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  1. /*
  2.  * Copyright (c) 2012 Clément Bœsch
  3.  *
  4.  * This file is part of FFmpeg.
  5.  *
  6.  * FFmpeg is free software; you can redistribute it and/or modify
  7.  * it under the terms of the GNU General Public License as published by
  8.  * the Free Software Foundation; either version 2 of the License, or
  9.  * (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
  14.  * GNU General Public License for more details.
  15.  *
  16.  * You should have received a copy of the GNU General Public License along
  17.  * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
  18.  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19.  */
  20.  
  21. /**
  22.  * @file
  23.  * EBU R.128 implementation
  24.  * @see http://tech.ebu.ch/loudness
  25.  * @see https://www.youtube.com/watch?v=iuEtQqC-Sqo "EBU R128 Introduction - Florian Camerer"
  26.  * @todo True Peak
  27.  * @todo implement start/stop/reset through filter command injection
  28.  * @todo support other frequencies to avoid resampling
  29.  */
  30.  
  31. #include <math.h>
  32.  
  33. #include "libavutil/avassert.h"
  34. #include "libavutil/avstring.h"
  35. #include "libavutil/channel_layout.h"
  36. #include "libavutil/dict.h"
  37. #include "libavutil/xga_font_data.h"
  38. #include "libavutil/opt.h"
  39. #include "libavutil/timestamp.h"
  40. #include "audio.h"
  41. #include "avfilter.h"
  42. #include "formats.h"
  43. #include "internal.h"
  44.  
  45. #define MAX_CHANNELS 63
  46.  
  47. /* pre-filter coefficients */
  48. #define PRE_B0  1.53512485958697
  49. #define PRE_B1 -2.69169618940638
  50. #define PRE_B2  1.19839281085285
  51. #define PRE_A1 -1.69065929318241
  52. #define PRE_A2  0.73248077421585
  53.  
  54. /* RLB-filter coefficients */
  55. #define RLB_B0  1.0
  56. #define RLB_B1 -2.0
  57. #define RLB_B2  1.0
  58. #define RLB_A1 -1.99004745483398
  59. #define RLB_A2  0.99007225036621
  60.  
  61. #define ABS_THRES    -70            ///< silence gate: we discard anything below this absolute (LUFS) threshold
  62. #define ABS_UP_THRES  10            ///< upper loud limit to consider (ABS_THRES being the minimum)
  63. #define HIST_GRAIN   100            ///< defines histogram precision
  64. #define HIST_SIZE  ((ABS_UP_THRES - ABS_THRES) * HIST_GRAIN + 1)
  65.  
  66. /**
  67.  * A histogram is an array of HIST_SIZE hist_entry storing all the energies
  68.  * recorded (with an accuracy of 1/HIST_GRAIN) of the loudnesses from ABS_THRES
  69.  * (at 0) to ABS_UP_THRES (at HIST_SIZE-1).
  70.  * This fixed-size system avoids the need of a list of energies growing
  71.  * infinitely over the time and is thus more scalable.
  72.  */
  73. struct hist_entry {
  74.     int count;                      ///< how many times the corresponding value occurred
  75.     double energy;                  ///< E = 10^((L + 0.691) / 10)
  76.     double loudness;                ///< L = -0.691 + 10 * log10(E)
  77. };
  78.  
  79. struct integrator {
  80.     double *cache[MAX_CHANNELS];    ///< window of filtered samples (N ms)
  81.     int cache_pos;                  ///< focus on the last added bin in the cache array
  82.     double sum[MAX_CHANNELS];       ///< sum of the last N ms filtered samples (cache content)
  83.     int filled;                     ///< 1 if the cache is completely filled, 0 otherwise
  84.     double rel_threshold;           ///< relative threshold
  85.     double sum_kept_powers;         ///< sum of the powers (weighted sums) above absolute threshold
  86.     int nb_kept_powers;             ///< number of sum above absolute threshold
  87.     struct hist_entry *histogram;   ///< histogram of the powers, used to compute LRA and I
  88. };
  89.  
  90. struct rect { int x, y, w, h; };
  91.  
  92. typedef struct {
  93.     const AVClass *class;           ///< AVClass context for log and options purpose
  94.  
