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  1. /*
  2.  * Copyright (c) 2015 Paul B Mahol
  3.  *
  4.  * This file is part of FFmpeg.
  5.  *
  6.  * FFmpeg is free software; you can redistribute it and/or
  7.  * modify it under the terms of the GNU Lesser General Public
  8.  * License as published by the Free Software Foundation; either
  9.  * version 2.1 of the License, or (at your option) any later version.
  10.  *
  11.  * FFmpeg is distributed in the hope that it will be useful,
  12.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14.  * Lesser General Public License for more details.
  15.  *
  16.  * You should have received a copy of the GNU Lesser General Public
  17.  * License along with FFmpeg; if not, write to the Free Software
  18.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19.  */
  20.  
  21. #include <math.h>
  22.  
  23. #include "libavcodec/avfft.h"
  24. #include "libavutil/audio_fifo.h"
  25. #include "libavutil/avassert.h"
  26. #include "libavutil/avstring.h"
  27. #include "libavutil/channel_layout.h"
  28. #include "libavutil/intreadwrite.h"
  29. #include "libavutil/opt.h"
  30. #include "libavutil/parseutils.h"
  31. #include "audio.h"
  32. #include "video.h"
  33. #include "avfilter.h"
  34. #include "internal.h"
  35.  
  36. enum DisplayMode    { LINE, BAR, DOT, NB_MODES };
  37. enum FrequencyScale { FS_LINEAR, FS_LOG, FS_RLOG, NB_FSCALES };
  38. enum AmplitudeScale { AS_LINEAR, AS_SQRT, AS_CBRT, AS_LOG, NB_ASCALES };
  39. enum WindowFunc     { WFUNC_RECT, WFUNC_HANNING, WFUNC_HAMMING, WFUNC_BLACKMAN,
  40.                       WFUNC_BARTLETT, WFUNC_WELCH, WFUNC_FLATTOP,
  41.                       WFUNC_BHARRIS, WFUNC_BNUTTALL, WFUNC_SINE, WFUNC_NUTTALL,
  42.                       WFUNC_BHANN, NB_WFUNC };
  43.  
  44. typedef struct ShowFreqsContext {
  45.     const AVClass *class;
  46.     int w, h;
  47.     int mode;
  48.     int fft_bits;
  49.     int ascale, fscale;
  50.     int avg;
  51.     int win_func;
  52.     FFTContext *fft;
  53.     FFTComplex **fft_data;
  54.     float **avg_data;
  55.     float *window_func_lut;
  56.     float overlap;
  57.     int skip_samples;
  58.     int nb_channels;
  59.     int nb_freq;
  60.     int win_size;
  61.     float scale;
  62.     char *colors;
  63.     AVAudioFifo *fifo;
  64.     int64_t pts;
  65. } ShowFreqsContext;
  66.  
  67. #define OFFSET(x) offsetof(ShowFreqsContext, x)
  68. #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
  69.  
  70. static const AVOption showfreqs_options[] = {
  71.     { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "1024x512"}, 0, 0, FLAGS },
  72.     { "s",    "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "1024x512"}, 0, 0, FLAGS },
  73.     { "mode", "set display mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=BAR}, 0, NB_MODES-1, FLAGS, "mode" },
  74.         { "line", "show lines",  0, AV_OPT_TYPE_CONST, {.i64=LINE},   0, 0, FLAGS, "mode" },
  75.         { "bar",  "show bars",   0, AV_OPT_TYPE_CONST, {.i64=BAR},    0, 0, FLAGS, "mode" },
  76.         { "dot",  "show dots",   0, AV_OPT_TYPE_CONST, {.i64=DOT},    0, 0, FLAGS, "mode" },
  77.     { "ascale", "set amplitude scale", OFFSET(ascale), AV_OPT_TYPE_INT, {.i64=AS_LOG}, 0, NB_ASCALES-1, FLAGS, "ascale" },
  78.         { "lin",  "linear",      0, AV_OPT_TYPE_CONST, {.i64=AS_LINEAR}, 0, 0, FLAGS, "ascale" },
  79.         { "sqrt", "square root", 0, AV_OPT_TYPE_CONST, {.i64=AS_SQRT},   0, 0, FLAGS, "ascale" },
  80.         { "cbrt", "cubic root",  0, AV_OPT_TYPE_CONST, {.i64=AS_CBRT},   0, 0, FLAGS, "ascale" },
  81.         { "log",  "logarithmic", 0, AV_OPT_TYPE_CONST, {.i64=AS_LOG},    0, 0, FLAGS, "ascale" },
