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FFmpeg/libavfilter/avf_showspectrum.c

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  1. /*

  2.  * Copyright (c) 2012-2013 Clément Bœsch

  3.  * Copyright (c) 2013 Rudolf Polzer <divverent@xonotic.org>

  4.  *

  5.  * This file is part of FFmpeg.

  6.  *

  7.  * FFmpeg is free software; you can redistribute it and/or

  8.  * modify it under the terms of the GNU Lesser General Public

  9.  * License as published by the Free Software Foundation; either

  10.  * version 2.1 of the License, or (at your option) any later version.

  11.  *

  12.  * FFmpeg is distributed in the hope that it will be useful,

  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

  15.  * Lesser General Public License for more details.

  16.  *

  17.  * You should have received a copy of the GNU Lesser General Public

  18.  * License along with FFmpeg; if not, write to the Free Software

  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  20.  */

  21. 

  22. /**

  23.  * @file

  24.  * audio to spectrum (video) transmedia filter, based on ffplay rdft showmode

  25.  * (by Michael Niedermayer) and lavfi/avf_showwaves (by Stefano Sabatini).

  26.  */

  27. 

  28. #include <math.h>

  29. 

  30. #include "libavcodec/avfft.h"

  31. #include "libavutil/avassert.h"

  32. #include "libavutil/channel_layout.h"

  33. #include "libavutil/opt.h"

  34. #include "avfilter.h"

  35. #include "internal.h"

  36. #include "window_func.h"

  37. 

  38. enum DisplayMode  { COMBINED, SEPARATE, NB_MODES };

  39. enum DisplayScale { LINEAR, SQRT, CBRT, LOG, NB_SCALES };

  40. enum ColorMode    { CHANNEL, INTENSITY, NB_CLMODES };

  41. enum SlideMode    { REPLACE, SCROLL, FULLFRAME, RSCROLL, NB_SLIDES };

  42. enum Orientation  { VERTICAL, HORIZONTAL, NB_ORIENTATIONS };

  43. 

  44. typedef struct {

  45.     const AVClass *class;

  46.     int w, h;

  47.     AVFrame *outpicref;

  48.     int nb_display_channels;

  49.     int orientation;

  50.     int channel_width;

  51.     int channel_height;

  52.     int sliding;                ///< 1 if sliding mode, 0 otherwise

  53.     int mode;                   ///< channel display mode

  54.     int color_mode;             ///< display color scheme

  55.     int scale;

  56.     float saturation;           ///< color saturation multiplier

  57.     int xpos;                   ///< x position (current column)

  58.     RDFTContext *rdft;          ///< Real Discrete Fourier Transform context

  59.     int rdft_bits;              ///< number of bits (RDFT window size = 1<<rdft_bits)

  60.     FFTSample **rdft_data;      ///< bins holder for each (displayed) channels

  61.     float *window_func_lut;     ///< Window function LUT

  62.     int win_func;

  63.     double win_scale;

  64.     float overlap;

  65.     float *combine_buffer;      ///< color combining buffer (3 * h items)

  66. } ShowSpectrumContext;

  67. 

  68. #define OFFSET(x) offsetof(ShowSpectrumContext, x)

  69. #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

  70. 

  71. static const AVOption showspectrum_options[] = {

  72.     { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "640x512"}, 0, 0, FLAGS },

  73.     { "s",    "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "640x512"}, 0, 0, FLAGS },

  74.     { "slide", "set sliding mode", OFFSET(sliding), AV_OPT_TYPE_INT, {.i64 = 0}, 0, NB_SLIDES-1, FLAGS, "slide" },

  75.         { "replace", "replace old columns with new", 0, AV_OPT_TYPE_CONST, {.i64=REPLACE}, 0, 0, FLAGS, "slide" },

  76.         { "scroll", "scroll from right to left", 0, AV_OPT_TYPE_CONST, {.i64=SCROLL}, 0, 0, FLAGS, "slide" },

