/*
  * Copyright (c) 2015 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 "libavcodec/avfft.h"
 #include "libavutil/audio_fifo.h"
 #include "libavutil/avassert.h"
 #include "libavutil/avstring.h"
 #include "libavutil/channel_layout.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"
 #include "audio.h"
 #include "video.h"
 #include "avfilter.h"
 #include "internal.h"

 #include "window_func.h"

 
 enum DisplayMode    { LINE, BAR, DOT, NB_MODES };

 enum ChannelMode    { COMBINED, SEPARATE, NB_CMODES };

 enum FrequencyScale { FS_LINEAR, FS_LOG, FS_RLOG, NB_FSCALES };
 enum AmplitudeScale { AS_LINEAR, AS_SQRT, AS_CBRT, AS_LOG, NB_ASCALES };
 
 typedef struct ShowFreqsContext {
     const AVClass *class;
     int w, h;
     int mode;

     int cmode;

     int fft_bits;
     int ascale, fscale;
     int avg;
     int win_func;
     FFTContext *fft;
     FFTComplex **fft_data;
     float **avg_data;
     float *window_func_lut;
     float overlap;

     float minamp;

     int hop_size;

     int nb_channels;
     int nb_freq;
     int win_size;
     float scale;
     char *colors;
     AVAudioFifo *fifo;
     int64_t pts;
 } ShowFreqsContext;
 
 #define OFFSET(x) offsetof(ShowFreqsContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
 static const AVOption showfreqs_options[] = {
     { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "1024x512"}, 0, 0, FLAGS },
     { "s",    "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "1024x512"}, 0, 0, FLAGS },
     { "mode", "set display mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=BAR}, 0, NB_MODES-1, FLAGS, "mode" },
         { "line", "show lines",  0, AV_OPT_TYPE_CONST, {.i64=LINE},   0, 0, FLAGS, "mode" },
         { "bar",  "show bars",   0, AV_OPT_TYPE_CONST, {.i64=BAR},    0, 0, FLAGS, "mode" },
         { "dot",  "show dots",   0, AV_OPT_TYPE_CONST, {.i64=DOT},    0, 0, FLAGS, "mode" },
     { "ascale", "set amplitude scale", OFFSET(ascale), AV_OPT_TYPE_INT, {.i64=AS_LOG}, 0, NB_ASCALES-1, FLAGS, "ascale" },
         { "lin",  "linear",      0, AV_OPT_TYPE_CONST, {.i64=AS_LINEAR}, 0, 0, FLAGS, "ascale" },
         { "sqrt", "square root", 0, AV_OPT_TYPE_CONST, {.i64=AS_SQRT},   0, 0, FLAGS, "ascale" },
         { "cbrt", "cubic root",  0, AV_OPT_TYPE_CONST, {.i64=AS_CBRT},   0, 0, FLAGS, "ascale" },
         { "log",  "logarithmic", 0, AV_OPT_TYPE_CONST, {.i64=AS_LOG},    0, 0, FLAGS, "ascale" },
     { "fscale", "set frequency scale", OFFSET(fscale), AV_OPT_TYPE_INT, {.i64=FS_LINEAR}, 0, NB_FSCALES-1, FLAGS, "fscale" },
         { "lin",  "linear",              0, AV_OPT_TYPE_CONST, {.i64=FS_LINEAR}, 0, 0, FLAGS, "fscale" },
         { "log",  "logarithmic",         0, AV_OPT_TYPE_CONST, {.i64=FS_LOG},    0, 0, FLAGS, "fscale" },
         { "rlog", "reverse logarithmic", 0, AV_OPT_TYPE_CONST, {.i64=FS_RLOG},   0, 0, FLAGS, "fscale" },
     { "win_size", "set window size", OFFSET(fft_bits), AV_OPT_TYPE_INT, {.i64=11}, 4, 16, FLAGS, "fft" },
         { "w16",    0, 0, AV_OPT_TYPE_CONST, {.i64=4},  0, 0, FLAGS, "fft" },
         { "w32",    0, 0, AV_OPT_TYPE_CONST, {.i64=5},  0, 0, FLAGS, "fft" },
         { "w64",    0, 0, AV_OPT_TYPE_CONST, {.i64=6},  0, 0, FLAGS, "fft" },
         { "w128",   0, 0, AV_OPT_TYPE_CONST, {.i64=7},  0, 0, FLAGS, "fft" },
         { "w256",   0, 0, AV_OPT_TYPE_CONST, {.i64=8},  0, 0, FLAGS, "fft" },
         { "w512",   0, 0, AV_OPT_TYPE_CONST, {.i64=9},  0, 0, FLAGS, "fft" },
         { "w1024",  0, 0, AV_OPT_TYPE_CONST, {.i64=10}, 0, 0, FLAGS, "fft" },
         { "w2048",  0, 0, AV_OPT_TYPE_CONST, {.i64=11}, 0, 0, FLAGS, "fft" },
         { "w4096",  0, 0, AV_OPT_TYPE_CONST, {.i64=12}, 0, 0, FLAGS, "fft" },
         { "w8192",  0, 0, AV_OPT_TYPE_CONST, {.i64=13}, 0, 0, FLAGS, "fft" },
         { "w16384", 0, 0, AV_OPT_TYPE_CONST, {.i64=14}, 0, 0, FLAGS, "fft" },
         { "w32768", 0, 0, AV_OPT_TYPE_CONST, {.i64=15}, 0, 0, FLAGS, "fft" },
         { "w65536", 0, 0, AV_OPT_TYPE_CONST, {.i64=16}, 0, 0, FLAGS, "fft" },
     { "win_func", "set window function", OFFSET(win_func), AV_OPT_TYPE_INT, {.i64=WFUNC_HANNING}, 0, NB_WFUNC-1, FLAGS, "win_func" },
         { "rect",     "Rectangular",      0, AV_OPT_TYPE_CONST, {.i64=WFUNC_RECT},     0, 0, FLAGS, "win_func" },
         { "bartlett", "Bartlett",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BARTLETT}, 0, 0, FLAGS, "win_func" },
         { "hanning",  "Hanning",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING},  0, 0, FLAGS, "win_func" },
         { "hamming",  "Hamming",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HAMMING},  0, 0, FLAGS, "win_func" },
         { "blackman", "Blackman",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BLACKMAN}, 0, 0, FLAGS, "win_func" },
         { "welch",    "Welch",            0, AV_OPT_TYPE_CONST, {.i64=WFUNC_WELCH},    0, 0, FLAGS, "win_func" },
         { "flattop",  "Flat-top",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_FLATTOP},  0, 0, FLAGS, "win_func" },
         { "bharris",  "Blackman-Harris",  0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BHARRIS},  0, 0, FLAGS, "win_func" },
         { "bnuttall", "Blackman-Nuttall", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BNUTTALL}, 0, 0, FLAGS, "win_func" },
         { "bhann",    "Bartlett-Hann",    0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BHANN},    0, 0, FLAGS, "win_func" },
         { "sine",     "Sine",             0, AV_OPT_TYPE_CONST, {.i64=WFUNC_SINE},     0, 0, FLAGS, "win_func" },
         { "nuttall",  "Nuttall",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_NUTTALL},  0, 0, FLAGS, "win_func" },