  95.     /* video  */
  96.     int do_video;                   ///< 1 if video output enabled, 0 otherwise
  97.     int w, h;                       ///< size of the video output
  98.     struct rect text;               ///< rectangle for the LU legend on the left
  99.     struct rect graph;              ///< rectangle for the main graph in the center
  100.     struct rect gauge;              ///< rectangle for the gauge on the right
  101.     AVFrame *outpicref;             ///< output picture reference, updated regularly
  102.     int meter;                      ///< select a EBU mode between +9 and +18
  103.     int scale_range;                ///< the range of LU values according to the meter
  104.     int y_zero_lu;                  ///< the y value (pixel position) for 0 LU
  105.     int *y_line_ref;                ///< y reference values for drawing the LU lines in the graph and the gauge
  106.  
  107.     /* audio */
  108.     int nb_channels;                ///< number of channels in the input
  109.     double *ch_weighting;           ///< channel weighting mapping
  110.     int sample_count;               ///< sample count used for refresh frequency, reset at refresh
  111.  
  112.     /* Filter caches.
  113.      * The mult by 3 in the following is for X[i], X[i-1] and X[i-2] */
  114.     double x[MAX_CHANNELS * 3];     ///< 3 input samples cache for each channel
  115.     double y[MAX_CHANNELS * 3];     ///< 3 pre-filter samples cache for each channel
  116.     double z[MAX_CHANNELS * 3];     ///< 3 RLB-filter samples cache for each channel
  117.  
  118. #define I400_BINS  (48000 * 4 / 10)
  119. #define I3000_BINS (48000 * 3)
  120.     struct integrator i400;         ///< 400ms integrator, used for Momentary loudness  (M), and Integrated loudness (I)
  121.     struct integrator i3000;        ///<    3s integrator, used for Short term loudness (S), and Loudness Range      (LRA)
  122.  
  123.     /* I and LRA specific */
  124.     double integrated_loudness;     ///< integrated loudness in LUFS (I)
  125.     double loudness_range;          ///< loudness range in LU (LRA)
  126.     double lra_low, lra_high;       ///< low and high LRA values
  127.  
  128.     /* misc */
  129.     int loglevel;                   ///< log level for frame logging
  130.     int metadata;                   ///< whether or not to inject loudness results in frames
  131. } EBUR128Context;
  132.  
  133. #define OFFSET(x) offsetof(EBUR128Context, x)
  134. #define A AV_OPT_FLAG_AUDIO_PARAM
  135. #define V AV_OPT_FLAG_VIDEO_PARAM
  136. #define F AV_OPT_FLAG_FILTERING_PARAM
  137. static const AVOption ebur128_options[] = {
  138.     { "video", "set video output", OFFSET(do_video), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, V|F },
  139.     { "size",  "set video size",   OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "640x480"}, 0, 0, V|F },
  140.     { "meter", "set scale meter (+9 to +18)",  OFFSET(meter), AV_OPT_TYPE_INT, {.i64 = 9}, 9, 18, V|F },
  141.     { "framelog", "force frame logging level", OFFSET(loglevel), AV_OPT_TYPE_INT, {.i64 = -1},   INT_MIN, INT_MAX, A|V|F, "level" },
  142.         { "info",    "information logging level", 0, AV_OPT_TYPE_CONST, {.i64 = AV_LOG_INFO},    INT_MIN, INT_MAX, A|V|F, "level" },
  143.         { "verbose", "verbose logging level",     0, AV_OPT_TYPE_CONST, {.i64 = AV_LOG_VERBOSE}, INT_MIN, INT_MAX, A|V|F, "level" },
  144.     { "metadata", "inject metadata in the filtergraph", OFFSET(metadata), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, A|V|F },
  145.     { NULL }
  146. };
  147.  
  148. AVFILTER_DEFINE_CLASS(ebur128);
  149.  
  150. static const uint8_t graph_colors[] = {
  151.     0xdd, 0x66, 0x66,   // value above 0LU non reached
  152.     0x66, 0x66, 0xdd,   // value below 0LU non reached
  153.     0x96, 0x33, 0x33,   // value above 0LU reached
  154.     0x33, 0x33, 0x96,   // value below 0LU reached
  155.     0xdd, 0x96, 0x96,   // value above 0LU line non reached
  156.     0x96, 0x96, 0xdd,   // value below 0LU line non reached
  157.     0xdd, 0x33, 0x33,   // value above 0LU line reached
  158.     0x33, 0x33, 0xdd,   // value below 0LU line reached
  159. };
  160.  