  82.     { "fscale", "set frequency scale", OFFSET(fscale), AV_OPT_TYPE_INT, {.i64=FS_LINEAR}, 0, NB_FSCALES-1, FLAGS, "fscale" },
  83.         { "lin",  "linear",              0, AV_OPT_TYPE_CONST, {.i64=FS_LINEAR}, 0, 0, FLAGS, "fscale" },
  84.         { "log",  "logarithmic",         0, AV_OPT_TYPE_CONST, {.i64=FS_LOG},    0, 0, FLAGS, "fscale" },
  85.         { "rlog", "reverse logarithmic", 0, AV_OPT_TYPE_CONST, {.i64=FS_RLOG},   0, 0, FLAGS, "fscale" },
  86.     { "win_size", "set window size", OFFSET(fft_bits), AV_OPT_TYPE_INT, {.i64=11}, 4, 16, FLAGS, "fft" },
  87.         { "w16",    0, 0, AV_OPT_TYPE_CONST, {.i64=4},  0, 0, FLAGS, "fft" },
  88.         { "w32",    0, 0, AV_OPT_TYPE_CONST, {.i64=5},  0, 0, FLAGS, "fft" },
  89.         { "w64",    0, 0, AV_OPT_TYPE_CONST, {.i64=6},  0, 0, FLAGS, "fft" },
  90.         { "w128",   0, 0, AV_OPT_TYPE_CONST, {.i64=7},  0, 0, FLAGS, "fft" },
  91.         { "w256",   0, 0, AV_OPT_TYPE_CONST, {.i64=8},  0, 0, FLAGS, "fft" },
  92.         { "w512",   0, 0, AV_OPT_TYPE_CONST, {.i64=9},  0, 0, FLAGS, "fft" },
  93.         { "w1024",  0, 0, AV_OPT_TYPE_CONST, {.i64=10}, 0, 0, FLAGS, "fft" },
  94.         { "w2048",  0, 0, AV_OPT_TYPE_CONST, {.i64=11}, 0, 0, FLAGS, "fft" },
  95.         { "w4096",  0, 0, AV_OPT_TYPE_CONST, {.i64=12}, 0, 0, FLAGS, "fft" },
  96.         { "w8192",  0, 0, AV_OPT_TYPE_CONST, {.i64=13}, 0, 0, FLAGS, "fft" },
  97.         { "w16384", 0, 0, AV_OPT_TYPE_CONST, {.i64=14}, 0, 0, FLAGS, "fft" },
  98.         { "w32768", 0, 0, AV_OPT_TYPE_CONST, {.i64=15}, 0, 0, FLAGS, "fft" },
  99.         { "w65536", 0, 0, AV_OPT_TYPE_CONST, {.i64=16}, 0, 0, FLAGS, "fft" },
  100.     { "win_func", "set window function", OFFSET(win_func), AV_OPT_TYPE_INT, {.i64=WFUNC_HANNING}, 0, NB_WFUNC-1, FLAGS, "win_func" },
  101.         { "rect",     "Rectangular",      0, AV_OPT_TYPE_CONST, {.i64=WFUNC_RECT},     0, 0, FLAGS, "win_func" },
  102.         { "bartlett", "Bartlett",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BARTLETT}, 0, 0, FLAGS, "win_func" },
  103.         { "hanning",  "Hanning",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING},  0, 0, FLAGS, "win_func" },
  104.         { "hamming",  "Hamming",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HAMMING},  0, 0, FLAGS, "win_func" },
  105.         { "blackman", "Blackman",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BLACKMAN}, 0, 0, FLAGS, "win_func" },
  106.         { "welch",    "Welch",            0, AV_OPT_TYPE_CONST, {.i64=WFUNC_WELCH},    0, 0, FLAGS, "win_func" },
  107.         { "flattop",  "Flat-top",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_FLATTOP},  0, 0, FLAGS, "win_func" },
  108.         { "bharris",  "Blackman-Harris",  0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BHARRIS},  0, 0, FLAGS, "win_func" },
  109.         { "bnuttall", "Blackman-Nuttall", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BNUTTALL}, 0, 0, FLAGS, "win_func" },
  110.         { "bhann",    "Bartlett-Hann",    0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BHANN},    0, 0, FLAGS, "win_func" },
  111.         { "sine",     "Sine",             0, AV_OPT_TYPE_CONST, {.i64=WFUNC_SINE},     0, 0, FLAGS, "win_func" },
  112.         { "nuttall",  "Nuttall",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_NUTTALL},  0, 0, FLAGS, "win_func" },
  113.     { "overlap",  "set window overlap", OFFSET(overlap), AV_OPT_TYPE_FLOAT, {.dbl=1.}, 0., 1., FLAGS },
  114.     { "averaging", "set time averaging", OFFSET(avg), AV_OPT_TYPE_INT, {.i64=1}, 0, INT32_MAX, FLAGS },
  115.     { "colors", "set channels colors", OFFSET(colors), AV_OPT_TYPE_STRING, {.str = "red|green|blue|yellow|orange|lime|pink|magenta|brown" }, 0, 0, FLAGS },
  116.     { NULL }
  117. };
  118.  