         { "lanczos",  "Lanczos",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_LANCZOS},  0, 0, FLAGS, "win_func" },
         { "gauss",    "Gauss",            0, AV_OPT_TYPE_CONST, {.i64=WFUNC_GAUSS},    0, 0, FLAGS, "win_func" },

         { "tukey",    "Tukey",            0, AV_OPT_TYPE_CONST, {.i64=WFUNC_TUKEY},    0, 0, FLAGS, "win_func" },

         { "dolph",    "Dolph-Chebyshev",  0, AV_OPT_TYPE_CONST, {.i64=WFUNC_DOLPH},    0, 0, FLAGS, "win_func" },

         { "cauchy",   "Cauchy",           0, AV_OPT_TYPE_CONST, {.i64=WFUNC_CAUCHY},   0, 0, FLAGS, "win_func" },
         { "parzen",   "Parzen",           0, AV_OPT_TYPE_CONST, {.i64=WFUNC_PARZEN},   0, 0, FLAGS, "win_func" },
         { "poisson",  "Poisson",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_POISSON},  0, 0, FLAGS, "win_func" },

     { "overlap",  "set window overlap", OFFSET(overlap), AV_OPT_TYPE_FLOAT, {.dbl=1.}, 0., 1., FLAGS },
     { "averaging", "set time averaging", OFFSET(avg), AV_OPT_TYPE_INT, {.i64=1}, 0, INT32_MAX, FLAGS },
     { "colors", "set channels colors", OFFSET(colors), AV_OPT_TYPE_STRING, {.str = "red|green|blue|yellow|orange|lime|pink|magenta|brown" }, 0, 0, FLAGS },