  77.         { "rscroll", "scroll from left to right", 0, AV_OPT_TYPE_CONST, {.i64=RSCROLL}, 0, 0, FLAGS, "slide" },

  78.         { "fullframe", "return full frames", 0, AV_OPT_TYPE_CONST, {.i64=FULLFRAME}, 0, 0, FLAGS, "slide" },

  79.     { "mode", "set channel display mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=COMBINED}, COMBINED, NB_MODES-1, FLAGS, "mode" },

  80.         { "combined", "combined mode", 0, AV_OPT_TYPE_CONST, {.i64=COMBINED}, 0, 0, FLAGS, "mode" },

  81.         { "separate", "separate mode", 0, AV_OPT_TYPE_CONST, {.i64=SEPARATE}, 0, 0, FLAGS, "mode" },

  82.     { "color", "set channel coloring", OFFSET(color_mode), AV_OPT_TYPE_INT, {.i64=CHANNEL}, CHANNEL, NB_CLMODES-1, FLAGS, "color" },

  83.         { "channel",   "separate color for each channel", 0, AV_OPT_TYPE_CONST, {.i64=CHANNEL},   0, 0, FLAGS, "color" },

  84.         { "intensity", "intensity based coloring",        0, AV_OPT_TYPE_CONST, {.i64=INTENSITY}, 0, 0, FLAGS, "color" },

  85.     { "scale", "set display scale", OFFSET(scale), AV_OPT_TYPE_INT, {.i64=SQRT}, LINEAR, NB_SCALES-1, FLAGS, "scale" },

  86.         { "sqrt", "square root", 0, AV_OPT_TYPE_CONST, {.i64=SQRT},   0, 0, FLAGS, "scale" },

  87.         { "cbrt", "cubic root",  0, AV_OPT_TYPE_CONST, {.i64=CBRT},   0, 0, FLAGS, "scale" },

  88.         { "log",  "logarithmic", 0, AV_OPT_TYPE_CONST, {.i64=LOG},    0, 0, FLAGS, "scale" },

  89.         { "lin",  "linear",      0, AV_OPT_TYPE_CONST, {.i64=LINEAR}, 0, 0, FLAGS, "scale" },

  90.     { "saturation", "color saturation multiplier", OFFSET(saturation), AV_OPT_TYPE_FLOAT, {.dbl = 1}, -10, 10, FLAGS },

  91.     { "win_func", "set window function", OFFSET(win_func), AV_OPT_TYPE_INT, {.i64 = WFUNC_HANNING}, 0, NB_WFUNC-1, FLAGS, "win_func" },

  92.         { "rect",     "Rectangular",      0, AV_OPT_TYPE_CONST, {.i64=WFUNC_RECT},     0, 0, FLAGS, "win_func" },

  93.         { "bartlett", "Bartlett",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BARTLETT}, 0, 0, FLAGS, "win_func" },

  94.         { "hann",     "Hann",             0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING},  0, 0, FLAGS, "win_func" },

  95.         { "hanning",  "Hanning",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING},  0, 0, FLAGS, "win_func" },

  96.         { "hamming",  "Hamming",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HAMMING},  0, 0, FLAGS, "win_func" },

  97.         { "blackman", "Blackman",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BLACKMAN}, 0, 0, FLAGS, "win_func" },

  98.         { "welch",    "Welch",            0, AV_OPT_TYPE_CONST, {.i64=WFUNC_WELCH},    0, 0, FLAGS, "win_func" },

  99.         { "flattop",  "Flat-top",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_FLATTOP},  0, 0, FLAGS, "win_func" },

  100.         { "bharris",  "Blackman-Harris",  0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BHARRIS},  0, 0, FLAGS, "win_func" },

  101.         { "bnuttall", "Blackman-Nuttall", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BNUTTALL}, 0, 0, FLAGS, "win_func" },

  102.         { "bhann",    "Bartlett-Hann",    0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BHANN},    0, 0, FLAGS, "win_func" },