  161. static const uint8_t *get_graph_color(const EBUR128Context *ebur128, int v, int y)
  162. {
  163.     const int below0  = y > ebur128->y_zero_lu;
  164.     const int reached = y >= v;
  165.     const int line    = ebur128->y_line_ref[y] || y == ebur128->y_zero_lu;
  166.     const int colorid = 4*line + 2*reached + below0;
  167.     return graph_colors + 3*colorid;
  168. }
  169.  
  170. static inline int lu_to_y(const EBUR128Context *ebur128, double v)
  171. {
  172.     v += 2 * ebur128->meter;                            // make it in range [0;...]
  173.     v  = av_clipf(v, 0, ebur128->scale_range);          // make sure it's in the graph scale
  174.     v  = ebur128->scale_range - v;                      // invert value (y=0 is on top)
  175.     return v * ebur128->graph.h / ebur128->scale_range; // rescale from scale range to px height
  176. }
  177.  
  178. #define FONT8   0
  179. #define FONT16  1
  180.  
  181. static const uint8_t font_colors[] = {
  182.     0xdd, 0xdd, 0x00,
  183.     0x00, 0x96, 0x96,
  184. };
  185.  
  186. static void drawtext(AVFrame *pic, int x, int y, int ftid, const uint8_t *color, const char *fmt, ...)
  187. {
  188.     int i;
  189.     char buf[128] = {0};
  190.     const uint8_t *font;
  191.     int font_height;
  192.     va_list vl;
  193.  
  194.     if      (ftid == FONT16) font = avpriv_vga16_font, font_height = 16;
  195.     else if (ftid == FONT8)  font = avpriv_cga_font,   font_height =  8;
  196.     else return;
  197.  
  198.     va_start(vl, fmt);
  199.     vsnprintf(buf, sizeof(buf), fmt, vl);
  200.     va_end(vl);
  201.  
  202.     for (i = 0; buf[i]; i++) {
  203.         int char_y, mask;
  204.         uint8_t *p = pic->data[0] + y*pic->linesize[0] + (x + i*8)*3;
  205.  
  206.         for (char_y = 0; char_y < font_height; char_y++) {
  207.             for (mask = 0x80; mask; mask >>= 1) {
  208.                 if (font[buf[i] * font_height + char_y] & mask)
  209.                     memcpy(p, color, 3);
  210.                 else
  211.                     memcpy(p, "\x00\x00\x00", 3);
  212.                 p += 3;
  213.             }
  214.             p += pic->linesize[0] - 8*3;
  215.         }
  216.     }
  217. }
  218.  
  219. static void drawline(AVFrame *pic, int x, int y, int len, int step)
  220. {
  221.     int i;
  222.     uint8_t *p = pic->data[0] + y*pic->linesize[0] + x*3;
  223.  
  224.     for (i = 0; i < len; i++) {
  225.         memcpy(p, "\x00\xff\x00", 3);
  226.         p += step;
  227.     }
  228. }
  229.  
  230. static int config_video_output(AVFilterLink *outlink)
  231. {
  232.     int i, x, y;
  233.     uint8_t *p;
  234.     AVFilterContext *ctx = outlink->src;
  235.     EBUR128Context *ebur128 = ctx->priv;
  236.     AVFrame *outpicref;
  237.  
  238.     /* check if there is enough space to represent everything decently */
  239.     if (ebur128->w < 640 || ebur128->h < 480) {
  240.         av_log(ctx, AV_LOG_ERROR, "Video size %dx%d is too small, "
  241.                "minimum size is 640x480\n", ebur128->w, ebur128->h);
  242.         return AVERROR(EINVAL);
  243.     }
  244.     outlink->w = ebur128->w;
  245.     outlink->h = ebur128->h;
  246.  
  247. #define PAD 8
  248.  
  249.     /* configure text area position and size */
  250.     ebur128->text.x  = PAD;
  251.     ebur128->text.y  = 40;
  252.     ebur128->text.w  = 3 * 8;   // 3 characters
  253.     ebur128->text.h  = ebur128->h - PAD - ebur128->text.y;
  254.  