     { "cmode", "set channel mode", OFFSET(cmode), AV_OPT_TYPE_INT, {.i64=COMBINED}, 0, NB_CMODES-1, FLAGS, "cmode" },
         { "combined", "show all channels in same window",  0, AV_OPT_TYPE_CONST, {.i64=COMBINED}, 0, 0, FLAGS, "cmode" },
         { "separate", "show each channel in own window",   0, AV_OPT_TYPE_CONST, {.i64=SEPARATE}, 0, 0, FLAGS, "cmode" },

     { "minamp",  "set minimum amplitude", OFFSET(minamp), AV_OPT_TYPE_FLOAT, {.dbl=1e-6}, FLT_MIN, 1e-6, FLAGS },

     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(showfreqs);
 
 static int query_formats(AVFilterContext *ctx)
 {
     AVFilterFormats *formats = NULL;
     AVFilterChannelLayouts *layouts = NULL;
     AVFilterLink *inlink = ctx->inputs[0];
     AVFilterLink *outlink = ctx->outputs[0];
     static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_NONE };
     static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_RGBA, AV_PIX_FMT_NONE };

     int ret;

 
     /* set input audio formats */
     formats = ff_make_format_list(sample_fmts);

     if ((ret = ff_formats_ref(formats, &inlink->out_formats)) < 0)
         return ret;

 
     layouts = ff_all_channel_layouts();

     if ((ret = ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts)) < 0)
         return ret;

 
     formats = ff_all_samplerates();

     if ((ret = ff_formats_ref(formats, &inlink->out_samplerates)) < 0)
         return ret;

 
     /* set output video format */
     formats = ff_make_format_list(pix_fmts);

     if ((ret = ff_formats_ref(formats, &outlink->in_formats)) < 0)
         return ret;

 
     return 0;
 }
 

 static av_cold int init(AVFilterContext *ctx)
 {
     ShowFreqsContext *s = ctx->priv;
 
     s->pts = AV_NOPTS_VALUE;
 
     return 0;
 }
 

 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     AVFilterLink *inlink = ctx->inputs[0];
     ShowFreqsContext *s = ctx->priv;
     float overlap;
     int i;
 
     s->nb_freq = 1 << (s->fft_bits - 1);
     s->win_size = s->nb_freq << 1;
     av_audio_fifo_free(s->fifo);
     av_fft_end(s->fft);
     s->fft = av_fft_init(s->fft_bits, 0);
     if (!s->fft) {
         av_log(ctx, AV_LOG_ERROR, "Unable to create FFT context. "
                "The window size might be too high.\n");
         return AVERROR(ENOMEM);
     }
 
     /* FFT buffers: x2 for each (display) channel buffer.
      * Note: we use free and malloc instead of a realloc-like function to
      * make sure the buffer is aligned in memory for the FFT functions. */
     for (i = 0; i < s->nb_channels; i++) {
         av_freep(&s->fft_data[i]);
         av_freep(&s->avg_data[i]);
     }
     av_freep(&s->fft_data);
     av_freep(&s->avg_data);
     s->nb_channels = inlink->channels;
 
     s->fft_data = av_calloc(s->nb_channels, sizeof(*s->fft_data));
     if (!s->fft_data)
         return AVERROR(ENOMEM);
     s->avg_data = av_calloc(s->nb_channels, sizeof(*s->avg_data));
     if (!s->fft_data)
         return AVERROR(ENOMEM);
     for (i = 0; i < s->nb_channels; i++) {
         s->fft_data[i] = av_calloc(s->win_size, sizeof(**s->fft_data));
         s->avg_data[i] = av_calloc(s->nb_freq, sizeof(**s->avg_data));
         if (!s->fft_data[i] || !s->avg_data[i])
             return AVERROR(ENOMEM);
     }
 
     /* pre-calc windowing function */
     s->window_func_lut = av_realloc_f(s->window_func_lut, s->win_size,
                                       sizeof(*s->window_func_lut));
     if (!s->window_func_lut)
         return AVERROR(ENOMEM);

     generate_window_func(s->window_func_lut, s->win_size, s->win_func, &overlap);

     if (s->overlap == 1.)
         s->overlap = overlap;

     s->hop_size = (1. - s->overlap) * s->win_size;
     if (s->hop_size < 1) {

         av_log(ctx, AV_LOG_ERROR, "overlap %f too big\n", s->overlap);
         return AVERROR(EINVAL);
     }
 
     for (s->scale = 0, i = 0; i < s->win_size; i++) {
         s->scale += s->window_func_lut[i] * s->window_func_lut[i];
     }
 
     outlink->frame_rate = av_make_q(inlink->sample_rate, s->win_size * (1.-s->overlap));
     outlink->sample_aspect_ratio = (AVRational){1,1};
     outlink->w = s->w;
     outlink->h = s->h;
 
