASURE_MIN_DIFFERENCE)
          set_meta(metadata, 0, "Overall.Min_difference", "%f", min_diff);
      if (s->measure_overall & MEASURE_MAX_DIFFERENCE)
          set_meta(metadata, 0, "Overall.Max_difference", "%f", max_diff);
      if (s->measure_overall & MEASURE_MEAN_DIFFERENCE)
          set_meta(metadata, 0, "Overall.Mean_difference", "%f", diff1_sum / (nb_samples - s->nb_channels));
      if (s->measure_overall & MEASURE_RMS_DIFFERENCE)
          set_meta(metadata, 0, "Overall.RMS_difference", "%f", sqrt(diff1_sum_x2 / (nb_samples - s->nb_channels)));
      if (s->measure_overall & MEASURE_PEAK_LEVEL)
          set_meta(metadata, 0, "Overall.Peak_level", "%f", LINEAR_TO_DB(FFMAX(-nmin, nmax)));
      if (s->measure_overall & MEASURE_RMS_LEVEL)
          set_meta(metadata, 0, "Overall.RMS_level", "%f", LINEAR_TO_DB(sqrt(sigma_x2 / nb_samples)));
      if (s->measure_overall & MEASURE_RMS_PEAK)
          set_meta(metadata, 0, "Overall.RMS_peak", "%f", LINEAR_TO_DB(sqrt(max_sigma_x2)));
      if (s->measure_overall & MEASURE_RMS_TROUGH)
          set_meta(metadata, 0, "Overall.RMS_trough", "%f", LINEAR_TO_DB(sqrt(min_sigma_x2)));
      if (s->measure_overall & MEASURE_FLAT_FACTOR)
          set_meta(metadata, 0, "Overall.Flat_factor", "%f", LINEAR_TO_DB((min_runs + max_runs) / (min_count + max_count)));
      if (s->measure_overall & MEASURE_PEAK_COUNT)
          set_meta(metadata, 0, "Overall.Peak_count", "%f", (float)(min_count + max_count) / (double)s->nb_channels);
      if (s->measure_overall & MEASURE_NOISE_FLOOR)
          set_meta(metadata, 0, "Overall.Noise_floor", "%f", LINEAR_TO_DB(noise_floor));
      if (s->measure_overall & MEASURE_NOISE_FLOOR_COUNT)
          set_meta(metadata, 0, "Overall.Noise_floor_count", "%f", noise_floor_count / (double)s->nb_channels);
      if (s->measure_overall & MEASURE_ENTROPY)
          set_meta(metadata, 0, "Overall.Entropy", "%f", entropy / (double)s->nb_channels);
      if (s->measure_overall & MEASURE_BIT_DEPTH) {
          bit_depth(s, mask, imask, &depth);
          set_meta(metadata, 0, "Overall.Bit_depth", "%f", depth.num);
          set_meta(metadata, 0, "Overall.Bit_depth2", "%f", depth.den);
      }
      if (s->measure_overall & MEASURE_NUMBER_OF_SAMPLES)
          set_meta(metadata, 0, "Overall.Number_of_samples", "%f", nb_samples / s->nb_channels);
      if ((s->is_float || s->is_double) && s->measure_overall & MEASURE_NUMBER_OF_NANS)
          set_meta(metadata, 0, "Number of NaNs", "%f", nb_nans / (float)s->nb_channels);
      if ((s->is_float || s->is_double) && s->measure_overall & MEASURE_NUMBER_OF_INFS)
          set_meta(metadata, 0, "Number of Infs", "%f", nb_infs / (float)s->nb_channels);
      if ((s->is_float || s->is_double) && s->measure_overall & MEASURE_NUMBER_OF_DENORMALS)
          set_meta(metadata, 0, "Number of denormals", "%f", nb_denormals / (float)s->nb_channels);
  }
  
  #define UPDATE_STATS_P(type, update_func, update_float, channel_func)           \
      for (int c = start; c < end; c++) {                                         \
          ChannelStats *p = &s->chstats[c];                                       \
          const type *src = (const type *)data[c];                                \
          const type * const srcend = src + samples;                              \
          for (; src < srcend; src++) {                                           \
              update_func;                                                        \
              update_float;                                                       \
          }                                                                       \
          channel_func;                                                           \
      }
  
  #define UPDATE_STATS_I(type, update_func, update_float, channel_func)           \
      for (int c = start; c < end; c++) {                                         \
          ChannelStats *p = &s->chstats[c];                                       \
          const type *src = (const type *)data[0];                                \
          const type * const srcend = src + samples * channels;                   \
          for (src += c; src < srcend; src += channels) {                         \
              update_func;                                                        \
              update_float;                                                       \
          }                                                                       \
          channel_func;                                                           \
      }
  