  103.         { "sine",     "Sine",             0, AV_OPT_TYPE_CONST, {.i64=WFUNC_SINE},     0, 0, FLAGS, "win_func" },

  104.         { "nuttall",  "Nuttall",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_NUTTALL},  0, 0, FLAGS, "win_func" },

  105.         { "lanczos",  "Lanczos",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_LANCZOS},  0, 0, FLAGS, "win_func" },

  106.         { "gauss",    "Gauss",            0, AV_OPT_TYPE_CONST, {.i64=WFUNC_GAUSS},    0, 0, FLAGS, "win_func" },

  107.     { "orientation", "set orientation", OFFSET(orientation), AV_OPT_TYPE_INT, {.i64=VERTICAL}, 0, NB_ORIENTATIONS-1, FLAGS, "orientation" },

  108.         { "vertical",   NULL, 0, AV_OPT_TYPE_CONST, {.i64=VERTICAL},   0, 0, FLAGS, "orientation" },

  109.         { "horizontal", NULL, 0, AV_OPT_TYPE_CONST, {.i64=HORIZONTAL}, 0, 0, FLAGS, "orientation" },

  110.     { NULL }

  111. };

  112. 

  113. AVFILTER_DEFINE_CLASS(showspectrum);

  114. 

  115. static const struct {

  116.     float a, y, u, v;

  117. } intensity_color_table[] = {

  118.     {    0,                  0,                  0,                   0 },

  119.     { 0.13, .03587126228984074,  .1573300977624594, -.02548747583751842 },

  120.     { 0.30, .18572281794568020,  .1772436246393981,  .17475554840414750 },

  121.     { 0.60, .28184980583656130, -.1593064119945782,  .47132074554608920 },

  122.     { 0.73, .65830621175547810, -.3716070802232764,  .24352759331252930 },

  123.     { 0.78, .76318535758242900, -.4307467689263783,  .16866496622310430 },

  124.     { 0.91, .95336363636363640, -.2045454545454546,  .03313636363636363 },

  125.     {    1,                  1,                  0,                   0 }

  126. };

  127. 

  128. static av_cold void uninit(AVFilterContext *ctx)

  129. {

  130.     ShowSpectrumContext *s = ctx->priv;

  131.     int i;

  132. 

  133.     av_freep(&s->combine_buffer);

  134.     av_rdft_end(s->rdft);

  135.     for (i = 0; i < s->nb_display_channels; i++)

  136.         av_freep(&s->rdft_data[i]);

  137.     av_freep(&s->rdft_data);

  138.     av_freep(&s->window_func_lut);

  139.     av_frame_free(&s->outpicref);

  140. }

  141. 

  142. static int query_formats(AVFilterContext *ctx)

  143. {

  144.     AVFilterFormats *formats = NULL;

  145.     AVFilterChannelLayouts *layouts = NULL;

  146.     AVFilterLink *inlink = ctx->inputs[0];

  147.     AVFilterLink *outlink = ctx->outputs[0];

  148.     static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_S16P, AV_SAMPLE_FMT_NONE };

  149.     static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_NONE };

  150.     int ret;

  151. 

  152.     /* set input audio formats */

  153.     formats = ff_make_format_list(sample_fmts);

  154.     if ((ret = ff_formats_ref(formats, &inlink->out_formats)) < 0)

  155.         return ret;

  156. 

  157.     layouts = ff_all_channel_layouts();

  158.     if ((ret = ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts)) < 0)

  159.         return ret;

  160. 

  161.     formats = ff_all_samplerates();

  162.     if ((ret = ff_formats_ref(formats, &inlink->out_samplerates)) < 0)

  163.         return ret;

  164. 

  165.     /* set output video format */

  166.     formats = ff_make_format_list(pix_fmts);

  167.     if ((ret = ff_formats_ref(formats, &outlink->in_formats)) < 0)

  168.         return ret;

  169. 