  255.     /* configure gauge position and size */
  256.     ebur128->gauge.w = 20;
  257.     ebur128->gauge.h = ebur128->text.h;
  258.     ebur128->gauge.x = ebur128->w - PAD - ebur128->gauge.w;
  259.     ebur128->gauge.y = ebur128->text.y;
  260.  
  261.     /* configure graph position and size */
  262.     ebur128->graph.x = ebur128->text.x + ebur128->text.w + PAD;
  263.     ebur128->graph.y = ebur128->gauge.y;
  264.     ebur128->graph.w = ebur128->gauge.x - ebur128->graph.x - PAD;
  265.     ebur128->graph.h = ebur128->gauge.h;
  266.  
  267.     /* graph and gauge share the LU-to-pixel code */
  268.     av_assert0(ebur128->graph.h == ebur128->gauge.h);
  269.  
  270.     /* prepare the initial picref buffer */
  271.     av_frame_free(&ebur128->outpicref);
  272.     ebur128->outpicref = outpicref =
  273.         ff_get_video_buffer(outlink, outlink->w, outlink->h);
  274.     if (!outpicref)
  275.         return AVERROR(ENOMEM);
  276.     outlink->sample_aspect_ratio = (AVRational){1,1};
  277.  
  278.     /* init y references values (to draw LU lines) */
  279.     ebur128->y_line_ref = av_calloc(ebur128->graph.h + 1, sizeof(*ebur128->y_line_ref));
  280.     if (!ebur128->y_line_ref)
  281.         return AVERROR(ENOMEM);
  282.  
  283.     /* black background */
  284.     memset(outpicref->data[0], 0, ebur128->h * outpicref->linesize[0]);
  285.  
  286.     /* draw LU legends */
  287.     drawtext(outpicref, PAD, PAD+16, FONT8, font_colors+3, " LU");
  288.     for (i = ebur128->meter; i >= -ebur128->meter * 2; i--) {
  289.         y = lu_to_y(ebur128, i);
  290.         x = PAD + (i < 10 && i > -10) * 8;
  291.         ebur128->y_line_ref[y] = i;
  292.         y -= 4; // -4 to center vertically
  293.         drawtext(outpicref, x, y + ebur128->graph.y, FONT8, font_colors+3,
  294.                  "%c%d", i < 0 ? '-' : i > 0 ? '+' : ' ', FFABS(i));
  295.     }
  296.  
  297.     /* draw graph */
  298.     ebur128->y_zero_lu = lu_to_y(ebur128, 0);
  299.     p = outpicref->data[0] + ebur128->graph.y * outpicref->linesize[0]
  300.                            + ebur128->graph.x * 3;
  301.     for (y = 0; y < ebur128->graph.h; y++) {
  302.         const uint8_t *c = get_graph_color(ebur128, INT_MAX, y);
  303.  
  304.         for (x = 0; x < ebur128->graph.w; x++)
  305.             memcpy(p + x*3, c, 3);
  306.         p += outpicref->linesize[0];
  307.     }
  308.  
  309.     /* draw fancy rectangles around the graph and the gauge */
  310. #define DRAW_RECT(r) do { \
  311.     drawline(outpicref, r.x,       r.y - 1,   r.w, 3); \
  312.     drawline(outpicref, r.x,       r.y + r.h, r.w, 3); \
  313.     drawline(outpicref, r.x - 1,   r.y,       r.h, outpicref->linesize[0]); \
  314.     drawline(outpicref, r.x + r.w, r.y,       r.h, outpicref->linesize[0]); \
  315. } while (0)
  316.     DRAW_RECT(ebur128->graph);
  317.     DRAW_RECT(ebur128->gauge);
  318.  
  319.     outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
  320.  
  321.     return 0;
  322. }
  323.  
  324. static int config_audio_input(AVFilterLink *inlink)
  325. {
  326.     AVFilterContext *ctx = inlink->dst;
  327.     EBUR128Context *ebur128 = ctx->priv;
  328.  
  329.     /* force 100ms framing in case of metadata injection: the frames must have
  330.      * a granularity of the window overlap to be accurately exploited */
  331.     if (ebur128->metadata)
  332.         inlink->min_samples =
  333.         inlink->max_samples =
  334.         inlink->partial_buf_size = inlink->sample_rate / 10;
  335.     return 0;
  336. }
  337.  