  #define UPDATE_STATS(planar, type, sample, normalizer_suffix, int_sample) \
      if ((s->measure_overall | s->measure_perchannel) & ~MEASURE_MINMAXPEAK) {                          \
          UPDATE_STATS_##planar(type, update_stat(s, p, sample, sample normalizer_suffix, int_sample), s->is_float ? update_float_stat(s, p, sample) : s->is_double ? update_double_stat(s, p, sample) : (void)NULL, ); \
      } else {                                                                                           \
          UPDATE_STATS_##planar(type, update_minmax(s, p, sample), , p->nmin = p->min normalizer_suffix; p->nmax = p->max normalizer_suffix;); \
      }
  
  static int filter_channel(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
  {
      AudioStatsContext *s = ctx->priv;
      AVFilterLink *inlink = ctx->inputs[0];
      AVFrame *buf = arg;
      const uint8_t * const * const data = (const uint8_t * const *)buf->extended_data;
      const int channels = s->nb_channels;
      const int samples = buf->nb_samples;
      const int start = (buf->channels * jobnr) / nb_jobs;
      const int end = (buf->channels * (jobnr+1)) / nb_jobs;
  
      switch (inlink->format) {
      case AV_SAMPLE_FMT_DBLP:
          UPDATE_STATS(P, double, *src, , llrint(*src * (UINT64_C(1) << 63)));
          break;
      case AV_SAMPLE_FMT_DBL:
          UPDATE_STATS(I, double, *src, , llrint(*src * (UINT64_C(1) << 63)));
          break;
      case AV_SAMPLE_FMT_FLTP:
          UPDATE_STATS(P, float, *src, , llrint(*src * (UINT64_C(1) << 31)));
          break;
      case AV_SAMPLE_FMT_FLT:
          UPDATE_STATS(I, float, *src, , llrint(*src * (UINT64_C(1) << 31)));
          break;
      case AV_SAMPLE_FMT_S64P:
          UPDATE_STATS(P, int64_t, *src, / (double)INT64_MAX, *src);
          break;
      case AV_SAMPLE_FMT_S64:
          UPDATE_STATS(I, int64_t, *src, / (double)INT64_MAX, *src);
          break;
      case AV_SAMPLE_FMT_S32P:
          UPDATE_STATS(P, int32_t, *src, / (double)INT32_MAX, *src);
          break;
      case AV_SAMPLE_FMT_S32:
          UPDATE_STATS(I, int32_t, *src, / (double)INT32_MAX, *src);
          break;
      case AV_SAMPLE_FMT_S16P:
          UPDATE_STATS(P, int16_t, *src, / (double)INT16_MAX, *src);
          break;
      case AV_SAMPLE_FMT_S16:
          UPDATE_STATS(I, int16_t, *src, / (double)INT16_MAX, *src);
          break;
      }
  
      return 0;
  }
  
  static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
  {
      AVFilterContext *ctx = inlink->dst;
      AudioStatsContext *s = ctx->priv;
      AVDictionary **metadata = &buf->metadata;
  
      if (s->reset_count > 0) {
          if (s->nb_frames >= s->reset_count) {
              reset_stats(s);
              s->nb_frames = 0;
          }
          s->nb_frames++;
      }
  
      ff_filter_execute(ctx, filter_channel, buf, NULL,
                        FFMIN(inlink->channels, ff_filter_get_nb_threads(ctx)));
  
      if (s->metadata)
          set_metadata(s, metadata);
  
      return ff_filter_frame(inlink->dst->outputs[0], buf);
  }
  
  static void print_stats(AVFilterContext *ctx)
  {
      AudioStatsContext *s = ctx->priv;
      uint64_t mask = 0, imask = 0xFFFFFFFFFFFFFFFF, min_count = 0, max_count = 0, nb_samples = 0, noise_floor_count = 0;
      uint64_t nb_nans = 0, nb_infs = 0, nb_denormals = 0;
      double min_runs = 0, max_runs = 0,
             min = DBL_MAX, max =-DBL_MAX, min_diff = DBL_MAX, max_diff = 0,
             nmin = DBL_MAX, nmax =-DBL_MAX,
             max_sigma_x = 0,
             diff1_sum_x2 = 0,
             diff1_sum = 0,
             sigma_x = 0,
             sigma_x2 = 0,
             noise_floor = 0,
             entropy = 0,
             min_sigma_x2 = DBL_MAX,
             max_sigma_x2 =-DBL_MAX;
      AVRational depth;
      int c;
  