  170.     return 0;

  171. }

  172. 

  173. static int config_output(AVFilterLink *outlink)

  174. {

  175.     AVFilterContext *ctx = outlink->src;

  176.     AVFilterLink *inlink = ctx->inputs[0];

  177.     ShowSpectrumContext *s = ctx->priv;

  178.     int i, rdft_bits, win_size, h, w;

  179. 

  180.     outlink->w = s->w;

  181.     outlink->h = s->h;

  182. 

  183.     h = (s->mode == COMBINED || s->orientation == HORIZONTAL) ? outlink->h : outlink->h / inlink->channels;

  184.     w = (s->mode == COMBINED || s->orientation == VERTICAL)   ? outlink->w : outlink->w / inlink->channels;

  185.     s->channel_height = h;

  186.     s->channel_width  = w;

  187. 

  188.     if (s->orientation == VERTICAL) {

  189.         /* RDFT window size (precision) according to the requested output frame height */

  190.         for (rdft_bits = 1; 1 << rdft_bits < 2 * h; rdft_bits++);

  191.     } else {

  192.         /* RDFT window size (precision) according to the requested output frame width */

  193.         for (rdft_bits = 1; 1 << rdft_bits < 2 * w; rdft_bits++);

  194.     }

  195.     win_size = 1 << rdft_bits;

  196. 

  197.     /* (re-)configuration if the video output changed (or first init) */

  198.     if (rdft_bits != s->rdft_bits) {

  199.         AVFrame *outpicref;

  200. 

  201.         av_rdft_end(s->rdft);

  202.         s->rdft = av_rdft_init(rdft_bits, DFT_R2C);

  203.         if (!s->rdft) {

  204.             av_log(ctx, AV_LOG_ERROR, "Unable to create RDFT context. "

  205.                    "The window size might be too high.\n");

  206.             return AVERROR(EINVAL);

  207.         }

  208.         s->rdft_bits = rdft_bits;

  209. 

  210.         /* RDFT buffers: x2 for each (display) channel buffer.

  211.          * Note: we use free and malloc instead of a realloc-like function to

  212.          * make sure the buffer is aligned in memory for the FFT functions. */

  213.         for (i = 0; i < s->nb_display_channels; i++)

  214.             av_freep(&s->rdft_data[i]);

  215.         av_freep(&s->rdft_data);

  216.         s->nb_display_channels = inlink->channels;

  217. 

  218.         s->rdft_data = av_calloc(s->nb_display_channels, sizeof(*s->rdft_data));

  219.         if (!s->rdft_data)

  220.             return AVERROR(ENOMEM);

  221.         for (i = 0; i < s->nb_display_channels; i++) {

  222.             s->rdft_data[i] = av_calloc(win_size, sizeof(**s->rdft_data));

  223.             if (!s->rdft_data[i])

  224.                 return AVERROR(ENOMEM);

  225.         }

  226. 

  227.         /* pre-calc windowing function */

  228.         s->window_func_lut =

  229.             av_realloc_f(s->window_func_lut, win_size,

  230.                          sizeof(*s->window_func_lut));

  231.         if (!s->window_func_lut)

  232.             return AVERROR(ENOMEM);

  233.         ff_generate_window_func(s->window_func_lut, win_size, s->win_func, &s->overlap);

  234. 

  235.         for (s->win_scale = 0, i = 0; i < win_size; i++) {

  236.             s->win_scale += s->window_func_lut[i] * s->window_func_lut[i];

  237.         }

  238.         s->win_scale = 1. / (sqrt(s->win_scale) * 32768.);

  239. 