  338. static int config_audio_output(AVFilterLink *outlink)
  339. {
  340.     int i;
  341.     int idx_bitposn = 0;
  342.     AVFilterContext *ctx = outlink->src;
  343.     EBUR128Context *ebur128 = ctx->priv;
  344.     const int nb_channels = av_get_channel_layout_nb_channels(outlink->channel_layout);
  345.  
  346. #define BACK_MASK (AV_CH_BACK_LEFT    |AV_CH_BACK_CENTER    |AV_CH_BACK_RIGHT| \
  347.                    AV_CH_TOP_BACK_LEFT|AV_CH_TOP_BACK_CENTER|AV_CH_TOP_BACK_RIGHT| \
  348.                    AV_CH_SIDE_LEFT                          |AV_CH_SIDE_RIGHT| \
  349.                    AV_CH_SURROUND_DIRECT_LEFT               |AV_CH_SURROUND_DIRECT_RIGHT)
  350.  
  351.     ebur128->nb_channels  = nb_channels;
  352.     ebur128->ch_weighting = av_calloc(nb_channels, sizeof(*ebur128->ch_weighting));
  353.     if (!ebur128->ch_weighting)
  354.         return AVERROR(ENOMEM);
  355.  
  356.     for (i = 0; i < nb_channels; i++) {
  357.  
  358.         /* find the next bit that is set starting from the right */
  359.         while ((outlink->channel_layout & 1ULL<<idx_bitposn) == 0 && idx_bitposn < 63)
  360.             idx_bitposn++;
  361.  
  362.         /* channel weighting */
  363.         if ((1ULL<<idx_bitposn & AV_CH_LOW_FREQUENCY) ||
  364.             (1ULL<<idx_bitposn & AV_CH_LOW_FREQUENCY_2)) {
  365.             ebur128->ch_weighting[i] = 0;
  366.         } else if (1ULL<<idx_bitposn & BACK_MASK) {
  367.             ebur128->ch_weighting[i] = 1.41;
  368.         } else {
  369.             ebur128->ch_weighting[i] = 1.0;
  370.         }
  371.  
  372.         idx_bitposn++;
  373.  
  374.         if (!ebur128->ch_weighting[i])
  375.             continue;
  376.  
  377.         /* bins buffer for the two integration window (400ms and 3s) */
  378.         ebur128->i400.cache[i]  = av_calloc(I400_BINS,  sizeof(*ebur128->i400.cache[0]));
  379.         ebur128->i3000.cache[i] = av_calloc(I3000_BINS, sizeof(*ebur128->i3000.cache[0]));
  380.         if (!ebur128->i400.cache[i] || !ebur128->i3000.cache[i])
  381.             return AVERROR(ENOMEM);
  382.     }
  383.  
  384.     outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
  385.  
  386.     return 0;
  387. }
  388.  
  389. #define ENERGY(loudness) (pow(10, ((loudness) + 0.691) / 10.))
  390. #define LOUDNESS(energy) (-0.691 + 10 * log10(energy))
  391.  
  392. static struct hist_entry *get_histogram(void)
  393. {
  394.     int i;
  395.     struct hist_entry *h = av_calloc(HIST_SIZE, sizeof(*h));
  396.  
  397.     if (!h)
  398.         return NULL;
  399.     for (i = 0; i < HIST_SIZE; i++) {
  400.         h[i].loudness = i / (double)HIST_GRAIN + ABS_THRES;
  401.         h[i].energy   = ENERGY(h[i].loudness);
  402.     }
  403.     return h;
  404. }
  405.  
  406. static av_cold int init(AVFilterContext *ctx)
  407. {
  408.     EBUR128Context *ebur128 = ctx->priv;
  409.     AVFilterPad pad;
  410.  
  411.     if (ebur128->loglevel != AV_LOG_INFO &&
  412.         ebur128->loglevel != AV_LOG_VERBOSE) {
  413.         if (ebur128->do_video || ebur128->metadata)
  414.             ebur128->loglevel = AV_LOG_VERBOSE;
  415.         else
  416.             ebur128->loglevel = AV_LOG_INFO;
  417.     }
  418.  