  119. AVFILTER_DEFINE_CLASS(showfreqs);
  120.  
  121. static int query_formats(AVFilterContext *ctx)
  122. {
  123.     AVFilterFormats *formats = NULL;
  124.     AVFilterChannelLayouts *layouts = NULL;
  125.     AVFilterLink *inlink = ctx->inputs[0];
  126.     AVFilterLink *outlink = ctx->outputs[0];
  127.     static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_NONE };
  128.     static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_RGBA, AV_PIX_FMT_NONE };
  129.  
  130.     /* set input audio formats */
  131.     formats = ff_make_format_list(sample_fmts);
  132.     if (!formats)
  133.         return AVERROR(ENOMEM);
  134.     ff_formats_ref(formats, &inlink->out_formats);
  135.  
  136.     layouts = ff_all_channel_layouts();
  137.     if (!layouts)
  138.         return AVERROR(ENOMEM);
  139.     ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);
  140.  
  141.     formats = ff_all_samplerates();
  142.     if (!formats)
  143.         return AVERROR(ENOMEM);
  144.     ff_formats_ref(formats, &inlink->out_samplerates);
  145.  
  146.     /* set output video format */
  147.     formats = ff_make_format_list(pix_fmts);
  148.     if (!formats)
  149.         return AVERROR(ENOMEM);
  150.     ff_formats_ref(formats, &outlink->in_formats);
  151.  
  152.     return 0;
  153. }
  154.  
  155. static void generate_window_func(float *lut, int N, int win_func, float *overlap)
  156. {
  157.     int n;
  158.  
  159.     switch (win_func) {
  160.     case WFUNC_RECT:
  161.         for (n = 0; n < N; n++)
  162.             lut[n] = 1.;
  163.         *overlap = 0.;
  164.         break;
  165.     case WFUNC_BARTLETT:
  166.         for (n = 0; n < N; n++)
  167.             lut[n] = 1.-FFABS((n-(N-1)/2.)/((N-1)/2.));
  168.         *overlap = 0.5;
  169.         break;
  170.     case WFUNC_HANNING:
  171.         for (n = 0; n < N; n++)
  172.             lut[n] = .5*(1-cos(2*M_PI*n/(N-1)));
  173.         *overlap = 0.5;
  174.         break;
  175.     case WFUNC_HAMMING:
  176.         for (n = 0; n < N; n++)
  177.             lut[n] = .54-.46*cos(2*M_PI*n/(N-1));
  178.         *overlap = 0.5;
  179.         break;
  180.     case WFUNC_BLACKMAN:
  181.         for (n = 0; n < N; n++)
  182.             lut[n] = .42659-.49656*cos(2*M_PI*n/(N-1))+.076849*cos(4*M_PI*n/(N-1));
  183.         *overlap = 0.661;
  184.         break;
  185.     case WFUNC_WELCH:
  186.         for (n = 0; n < N; n++)
  187.             lut[n] = 1.-(n-(N-1)/2.)/((N-1)/2.)*(n-(N-1)/2.)/((N-1)/2.);
  188.         *overlap = 0.293;
  189.         break;
  190.     case WFUNC_FLATTOP:
  191.         for (n = 0; n < N; n++)
  192.             lut[n] = 1.-1.985844164102*cos( 2*M_PI*n/(N-1))+1.791176438506*cos( 4*M_PI*n/(N-1))-