  240.         /* prepare the initial picref buffer (black frame) */

  241.         av_frame_free(&s->outpicref);

  242.         s->outpicref = outpicref =

  243.             ff_get_video_buffer(outlink, outlink->w, outlink->h);

  244.         if (!outpicref)

  245.             return AVERROR(ENOMEM);

  246.         outlink->sample_aspect_ratio = (AVRational){1,1};

  247.         for (i = 0; i < outlink->h; i++) {

  248.             memset(outpicref->data[0] + i * outpicref->linesize[0],   0, outlink->w);

  249.             memset(outpicref->data[1] + i * outpicref->linesize[1], 128, outlink->w);

  250.             memset(outpicref->data[2] + i * outpicref->linesize[2], 128, outlink->w);

  251.         }

  252.     }

  253. 

  254.     if ((s->orientation == VERTICAL   && s->xpos >= outlink->w) ||

  255.         (s->orientation == HORIZONTAL && s->xpos >= outlink->h))

  256.         s->xpos = 0;

  257. 

  258.     outlink->frame_rate = av_make_q(inlink->sample_rate, win_size);

  259.     if (s->orientation == VERTICAL && s->sliding == FULLFRAME)

  260.         outlink->frame_rate.den *= outlink->w;

  261.     if (s->orientation == HORIZONTAL && s->sliding == FULLFRAME)

  262.         outlink->frame_rate.den *= outlink->h;

  263. 

  264.     inlink->min_samples = inlink->max_samples = inlink->partial_buf_size =

  265.         win_size;

  266. 

  267.     if (s->orientation == VERTICAL) {

  268.         s->combine_buffer =

  269.             av_realloc_f(s->combine_buffer, outlink->h * 3,

  270.                          sizeof(*s->combine_buffer));

  271.     } else {

  272.         s->combine_buffer =

  273.             av_realloc_f(s->combine_buffer, outlink->w * 3,

  274.                          sizeof(*s->combine_buffer));

  275.     }

  276. 

  277.     av_log(ctx, AV_LOG_VERBOSE, "s:%dx%d RDFT window size:%d\n",

  278.            s->w, s->h, win_size);

  279.     return 0;

  280. }

  281. 

  282. static int request_frame(AVFilterLink *outlink)

  283. {

  284.     ShowSpectrumContext *s = outlink->src->priv;

  285.     AVFilterLink *inlink = outlink->src->inputs[0];

  286.     unsigned i;

  287.     int ret;

  288. 

  289.     ret = ff_request_frame(inlink);

  290.     if (ret == AVERROR_EOF && s->sliding == FULLFRAME && s->xpos > 0 &&

  291.         s->outpicref) {

  292.         if (s->orientation == VERTICAL) {

  293.             for (i = 0; i < outlink->h; i++) {

  294.                 memset(s->outpicref->data[0] + i * s->outpicref->linesize[0] + s->xpos,   0, outlink->w - s->xpos);

  295.                 memset(s->outpicref->data[1] + i * s->outpicref->linesize[1] + s->xpos, 128, outlink->w - s->xpos);

  296.                 memset(s->outpicref->data[2] + i * s->outpicref->linesize[2] + s->xpos, 128, outlink->w - s->xpos);

  297.             }

  298.         } else {

  299.             for (i = s->xpos; i < outlink->h; i++) {

  300.                 memset(s->outpicref->data[0] + i * s->outpicref->linesize[0],   0, outlink->w);

  301.                 memset(s->outpicref->data[1] + i * s->outpicref->linesize[1], 128, outlink->w);

  302.                 memset(s->outpicref->data[2] + i * s->outpicref->linesize[2], 128, outlink->w);

  303.             }

  304.         }

  305.         ret = ff_filter_frame(outlink, s->outpicref);

  306.         s->outpicref = NULL;

  307.     }

  308. 

  309.     return ret;

  310. }

  311. 

  312. static int plot_spectrum_column(AVFilterLink *inlink, AVFrame *insamples)

  313. {

  314.     int ret;

  315.     AVFilterContext *ctx = inlink->dst;

  316.     AVFilterLink *outlink = ctx->outputs[0];

  317.     ShowSpectrumContext *s = ctx->priv;

  318.     AVFrame *outpicref = s->outpicref;

  319. 

