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FFmpeg/libavfilter/avf_showfreqs.c

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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/(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.         return AVERROR(ENOMEM);

  457. 

  458.     for (ch = 0; ch < s->nb_channels; ch++) {

  459.         uint8_t fg[4] = { 0xff, 0xff, 0xff, 0xff };

  460.         int prev_y = -1, f;

  461.         double a;

  462. 

  463.         color = av_strtok(ch == 0 ? colors : NULL, " |", &saveptr);

  464.         if (color)

  465.             av_parse_color(fg, color, -1, ctx);

  466. 

  467.         a = av_clipd(M(RE(0, ch), 0) / s->scale, 0, 1);

  468.         plot_freq(s, ch, a, 0, fg, &prev_y, out, outlink);

  469. 

  470.         for (f = 1; f < s->nb_freq; f++) {

  471.             a = av_clipd(M(RE(f, ch), IM(f, ch)) / s->scale, 0, 1);

  472. 

  473.             plot_freq(s, ch, a, f, fg, &prev_y, out, outlink);

  474.         }

  475.     }

  476. 

  477.     av_free(colors);

  478.     out->pts = in->pts;

  479.     return ff_filter_frame(outlink, out);

  480. }

  481. 

  482. static int filter_frame(AVFilterLink *inlink, AVFrame *in)

  483. {

  484.     AVFilterContext *ctx = inlink->dst;

  485.     ShowFreqsContext *s = ctx->priv;

  486.     AVFrame *fin = NULL;

  487.     int ret;

  488. 

  489.     av_audio_fifo_write(s->fifo, (void **)in->extended_data, in->nb_samples);

  490.     while (av_audio_fifo_size(s->fifo) >= s->win_size) {

  491.         fin = ff_get_audio_buffer(inlink, s->win_size);

  492.         if (!fin) {

  493.             ret = AVERROR(ENOMEM);

  494.             goto fail;

  495.         }

  496. 

  497.         fin->pts = s->pts;

  498.         s->pts += s->skip_samples;

  499.         ret = av_audio_fifo_peek(s->fifo, (void **)fin->extended_data, s->win_size);

  500.         if (ret < 0)

  501.             goto fail;

  502. 

  503.         ret = plot_freqs(inlink, fin);

  504.         av_audio_fifo_drain(s->fifo, s->skip_samples);

  505.         if (ret < 0)

  506.             goto fail;

  507.     }

  508. 

  509. fail:

  510.     av_frame_free(&fin);

  511.     av_frame_free(&in);

  512.     return ret;

  513. }

  514. 

  515. static av_cold void uninit(AVFilterContext *ctx)

  516. {

  517.     ShowFreqsContext *s = ctx->priv;

  518.     int i;

  519. 

  520.     av_fft_end(s->fft);

  521.     for (i = 0; i < s->nb_channels; i++) {

  522.         av_freep(&s->fft_data[i]);

  523.         av_freep(&s->avg_data[i]);

  524.     }

  525.     av_freep(&s->fft_data);

  526.     av_freep(&s->avg_data);

  527.     av_freep(&s->window_func_lut);

  528.     av_audio_fifo_free(s->fifo);

  529. }

  530. 

  531. static const AVFilterPad showfreqs_inputs[] = {

  532.     {

  533.         .name         = "default",

  534.         .type         = AVMEDIA_TYPE_AUDIO,

  535.         .filter_frame = filter_frame,

  536.     },

  537.     { NULL }

  538. };

  539. 

  540. static const AVFilterPad showfreqs_outputs[] = {

  541.     {

  542.         .name          = "default",

  543.         .type          = AVMEDIA_TYPE_VIDEO,

  544.         .config_props  = config_output,

  545.     },

  546.     { NULL }

  547. };

  548. 

  549. AVFilter ff_avf_showfreqs = {

  550.     .name          = "showfreqs",

  551.     .description   = NULL_IF_CONFIG_SMALL("Convert input audio to a frequencies video output."),

  552.     .uninit        = uninit,

  553.     .query_formats = query_formats,

  554.     .priv_size     = sizeof(ShowFreqsContext),

  555.     .inputs        = showfreqs_inputs,

  556.     .outputs       = showfreqs_outputs,

  557.     .priv_class    = &showfreqs_class,

  558. };