      for (c = 0; c < s->nb_channels; c++) {
          ChannelStats *p = &s->chstats[c];
  
          if (p->nb_samples < s->tc_samples)
              p->min_sigma_x2 = p->max_sigma_x2 = p->sigma_x2 / p->nb_samples;
  
          min = FFMIN(min, p->min);
          max = FFMAX(max, p->max);
          nmin = FFMIN(nmin, p->nmin);
          nmax = FFMAX(nmax, p->nmax);
          min_diff = FFMIN(min_diff, p->min_diff);
          max_diff = FFMAX(max_diff, p->max_diff);
          diff1_sum_x2 += p->diff1_sum_x2;
          diff1_sum += p->diff1_sum;
          min_sigma_x2 = FFMIN(min_sigma_x2, p->min_sigma_x2);
          max_sigma_x2 = FFMAX(max_sigma_x2, p->max_sigma_x2);
          sigma_x += p->sigma_x;
          sigma_x2 += p->sigma_x2;
          noise_floor = FFMAX(noise_floor, p->noise_floor);
          p->entropy = calc_entropy(s, p);
          entropy += p->entropy;
          min_count += p->min_count;
          max_count += p->max_count;
          noise_floor_count += p->noise_floor_count;
          min_runs += p->min_runs;
          max_runs += p->max_runs;
          mask |= p->mask;
          imask &= p->imask;
          nb_samples += p->nb_samples;
          nb_nans += p->nb_nans;
          nb_infs += p->nb_infs;
          nb_denormals += p->nb_denormals;
          if (fabs(p->sigma_x) > fabs(max_sigma_x))
              max_sigma_x = p->sigma_x;
  