  320.     /* nb_freq contains the power of two superior or equal to the output image

  321.      * height (or half the RDFT window size) */

  322.     const int nb_freq = 1 << (s->rdft_bits - 1);

  323.     const int win_size = nb_freq << 1;

  324.     const double w = s->win_scale;

  325.     int h = s->orientation == VERTICAL ? s->channel_height : s->channel_width;

  326. 

  327.     int ch, plane, n, x, y;

  328. 

  329.     av_assert0(insamples->nb_samples == win_size);

  330. 

  331.     /* fill RDFT input with the number of samples available */

  332.     for (ch = 0; ch < s->nb_display_channels; ch++) {

  333.         const int16_t *p = (int16_t *)insamples->extended_data[ch];

  334. 

  335.         for (n = 0; n < win_size; n++)

  336.             s->rdft_data[ch][n] = p[n] * s->window_func_lut[n];

  337.     }

  338. 

  339.     /* run RDFT on each samples set */

  340.     for (ch = 0; ch < s->nb_display_channels; ch++)

  341.         av_rdft_calc(s->rdft, s->rdft_data[ch]);

  342. 

  343.     /* fill a new spectrum column */

  344. #define RE(y, ch) s->rdft_data[ch][2 * (y) + 0]

  345. #define IM(y, ch) s->rdft_data[ch][2 * (y) + 1]

  346. #define MAGNITUDE(y, ch) hypot(RE(y, ch), IM(y, ch))

  347. 

  348.     /* initialize buffer for combining to black */

  349.     if (s->orientation == VERTICAL) {

  350.         for (y = 0; y < outlink->h; y++) {

  351.             s->combine_buffer[3 * y    ] = 0;

  352.             s->combine_buffer[3 * y + 1] = 127.5;

  353.             s->combine_buffer[3 * y + 2] = 127.5;

  354.         }

  355.     } else {

  356.         for (y = 0; y < outlink->w; y++) {

  357.             s->combine_buffer[3 * y    ] = 0;

  358.             s->combine_buffer[3 * y + 1] = 127.5;

  359.             s->combine_buffer[3 * y + 2] = 127.5;

  360.         }

  361.     }

  362. 

  363.     for (ch = 0; ch < s->nb_display_channels; ch++) {

  364.         float yf, uf, vf;

  365. 

  366.         /* decide color range */

  367.         switch (s->mode) {

  368.         case COMBINED:

  369.             // reduce range by channel count

  370.             yf = 256.0f / s->nb_display_channels;

  371.             switch (s->color_mode) {

  372.             case INTENSITY:

  373.                 uf = yf;

  374.                 vf = yf;

  375.                 break;

  376.             case CHANNEL:

  377.                 /* adjust saturation for mixed UV coloring */

  378.                 /* this factor is correct for infinite channels, an approximation otherwise */

  379.                 uf = yf * M_PI;

  380.                 vf = yf * M_PI;

  381.                 break;

  382.             default:

  383.                 av_assert0(0);

  384.             }

  385.             break;

  386.         case SEPARATE:

  387.             // full range

  388.             yf = 256.0f;

  389.             uf = 256.0f;

  390.             vf = 256.0f;

  391.             break;

  392.         default:

  393.             av_assert0(0);

  394.         }

  395. 

  396.         if (s->color_mode == CHANNEL) {

  397.             if (s->nb_display_channels > 1) {

  398.                 uf *= 0.5 * sin((2 * M_PI * ch) / s->nb_display_channels);

  399.                 vf *= 0.5 * cos((2 * M_PI * ch) / s->nb_display_channels);

  400.             } else {

  401.                 uf = 0.0f;

  402.                 vf = 0.0f;

  403.             }

  404.         }

  405.         uf *= s->saturation;

  406.         vf *= s->saturation;

  407. 

  408.         /* draw the channel */

  409.         for (y = 0; y < h; y++) {

  410.             int row = (s->mode == COMBINED) ? y : ch * h + y;

  411.             float *out = &s->combine_buffer[3 * row];

  412. 