     s->fifo = av_audio_fifo_alloc(inlink->format, inlink->channels, s->win_size);
     if (!s->fifo)
         return AVERROR(ENOMEM);
     return 0;
 }
 
 static inline void draw_dot(AVFrame *out, int x, int y, uint8_t fg[4])
 {
 
     uint32_t color = AV_RL32(out->data[0] + y * out->linesize[0] + x * 4);
 
     if ((color & 0xffffff) != 0)
         AV_WL32(out->data[0] + y * out->linesize[0] + x * 4, AV_RL32(fg) | color);
     else
         AV_WL32(out->data[0] + y * out->linesize[0] + x * 4, AV_RL32(fg));
 }
 
 static int get_sx(ShowFreqsContext *s, int f)
 {
     switch (s->fscale) {
     case FS_LINEAR:
         return (s->w/(float)s->nb_freq)*f;
     case FS_LOG:
         return s->w-pow(s->w, (s->nb_freq-f-1)/(s->nb_freq-1.));
     case FS_RLOG:
         return pow(s->w, f/(s->nb_freq-1.));
     }
 
     return 0;
 }
 
 static float get_bsize(ShowFreqsContext *s, int f)
 {
     switch (s->fscale) {
     case FS_LINEAR:
         return s->w/(float)s->nb_freq;
     case FS_LOG:
         return pow(s->w, (s->nb_freq-f-1)/(s->nb_freq-1.))-
                pow(s->w, (s->nb_freq-f-2)/(s->nb_freq-1.));
     case FS_RLOG:
         return pow(s->w, (f+1)/(s->nb_freq-1.))-
                pow(s->w,  f   /(s->nb_freq-1.));
     }
 
     return 1.;
 }
 
 static inline void plot_freq(ShowFreqsContext *s, int ch,
                              double a, int f, uint8_t fg[4], int *prev_y,
                              AVFrame *out, AVFilterLink *outlink)
 {
     const int w = s->w;

     const float min = s->minamp;

     const float avg = s->avg_data[ch][f];
     const float bsize = get_bsize(s, f);
     const int sx = get_sx(s, f);

     int end = outlink->h;

     int x, y, i;
 
     switch(s->ascale) {
     case AS_SQRT:
         a = 1.0 - sqrt(a);
         break;
     case AS_CBRT:
         a = 1.0 - cbrt(a);
         break;
     case AS_LOG:

         a = log(av_clipd(a, min, 1)) / log(min);

         break;
     case AS_LINEAR:
         a = 1.0 - a;
         break;
     }

 
     switch (s->cmode) {
     case COMBINED:
         y = a * outlink->h - 1;
         break;
     case SEPARATE:
         end = (outlink->h / s->nb_channels) * (ch + 1);
         y = (outlink->h / s->nb_channels) * ch + a * (outlink->h / s->nb_channels) - 1;
         break;

     default:
         av_assert0(0);

     }

     if (y < 0)
         return;
 
     switch (s->avg) {
     case 0:

         y = s->avg_data[ch][f] = !outlink->frame_count_in ? y : FFMIN(avg, y);

         break;
     case 1:
         break;
     default:

         s->avg_data[ch][f] = avg + y * (y - avg) / (FFMIN(outlink->frame_count_in + 1, s->avg) * y);

         y = s->avg_data[ch][f];
         break;
     }
 
     switch(s->mode) {
     case LINE:
         if (*prev_y == -1) {
             *prev_y = y;
         }
         if (y <= *prev_y) {
             for (x = sx + 1; x < sx + bsize && x < w; x++)
                 draw_dot(out, x, y, fg);
             for (i = y; i <= *prev_y; i++)
                 draw_dot(out, sx, i, fg);
         } else {
             for (i = *prev_y; i <= y; i++)
                 draw_dot(out, sx, i, fg);
             for (x = sx + 1; x < sx + bsize && x < w; x++)
                 draw_dot(out, x, i - 1, fg);
         }
         *prev_y = y;
         break;
     case BAR:
         for (x = sx; x < sx + bsize && x < w; x++)

             for (i = y; i < end; i++)

                 draw_dot(out, x, i, fg);
         break;
     case DOT:
         for (x = sx; x < sx + bsize && x < w; x++)
             draw_dot(out, x, y, fg);
         break;
     }
 }
 
 static int plot_freqs(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     ShowFreqsContext *s = ctx->priv;
     const int win_size = s->win_size;
     char *colors, *color, *saveptr = NULL;
     AVFrame *out;
     int ch, n;
 