  193.                         1.282075284005*cos( 6*M_PI*n/(N-1))+0.667777530266*cos( 8*M_PI*n/(N-1))-
  194.                         0.240160796576*cos(10*M_PI*n/(N-1))+0.056656381764*cos(12*M_PI*n/(N-1))-
  195.                         0.008134974479*cos(14*M_PI*n/(N-1))+0.000624544650*cos(16*M_PI*n/(N-1))-
  196.                         0.000019808998*cos(18*M_PI*n/(N-1))+0.000000132974*cos(20*M_PI*n/(N-1));
  197.         *overlap = 0.841;
  198.         break;
  199.     case WFUNC_BHARRIS:
  200.         for (n = 0; n < N; n++)
  201.             lut[n] = 0.35875-0.48829*cos(2*M_PI*n/(N-1))+0.14128*cos(4*M_PI*n/(N-1))-0.01168*cos(6*M_PI*n/(N-1));
  202.         *overlap = 0.661;
  203.         break;
  204.     case WFUNC_BNUTTALL:
  205.         for (n = 0; n < N; n++)
  206.             lut[n] = 0.3635819-0.4891775*cos(2*M_PI*n/(N-1))+0.1365995*cos(4*M_PI*n/(N-1))-0.0106411*cos(6*M_PI*n/(N-1));
  207.         *overlap = 0.661;
  208.         break;
  209.     case WFUNC_BHANN:
  210.         for (n = 0; n < N; n++)
  211.             lut[n] = 0.62-0.48*FFABS(n/(double)(N-1)-.5)-0.38*cos(2*M_PI*n/(N-1));
  212.         *overlap = 0.5;
  213.         break;
  214.     case WFUNC_SINE:
  215.         for (n = 0; n < N; n++)
  216.             lut[n] = sin(M_PI*n/(N-1));
  217.         *overlap = 0.75;
  218.         break;
  219.     case WFUNC_NUTTALL:
  220.         for (n = 0; n < N; n++)
  221.             lut[n] = 0.355768-0.487396*cos(2*M_PI*n/(N-1))+0.144232*cos(4*M_PI*n/(N-1))-0.012604*cos(6*M_PI*n/(N-1));
  222.         *overlap = 0.663;
  223.         break;
  224.     default:
  225.         av_assert0(0);
  226.     }
  227. }
  228.  
  229. static int config_output(AVFilterLink *outlink)
  230. {
  231.     AVFilterContext *ctx = outlink->src;
  232.     AVFilterLink *inlink = ctx->inputs[0];
  233.     ShowFreqsContext *s = ctx->priv;
  234.     float overlap;
  235.     int i;
  236.  
  237.     s->nb_freq = 1 << (s->fft_bits - 1);
  238.     s->win_size = s->nb_freq << 1;
  239.     av_audio_fifo_free(s->fifo);
  240.     av_fft_end(s->fft);
  241.     s->fft = av_fft_init(s->fft_bits, 0);
  242.     if (!s->fft) {
  243.         av_log(ctx, AV_LOG_ERROR, "Unable to create FFT context. "
  244.                "The window size might be too high.\n");
  245.         return AVERROR(ENOMEM);
  246.     }
  247.  
  248.     /* FFT buffers: x2 for each (display) channel buffer.
  249.      * Note: we use free and malloc instead of a realloc-like function to
  250.      * make sure the buffer is aligned in memory for the FFT functions. */
  251.     for (i = 0; i < s->nb_channels; i++) {
  252.         av_freep(&s->fft_data[i]);
  253.         av_freep(&s->avg_data[i]);
  254.     }
  255.     av_freep(&s->fft_data);
  256.     av_freep(&s->avg_data);
  257.     s->nb_channels = inlink->channels;
  258.  