  413.             /* get magnitude */

  414.             float a = w * MAGNITUDE(y, ch);

  415. 

  416.             /* apply scale */

  417.             switch (s->scale) {

  418.             case LINEAR:

  419.                 break;

  420.             case SQRT:

  421.                 a = sqrt(a);

  422.                 break;

  423.             case CBRT:

  424.                 a = cbrt(a);

  425.                 break;

  426.             case LOG:

  427.                 a = 1 + log10(FFMAX(FFMIN(1, a), 1e-6)) / 5; // zero = -120dBFS

  428.                 break;

  429.             default:

  430.                 av_assert0(0);

  431.             }

  432. 

  433.             if (s->color_mode == INTENSITY) {

  434.                 float y, u, v;

  435.                 int i;

  436. 

  437.                 for (i = 1; i < FF_ARRAY_ELEMS(intensity_color_table) - 1; i++)

  438.                     if (intensity_color_table[i].a >= a)

  439.                         break;

  440.                 // i now is the first item >= the color

  441.                 // now we know to interpolate between item i - 1 and i

  442.                 if (a <= intensity_color_table[i - 1].a) {

  443.                     y = intensity_color_table[i - 1].y;

  444.                     u = intensity_color_table[i - 1].u;

  445.                     v = intensity_color_table[i - 1].v;

  446.                 } else if (a >= intensity_color_table[i].a) {

  447.                     y = intensity_color_table[i].y;

  448.                     u = intensity_color_table[i].u;

  449.                     v = intensity_color_table[i].v;

  450.                 } else {

  451.                     float start = intensity_color_table[i - 1].a;

  452.                     float end = intensity_color_table[i].a;

  453.                     float lerpfrac = (a - start) / (end - start);

  454.                     y = intensity_color_table[i - 1].y * (1.0f - lerpfrac)

  455.                       + intensity_color_table[i].y * lerpfrac;

  456.                     u = intensity_color_table[i - 1].u * (1.0f - lerpfrac)

  457.                       + intensity_color_table[i].u * lerpfrac;

  458.                     v = intensity_color_table[i - 1].v * (1.0f - lerpfrac)

  459.                       + intensity_color_table[i].v * lerpfrac;

  460.                 }

  461. 

  462.                 out[0] += y * yf;

  463.                 out[1] += u * uf;

  464.                 out[2] += v * vf;

  465.             } else {

  466.                 out[0] += a * yf;

  467.                 out[1] += a * uf;

  468.                 out[2] += a * vf;

  469.             }

  470.         }

  471.     }

  472. 

  473.     /* copy to output */

  474.     if (s->orientation == VERTICAL) {

  475.         if (s->sliding == SCROLL) {

  476.             for (plane = 0; plane < 3; plane++) {

  477.                 for (y = 0; y < outlink->h; y++) {

  478.                     uint8_t *p = outpicref->data[plane] +

  479.                                  y * outpicref->linesize[plane];

  480.                     memmove(p, p + 1, outlink->w - 1);

  481.                 }

  482.             }

  483.             s->xpos = outlink->w - 1;

  484.         } else if (s->sliding == RSCROLL) {

  485.             for (plane = 0; plane < 3; plane++) {

  486.                 for (y = 0; y < outlink->h; y++) {

  487.                     uint8_t *p = outpicref->data[plane] +

  488.                                  y * outpicref->linesize[plane];

  489.                     memmove(p + 1, p, outlink->w - 1);

  490.                 }

  491.             }

  492.             s->xpos = 0;

  493.         }

  494.         for (plane = 0; plane < 3; plane++) {

  495.             uint8_t *p = outpicref->data[plane] +

  496.                          (outlink->h - 1) * outpicref->linesize[plane] +

  497.                          s->xpos;

  498.             for (y = 0; y < outlink->h; y++) {

  499.                 *p = lrint(FFMAX(0, FFMIN(s->combine_buffer[3 * y + plane], 255)));