     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     if (!out)
         return AVERROR(ENOMEM);
 
     for (n = 0; n < outlink->h; n++)
         memset(out->data[0] + out->linesize[0] * n, 0, outlink->w * 4);
 
     /* fill FFT input with the number of samples available */
     for (ch = 0; ch < s->nb_channels; ch++) {
         const float *p = (float *)in->extended_data[ch];
 
         for (n = 0; n < in->nb_samples; n++) {
             s->fft_data[ch][n].re = p[n] * s->window_func_lut[n];
             s->fft_data[ch][n].im = 0;
         }
         for (; n < win_size; n++) {
             s->fft_data[ch][n].re = 0;
             s->fft_data[ch][n].im = 0;
         }
     }
 
     /* run FFT on each samples set */
     for (ch = 0; ch < s->nb_channels; ch++) {
         av_fft_permute(s->fft, s->fft_data[ch]);
         av_fft_calc(s->fft, s->fft_data[ch]);
     }
 
 #define RE(x, ch) s->fft_data[ch][x].re
 #define IM(x, ch) s->fft_data[ch][x].im
 #define M(a, b) (sqrt((a) * (a) + (b) * (b)))
 
     colors = av_strdup(s->colors);

     if (!colors) {
         av_frame_free(&out);

         return AVERROR(ENOMEM);

     }

 
     for (ch = 0; ch < s->nb_channels; ch++) {
         uint8_t fg[4] = { 0xff, 0xff, 0xff, 0xff };
         int prev_y = -1, f;
         double a;
 
         color = av_strtok(ch == 0 ? colors : NULL, " |", &saveptr);
         if (color)
             av_parse_color(fg, color, -1, ctx);
 
         a = av_clipd(M(RE(0, ch), 0) / s->scale, 0, 1);
         plot_freq(s, ch, a, 0, fg, &prev_y, out, outlink);
 
         for (f = 1; f < s->nb_freq; f++) {
             a = av_clipd(M(RE(f, ch), IM(f, ch)) / s->scale, 0, 1);
 
             plot_freq(s, ch, a, f, fg, &prev_y, out, outlink);
         }
     }
 
     av_free(colors);
     out->pts = in->pts;

     out->sample_aspect_ratio = (AVRational){1,1};

     return ff_filter_frame(outlink, out);
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     ShowFreqsContext *s = ctx->priv;
     AVFrame *fin = NULL;

     int consumed = 0;

     int ret = 0;

     if (s->pts == AV_NOPTS_VALUE)
         s->pts = in->pts - av_audio_fifo_size(s->fifo);
 

     av_audio_fifo_write(s->fifo, (void **)in->extended_data, in->nb_samples);
     while (av_audio_fifo_size(s->fifo) >= s->win_size) {
         fin = ff_get_audio_buffer(inlink, s->win_size);
         if (!fin) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }
 

         fin->pts = s->pts + consumed;
         consumed += s->hop_size;

         ret = av_audio_fifo_peek(s->fifo, (void **)fin->extended_data, s->win_size);
         if (ret < 0)
             goto fail;
 
         ret = plot_freqs(inlink, fin);

         av_frame_free(&fin);

         av_audio_fifo_drain(s->fifo, s->hop_size);

         if (ret < 0)
             goto fail;
     }
 
 fail:

     s->pts = AV_NOPTS_VALUE;

     av_frame_free(&fin);
     av_frame_free(&in);
     return ret;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     ShowFreqsContext *s = ctx->priv;
     int i;
 
     av_fft_end(s->fft);
     for (i = 0; i < s->nb_channels; i++) {

         if (s->fft_data)
             av_freep(&s->fft_data[i]);
         if (s->avg_data)
             av_freep(&s->avg_data[i]);

     }
     av_freep(&s->fft_data);
     av_freep(&s->avg_data);
     av_freep(&s->window_func_lut);
     av_audio_fifo_free(s->fifo);
 }
 
 static const AVFilterPad showfreqs_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad showfreqs_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .config_props  = config_output,
     },
     { NULL }
 };
 
 AVFilter ff_avf_showfreqs = {
     .name          = "showfreqs",
     .description   = NULL_IF_CONFIG_SMALL("Convert input audio to a frequencies video output."),

     .init          = init,

     .uninit        = uninit,
     .query_formats = query_formats,
     .priv_size     = sizeof(ShowFreqsContext),
     .inputs        = showfreqs_inputs,
     .outputs       = showfreqs_outputs,
     .priv_class    = &showfreqs_class,
 };