  259.     s->fft_data = av_calloc(s->nb_channels, sizeof(*s->fft_data));
  260.     if (!s->fft_data)
  261.         return AVERROR(ENOMEM);
  262.     s->avg_data = av_calloc(s->nb_channels, sizeof(*s->avg_data));
  263.     if (!s->fft_data)
  264.         return AVERROR(ENOMEM);
  265.     for (i = 0; i < s->nb_channels; i++) {
  266.         s->fft_data[i] = av_calloc(s->win_size, sizeof(**s->fft_data));
  267.         s->avg_data[i] = av_calloc(s->nb_freq, sizeof(**s->avg_data));
  268.         if (!s->fft_data[i] || !s->avg_data[i])
  269.             return AVERROR(ENOMEM);
  270.     }
  271.  
  272.     /* pre-calc windowing function */
  273.     s->window_func_lut = av_realloc_f(s->window_func_lut, s->win_size,
  274.                                       sizeof(*s->window_func_lut));
  275.     if (!s->window_func_lut)
  276.         return AVERROR(ENOMEM);
  277.     generate_window_func(s->window_func_lut, s->win_size, s->win_func, &overlap);
  278.     if (s->overlap == 1.)
  279.         s->overlap = overlap;
  280.     s->skip_samples = (1. - s->overlap) * s->win_size;
  281.     if (s->skip_samples < 1) {
  282.         av_log(ctx, AV_LOG_ERROR, "overlap %f too big\n", s->overlap);
  283.         return AVERROR(EINVAL);
  284.     }
  285.  
  286.     for (s->scale = 0, i = 0; i < s->win_size; i++) {
  287.         s->scale += s->window_func_lut[i] * s->window_func_lut[i];
  288.     }
  289.  
  290.     outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
  291.     outlink->frame_rate = av_make_q(inlink->sample_rate, s->win_size * (1.-s->overlap));
  292.     outlink->sample_aspect_ratio = (AVRational){1,1};
  293.     outlink->w = s->w;
  294.     outlink->h = s->h;
  295.  
  296.     s->fifo = av_audio_fifo_alloc(inlink->format, inlink->channels, s->win_size);
  297.     if (!s->fifo)
  298.         return AVERROR(ENOMEM);
  299.     return 0;
  300. }
  301.  
  302. static inline void draw_dot(AVFrame *out, int x, int y, uint8_t fg[4])
  303. {
  304.  
  305.     uint32_t color = AV_RL32(out->data[0] + y * out->linesize[0] + x * 4);
  306.  
  307.     if ((color & 0xffffff) != 0)
  308.         AV_WL32(out->data[0] + y * out->linesize[0] + x * 4, AV_RL32(fg) | color);
  309.     else
  310.         AV_WL32(out->data[0] + y * out->linesize[0] + x * 4, AV_RL32(fg));
  311. }
  312.  
  313. static int get_sx(ShowFreqsContext *s, int f)
  314. {
  315.     switch (s->fscale) {
  316.     case FS_LINEAR:
  317.         return (s->w/(float)s->nb_freq)*f;
  318.     case FS_LOG:
  319.         return s->w-pow(s->w, (s->nb_freq-f-1)/(s->nb_freq-1.));
  320.     case FS_RLOG:
  321.         return pow(s->w, f/(s->nb_freq-1.));
  322.     }
  323.  
  324.     return 0;
  325. }
  326.  
  327. static float get_bsize(ShowFreqsContext *s, int f)
  328. {
  329.     switch (s->fscale) {
  330.     case FS_LINEAR:
  331.         return s->w/(float)s->nb_freq;
  332.     case FS_LOG:
  333.         return pow(s->w, (s->nb_freq-f-1)/(s->nb_freq-1.))-
  334.                pow(s->w, (s->nb_freq-f-2)/(s->nb_freq-1.));
  335.     case FS_RLOG:
  336.         return pow(s->w, (f+1)/(s->nb_freq-1.))-
  337.                pow(s->w,  f   /(s->nb_freq-1.));
  338.     }
  339.  
  340.     return 1.;
  341. }
  342.  
  343. static inline void plot_freq(ShowFreqsContext *s, int ch,
  344.                              double a, int f, uint8_t fg[4], int *prev_y,
  345.                              AVFrame *out, AVFilterLink *outlink)
  346. {
  347.     const int w = s->w;
  348.     const float avg = s->avg_data[ch][f];
  349.     const float bsize = get_bsize(s, f);
  350.     const int sx = get_sx(s, f);
  351.     int x, y, i;
  352.  