  500.                 p -= outpicref->linesize[plane];

  501.             }

  502.         }

  503.     } else {

  504.         if (s->sliding == SCROLL) {

  505.             for (plane = 0; plane < 3; plane++) {

  506.                 for (y = 1; y < outlink->h; y++) {

  507.                     memmove(outpicref->data[plane] + (y-1) * outpicref->linesize[plane],

  508.                             outpicref->data[plane] + (y  ) * outpicref->linesize[plane],

  509.                             outlink->w);

  510.                 }

  511.             }

  512.             s->xpos = outlink->h - 1;

  513.         } else if (s->sliding == RSCROLL) {

  514.             for (plane = 0; plane < 3; plane++) {

  515.                 for (y = outlink->h - 1; y >= 1; y--) {

  516.                     memmove(outpicref->data[plane] + (y  ) * outpicref->linesize[plane],

  517.                             outpicref->data[plane] + (y-1) * outpicref->linesize[plane],

  518.                             outlink->w);

  519.                 }

  520.             }

  521.             s->xpos = 0;

  522.         }

  523.         for (plane = 0; plane < 3; plane++) {

  524.             uint8_t *p = outpicref->data[plane] +

  525.                          s->xpos * outpicref->linesize[plane];

  526.             for (x = 0; x < outlink->w; x++) {

  527.                 *p = lrint(FFMAX(0, FFMIN(s->combine_buffer[3 * x + plane], 255)));

  528.                 p++;

  529.             }

  530.         }

  531.     }

  532. 

  533.     if (s->sliding != FULLFRAME || s->xpos == 0)

  534.         outpicref->pts = insamples->pts;

  535. 

  536.     s->xpos++;

  537.     if (s->orientation == VERTICAL && s->xpos >= outlink->w)

  538.         s->xpos = 0;

  539.     if (s->orientation == HORIZONTAL && s->xpos >= outlink->h)

  540.         s->xpos = 0;

  541.     if (s->sliding != FULLFRAME || s->xpos == 0) {

  542.         ret = ff_filter_frame(outlink, av_frame_clone(s->outpicref));

  543.         if (ret < 0)

  544.             return ret;

  545.     }

  546. 

  547.     return win_size;

  548. }

  549. 

  550. static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)

  551. {

  552.     AVFilterContext *ctx = inlink->dst;

  553.     ShowSpectrumContext *s = ctx->priv;

  554.     unsigned win_size = 1 << s->rdft_bits;

  555.     int ret = 0;

  556. 

  557.     av_assert0(insamples->nb_samples <= win_size);

  558.     if (insamples->nb_samples == win_size)

  559.         ret = plot_spectrum_column(inlink, insamples);

  560. 

  561.     av_frame_free(&insamples);

  562.     return ret;

  563. }

  564. 

  565. static const AVFilterPad showspectrum_inputs[] = {

  566.     {

  567.         .name         = "default",

  568.         .type         = AVMEDIA_TYPE_AUDIO,

  569.         .filter_frame = filter_frame,

  570.     },

  571.     { NULL }

  572. };

  573. 

  574. static const AVFilterPad showspectrum_outputs[] = {

  575.     {

  576.         .name          = "default",

  577.         .type          = AVMEDIA_TYPE_VIDEO,

  578.         .config_props  = config_output,

  579.         .request_frame = request_frame,

  580.     },

  581.     { NULL }

  582. };

  583. 

  584. AVFilter ff_avf_showspectrum = {

  585.     .name          = "showspectrum",

  586.     .description   = NULL_IF_CONFIG_SMALL("Convert input audio to a spectrum video output."),

  587.     .uninit        = uninit,

  588.     .query_formats = query_formats,

  589.     .priv_size     = sizeof(ShowSpectrumContext),

  590.     .inputs        = showspectrum_inputs,

  591.     .outputs       = showspectrum_outputs,

  592.     .priv_class    = &showspectrum_class,

  593. };