          if (s->measure_perchannel != MEASURE_NONE)
              av_log(ctx, AV_LOG_INFO, "Channel: %d\n", c + 1);
          if (s->measure_perchannel & MEASURE_DC_OFFSET)
              av_log(ctx, AV_LOG_INFO, "DC offset: %f\n", p->sigma_x / p->nb_samples);
          if (s->measure_perchannel & MEASURE_MIN_LEVEL)
              av_log(ctx, AV_LOG_INFO, "Min level: %f\n", p->min);
          if (s->measure_perchannel & MEASURE_MAX_LEVEL)
              av_log(ctx, AV_LOG_INFO, "Max level: %f\n", p->max);
          if (s->measure_perchannel & MEASURE_MIN_DIFFERENCE)
              av_log(ctx, AV_LOG_INFO, "Min difference: %f\n", p->min_diff);
          if (s->measure_perchannel & MEASURE_MAX_DIFFERENCE)
              av_log(ctx, AV_LOG_INFO, "Max difference: %f\n", p->max_diff);
          if (s->measure_perchannel & MEASURE_MEAN_DIFFERENCE)
              av_log(ctx, AV_LOG_INFO, "Mean difference: %f\n", p->diff1_sum / (p->nb_samples - 1));
          if (s->measure_perchannel & MEASURE_RMS_DIFFERENCE)
              av_log(ctx, AV_LOG_INFO, "RMS difference: %f\n", sqrt(p->diff1_sum_x2 / (p->nb_samples - 1)));
          if (s->measure_perchannel & MEASURE_PEAK_LEVEL)
              av_log(ctx, AV_LOG_INFO, "Peak level dB: %f\n", LINEAR_TO_DB(FFMAX(-p->nmin, p->nmax)));
          if (s->measure_perchannel & MEASURE_RMS_LEVEL)
              av_log(ctx, AV_LOG_INFO, "RMS level dB: %f\n", LINEAR_TO_DB(sqrt(p->sigma_x2 / p->nb_samples)));
          if (s->measure_perchannel & MEASURE_RMS_PEAK)
              av_log(ctx, AV_LOG_INFO, "RMS peak dB: %f\n", LINEAR_TO_DB(sqrt(p->max_sigma_x2)));
          if (s->measure_perchannel & MEASURE_RMS_TROUGH)
              if (p->min_sigma_x2 != 1)
                  av_log(ctx, AV_LOG_INFO, "RMS trough dB: %f\n",LINEAR_TO_DB(sqrt(p->min_sigma_x2)));
          if (s->measure_perchannel & MEASURE_CREST_FACTOR)
              av_log(ctx, AV_LOG_INFO, "Crest factor: %f\n", p->sigma_x2 ? FFMAX(-p->nmin, p->nmax) / sqrt(p->sigma_x2 / p->nb_samples) : 1);
          if (s->measure_perchannel & MEASURE_FLAT_FACTOR)
              av_log(ctx, AV_LOG_INFO, "Flat factor: %f\n", LINEAR_TO_DB((p->min_runs + p->max_runs) / (p->min_count + p->max_count)));
          if (s->measure_perchannel & MEASURE_PEAK_COUNT)
              av_log(ctx, AV_LOG_INFO, "Peak count: %"PRId64"\n", p->min_count + p->max_count);
          if (s->measure_perchannel & MEASURE_NOISE_FLOOR)
              av_log(ctx, AV_LOG_INFO, "Noise floor dB: %f\n", LINEAR_TO_DB(p->noise_floor));
          if (s->measure_perchannel & MEASURE_NOISE_FLOOR_COUNT)
              av_log(ctx, AV_LOG_INFO, "Noise floor count: %"PRId64"\n", p->noise_floor_count);
          if (s->measure_perchannel & MEASURE_ENTROPY)
              av_log(ctx, AV_LOG_INFO, "Entropy: %f\n", p->entropy);
          if (s->measure_perchannel & MEASURE_BIT_DEPTH) {
              bit_depth(s, p->mask, p->imask, &depth);
              av_log(ctx, AV_LOG_INFO, "Bit depth: %u/%u\n", depth.num, depth.den);
          }
          if (s->measure_perchannel & MEASURE_DYNAMIC_RANGE)
              av_log(ctx, AV_LOG_INFO, "Dynamic range: %f\n", LINEAR_TO_DB(2 * FFMAX(FFABS(p->min), FFABS(p->max))/ p->min_non_zero));
          if (s->measure_perchannel & MEASURE_ZERO_CROSSINGS)
              av_log(ctx, AV_LOG_INFO, "Zero crossings: %"PRId64"\n", p->zero_runs);
          if (s->measure_perchannel & MEASURE_ZERO_CROSSINGS_RATE)
              av_log(ctx, AV_LOG_INFO, "Zero crossings rate: %f\n", p->zero_runs/(double)p->nb_samples);
          if ((s->is_float || s->is_double) && s->measure_perchannel & MEASURE_NUMBER_OF_NANS)
              av_log(ctx, AV_LOG_INFO, "Number of NaNs: %"PRId64"\n", p->nb_nans);
          if ((s->is_float || s->is_double) && s->measure_perchannel & MEASURE_NUMBER_OF_INFS)
              av_log(ctx, AV_LOG_INFO, "Number of Infs: %"PRId64"\n", p->nb_infs);
          if ((s->is_float || s->is_double) && s->measure_perchannel & MEASURE_NUMBER_OF_DENORMALS)
              av_log(ctx, AV_LOG_INFO, "Number of denormals: %"PRId64"\n", p->nb_denormals);
      }
  