  353.     switch(s->ascale) {
  354.     case AS_SQRT:
  355.         a = 1.0 - sqrt(a);
  356.         break;
  357.     case AS_CBRT:
  358.         a = 1.0 - cbrt(a);
  359.         break;
  360.     case AS_LOG:
  361.         a = log(av_clipd(a, 1e-6, 1)) / log(1e-6);
  362.         break;
  363.     case AS_LINEAR:
  364.         a = 1.0 - a;
  365.         break;
  366.     }
  367.     y = a * outlink->h - 1;
  368.     if (y < 0)
  369.         return;
  370.  
  371.     switch (s->avg) {
  372.     case 0:
  373.         y = s->avg_data[ch][f] = !outlink->frame_count ? y : FFMIN(avg, y);
  374.         break;
  375.     case 1:
  376.         break;
  377.     default:
  378.         s->avg_data[ch][f] = avg + y * (y - avg) / (FFMIN(outlink->frame_count + 1, s->avg) * y);
  379.         y = s->avg_data[ch][f];
  380.         break;
  381.     }
  382.  
  383.     switch(s->mode) {
  384.     case LINE:
  385.         if (*prev_y == -1) {
  386.             *prev_y = y;
  387.         }
  388.         if (y <= *prev_y) {
  389.             for (x = sx + 1; x < sx + bsize && x < w; x++)
  390.                 draw_dot(out, x, y, fg);
  391.             for (i = y; i <= *prev_y; i++)
  392.                 draw_dot(out, sx, i, fg);
  393.         } else {
  394.             for (i = *prev_y; i <= y; i++)
  395.                 draw_dot(out, sx, i, fg);
  396.             for (x = sx + 1; x < sx + bsize && x < w; x++)
  397.                 draw_dot(out, x, i - 1, fg);
  398.         }
  399.         *prev_y = y;
  400.         break;
  401.     case BAR:
  402.         for (x = sx; x < sx + bsize && x < w; x++)
  403.             for (i = y; i < outlink->h; i++)
  404.                 draw_dot(out, x, i, fg);
  405.         break;
  406.     case DOT:
  407.         for (x = sx; x < sx + bsize && x < w; x++)
  408.             draw_dot(out, x, y, fg);
  409.         break;
  410.     }
  411. }
  412.  
  413. static int plot_freqs(AVFilterLink *inlink, AVFrame *in)
  414. {
  415.     AVFilterContext *ctx = inlink->dst;
  416.     AVFilterLink *outlink = ctx->outputs[0];
  417.     ShowFreqsContext *s = ctx->priv;
  418.     const int win_size = s->win_size;
  419.     char *colors, *color, *saveptr = NULL;
  420.     AVFrame *out;
  421.     int ch, n;
  422.  
  423.     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
  424.     if (!out)
  425.         return AVERROR(ENOMEM);
  426.  
  427.     for (n = 0; n < outlink->h; n++)
  428.         memset(out->data[0] + out->linesize[0] * n, 0, outlink->w * 4);
  429.  
  430.     /* fill FFT input with the number of samples available */
  431.     for (ch = 0; ch < s->nb_channels; ch++) {
  432.         const float *p = (float *)in->extended_data[ch];
  433.  
  434.         for (n = 0; n < in->nb_samples; n++) {
  435.             s->fft_data[ch][n].re = p[n] * s->window_func_lut[n];
  436.             s->fft_data[ch][n].im = 0;
  437.         }
  438.         for (; n < win_size; n++) {
  439.             s->fft_data[ch][n].re = 0;
  440.             s->fft_data[ch][n].im = 0;
  441.         }
  442.     }
  443.  
  444.     /* run FFT on each samples set */
  445.     for (ch = 0; ch < s->nb_channels; ch++) {
  446.         av_fft_permute(s->fft, s->fft_data[ch]);
  447.         av_fft_calc(s->fft, s->fft_data[ch]);
  448.     }
  449.  
  450. #define RE(x, ch) s->fft_data[ch][x].re
  451. #define IM(x, ch) s->fft_data[ch][x].im
  452. #define M(a, b) (sqrt((a) * (a) + (b) * (b)))
  453.  
  454.     colors = av_strdup(s->colors);
  455.     if (!colors) {
  456.         av_frame_free(&out);
  457.         return AVERROR(ENOMEM);
  458.     }
  459.  
  460.     for (ch = 0; ch < s->nb_channels; ch++) {
  461.         uint8_t fg[4] = { 0xff, 0xff, 0xff, 0xff };
  462.         int prev_y = -1, f;
  463.         double a;
  464.  
  465.         color = av_strtok(ch == 0 ? colors : NULL, " |", &saveptr);
  466.         if (color)
  467.             av_parse_color(fg, color, -1, ctx);
  468.  
  469.         a = av_clipd(M(RE(0, ch), 0) / s->scale, 0, 1);
  470.         plot_freq(s, ch, a, 0, fg, &prev_y, out, outlink);
  471.  
  472.         for (f = 1; f < s->nb_freq; f++) {
  473.             a = av_clipd(M(RE(f, ch), IM(f, ch)) / s->scale, 0, 1);
  474.  
  475.             plot_freq(s, ch, a, f, fg, &prev_y, out, outlink);
  476.         }
  477.     }
  478.  
  479.     av_free(colors);
  480.     out->pts = in->pts;
  481.     return ff_filter_frame(outlink, out);
  482. }
  483.  
  484. static int filter_frame(AVFilterLink *inlink, AVFrame *in)
  485. {
  486.     AVFilterContext *ctx = inlink->dst;
  487.     ShowFreqsContext *s = ctx->priv;
  488.     AVFrame *fin = NULL;
  489.     int ret = 0;
  490.  
  491.     av_audio_fifo_write(s->fifo, (void **)in->extended_data, in->nb_samples);
  492.     while (av_audio_fifo_size(s->fifo) >= s->win_size) {
  493.         fin = ff_get_audio_buffer(inlink, s->win_size);
  494.         if (!fin) {
  495.             ret = AVERROR(ENOMEM);
  496.             goto fail;
  497.         }
  498.  
  499.         fin->pts = s->pts;
  500.         s->pts += s->skip_samples;
  501.         ret = av_audio_fifo_peek(s->fifo, (void **)fin->extended_data, s->win_size);
  502.         if (ret < 0)
  503.             goto fail;
  504.  
  505.         ret = plot_freqs(inlink, fin);
  506.         av_frame_free(&fin);
  507.         av_audio_fifo_drain(s->fifo, s->skip_samples);
  508.         if (ret < 0)
  509.             goto fail;
  510.     }
  511.  
  512. fail:
  513.     av_frame_free(&fin);
  514.     av_frame_free(&in);
  515.     return ret;
  516. }
  517.  
  518. static av_cold void uninit(AVFilterContext *ctx)
  519. {
  520.     ShowFreqsContext *s = ctx->priv;
  521.     int i;
  522.  
  523.     av_fft_end(s->fft);
  524.     for (i = 0; i < s->nb_channels; i++) {
  525.         av_freep(&s->fft_data[i]);
  526.         av_freep(&s->avg_data[i]);
  527.     }
  528.     av_freep(&s->fft_data);
  529.     av_freep(&s->avg_data);
  530.     av_freep(&s->window_func_lut);
  531.     av_audio_fifo_free(s->fifo);
  532. }
  533.  
  534. static const AVFilterPad showfreqs_inputs[] = {
  535.     {
  536.         .name         = "default",
  537.         .type         = AVMEDIA_TYPE_AUDIO,
  538.         .filter_frame = filter_frame,
  539.     },
  540.     { NULL }
  541. };
  542.  
  543. static const AVFilterPad showfreqs_outputs[] = {
  544.     {
  545.         .name          = "default",
  546.         .type          = AVMEDIA_TYPE_VIDEO,
  547.         .config_props  = config_output,
  548.     },
  549.     { NULL }
  550. };
  551.  
  552. AVFilter ff_avf_showfreqs = {
  553.     .name          = "showfreqs",
  554.     .description   = NULL_IF_CONFIG_SMALL("Convert input audio to a frequencies video output."),
  555.     .uninit        = uninit,
  556.     .query_formats = query_formats,
  557.     .priv_size     = sizeof(ShowFreqsContext),
  558.     .inputs        = showfreqs_inputs,
  559.     .outputs       = showfreqs_outputs,
  560.     .priv_class    = &showfreqs_class,
  561. };
  562.