      if (s->measure_overall != MEASURE_NONE)
          av_log(ctx, AV_LOG_INFO, "Overall\n");
      if (s->measure_overall & MEASURE_DC_OFFSET)
          av_log(ctx, AV_LOG_INFO, "DC offset: %f\n", max_sigma_x / (nb_samples / s->nb_channels));
      if (s->measure_overall & MEASURE_MIN_LEVEL)
          av_log(ctx, AV_LOG_INFO, "Min level: %f\n", min);
      if (s->measure_overall & MEASURE_MAX_LEVEL)
          av_log(ctx, AV_LOG_INFO, "Max level: %f\n", max);
      if (s->measure_overall & MEASURE_MIN_DIFFERENCE)
          av_log(ctx, AV_LOG_INFO, "Min difference: %f\n", min_diff);
      if (s->measure_overall & MEASURE_MAX_DIFFERENCE)
          av_log(ctx, AV_LOG_INFO, "Max difference: %f\n", max_diff);
      if (s->measure_overall & MEASURE_MEAN_DIFFERENCE)
          av_log(ctx, AV_LOG_INFO, "Mean difference: %f\n", diff1_sum / (nb_samples - s->nb_channels));
      if (s->measure_overall & MEASURE_RMS_DIFFERENCE)
          av_log(ctx, AV_LOG_INFO, "RMS difference: %f\n", sqrt(diff1_sum_x2 / (nb_samples - s->nb_channels)));
      if (s->measure_overall & MEASURE_PEAK_LEVEL)
          av_log(ctx, AV_LOG_INFO, "Peak level dB: %f\n", LINEAR_TO_DB(FFMAX(-nmin, nmax)));
      if (s->measure_overall & MEASURE_RMS_LEVEL)
          av_log(ctx, AV_LOG_INFO, "RMS level dB: %f\n", LINEAR_TO_DB(sqrt(sigma_x2 / nb_samples)));
      if (s->measure_overall & MEASURE_RMS_PEAK)
          av_log(ctx, AV_LOG_INFO, "RMS peak dB: %f\n", LINEAR_TO_DB(sqrt(max_sigma_x2)));
      if (s->measure_overall & MEASURE_RMS_TROUGH)
          if (min_sigma_x2 != 1)
              av_log(ctx, AV_LOG_INFO, "RMS trough dB: %f\n", LINEAR_TO_DB(sqrt(min_sigma_x2)));
      if (s->measure_overall & MEASURE_FLAT_FACTOR)
          av_log(ctx, AV_LOG_INFO, "Flat factor: %f\n", LINEAR_TO_DB((min_runs + max_runs) / (min_count + max_count)));
      if (s->measure_overall & MEASURE_PEAK_COUNT)
          av_log(ctx, AV_LOG_INFO, "Peak count: %f\n", (min_count + max_count) / (double)s->nb_channels);
      if (s->measure_overall & MEASURE_NOISE_FLOOR)
          av_log(ctx, AV_LOG_INFO, "Noise floor dB: %f\n", LINEAR_TO_DB(noise_floor));
      if (s->measure_overall & MEASURE_NOISE_FLOOR_COUNT)
          av_log(ctx, AV_LOG_INFO, "Noise floor count: %f\n", noise_floor_count / (double)s->nb_channels);
      if (s->measure_overall & MEASURE_ENTROPY)
          av_log(ctx, AV_LOG_INFO, "Entropy: %f\n", entropy / (double)s->nb_channels);
      if (s->measure_overall & MEASURE_BIT_DEPTH) {
          bit_depth(s, mask, imask, &depth);
          av_log(ctx, AV_LOG_INFO, "Bit depth: %u/%u\n", depth.num, depth.den);
      }
      if (s->measure_overall & MEASURE_NUMBER_OF_SAMPLES)
          av_log(ctx, AV_LOG_INFO, "Number of samples: %"PRId64"\n", nb_samples / s->nb_channels);
      if ((s->is_float || s->is_double) && s->measure_overall & MEASURE_NUMBER_OF_NANS)
          av_log(ctx, AV_LOG_INFO, "Number of NaNs: %f\n", nb_nans / (float)s->nb_channels);
      if ((s->is_float || s->is_double) && s->measure_overall & MEASURE_NUMBER_OF_INFS)
          av_log(ctx, AV_LOG_INFO, "Number of Infs: %f\n", nb_infs / (float)s->nb_channels);
      if ((s->is_float || s->is_double) && s->measure_overall & MEASURE_NUMBER_OF_DENORMALS)
          av_log(ctx, AV_LOG_INFO, "Number of denormals: %f\n", nb_denormals / (float)s->nb_channels);
  }
  
  static av_cold void uninit(AVFilterContext *ctx)
  {
      AudioStatsContext *s = ctx->priv;
  
      if (s->nb_channels)
          print_stats(ctx);
      if (s->chstats) {
          for (int i = 0; i < s->nb_channels; i++) {
              ChannelStats *p = &s->chstats[i];
  
              av_freep(&p->win_samples);
          }
      }
      av_freep(&s->chstats);
  }
  
  static const AVFilterPad astats_inputs[] = {
      {
          .name         = "default",
          .type         = AVMEDIA_TYPE_AUDIO,
          .filter_frame = filter_frame,
      },
  };
  
  static const AVFilterPad astats_outputs[] = {
      {
          .name         = "default",
          .type         = AVMEDIA_TYPE_AUDIO,
          .config_props = config_output,
      },
  };
  
  const AVFilter ff_af_astats = {
      .name          = "astats",
      .description   = NULL_IF_CONFIG_SMALL("Show time domain statistics about audio frames."),
      .priv_size     = sizeof(AudioStatsContext),
      .priv_class    = &astats_class,
      .uninit        = uninit,
      FILTER_INPUTS(astats_inputs),
      FILTER_OUTPUTS(astats_outputs),
      FILTER_SAMPLEFMTS(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S16P,
                        AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S32P,
                        AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_S64P,
                        AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_FLTP,
                        AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_DBLP),
      .flags         = AVFILTER_FLAG_SLICE_THREADS,
  };
  