  419.     // if meter is  +9 scale, scale range is from -18 LU to  +9 LU (or 3*9)
  420.     // if meter is +18 scale, scale range is from -36 LU to +18 LU (or 3*18)
  421.     ebur128->scale_range = 3 * ebur128->meter;
  422.  
  423.     ebur128->i400.histogram  = get_histogram();
  424.     ebur128->i3000.histogram = get_histogram();
  425.     if (!ebur128->i400.histogram || !ebur128->i3000.histogram)
  426.         return AVERROR(ENOMEM);
  427.  
  428.     ebur128->integrated_loudness = ABS_THRES;
  429.     ebur128->loudness_range = 0;
  430.  
  431.     /* insert output pads */
  432.     if (ebur128->do_video) {
  433.         pad = (AVFilterPad){
  434.             .name         = av_strdup("out0"),
  435.             .type         = AVMEDIA_TYPE_VIDEO,
  436.             .config_props = config_video_output,
  437.         };
  438.         if (!pad.name)
  439.             return AVERROR(ENOMEM);
  440.         ff_insert_outpad(ctx, 0, &pad);
  441.     }
  442.     pad = (AVFilterPad){
  443.         .name         = av_asprintf("out%d", ebur128->do_video),
  444.         .type         = AVMEDIA_TYPE_AUDIO,
  445.         .config_props = config_audio_output,
  446.     };
  447.     if (!pad.name)
  448.         return AVERROR(ENOMEM);
  449.     ff_insert_outpad(ctx, ebur128->do_video, &pad);
  450.  
  451.     /* summary */
  452.     av_log(ctx, AV_LOG_VERBOSE, "EBU +%d scale\n", ebur128->meter);
  453.  
  454.     return 0;
  455. }
  456.  
  457. #define HIST_POS(power) (int)(((power) - ABS_THRES) * HIST_GRAIN)
  458.  
  459. /* loudness and power should be set such as loudness = -0.691 +
  460.  * 10*log10(power), we just avoid doing that calculus two times */
  461. static int gate_update(struct integrator *integ, double power,
  462.                        double loudness, int gate_thres)
  463. {
  464.     int ipower;
  465.     double relative_threshold;
  466.     int gate_hist_pos;
  467.  
  468.     /* update powers histograms by incrementing current power count */
  469.     ipower = av_clip(HIST_POS(loudness), 0, HIST_SIZE - 1);
  470.     integ->histogram[ipower].count++;
  471.  
  472.     /* compute relative threshold and get its position in the histogram */
  473.     integ->sum_kept_powers += power;
  474.     integ->nb_kept_powers++;
  475.     relative_threshold = integ->sum_kept_powers / integ->nb_kept_powers;
  476.     if (!relative_threshold)
  477.         relative_threshold = 1e-12;
  478.     integ->rel_threshold = LOUDNESS(relative_threshold) + gate_thres;
  479.     gate_hist_pos = av_clip(HIST_POS(integ->rel_threshold), 0, HIST_SIZE - 1);
  480.  
  481.     return gate_hist_pos;
  482. }
  483.  
  484. static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
  485. {
  486.     int i, ch, idx_insample;
  487.     AVFilterContext *ctx = inlink->dst;
  488.     EBUR128Context *ebur128 = ctx->priv;
  489.     const int nb_channels = ebur128->nb_channels;
  490.     const int nb_samples  = insamples->nb_samples;
  491.     const double *samples = (double *)insamples->data[0];
  492.     AVFrame *pic = ebur128->outpicref;
  493.  
  494.     for (idx_insample = 0; idx_insample < nb_samples; idx_insample++) {
  495.         const int bin_id_400  = ebur128->i400.cache_pos;
  496.         const int bin_id_3000 = ebur128->i3000.cache_pos;
  497.  
  498. #define MOVE_TO_NEXT_CACHED_ENTRY(time) do {                \
  499.     ebur128->i##time.cache_pos++;                           \
  500.     if (ebur128->i##time.cache_pos == I##time##_BINS) {     \
  501.         ebur128->i##time.filled    = 1;                     \
  502.         ebur128->i##time.cache_pos = 0;                     \
  503.     }                                                       \
  504. } while (0)
  505.  
  506.         MOVE_TO_NEXT_CACHED_ENTRY(400);
  507.         MOVE_TO_NEXT_CACHED_ENTRY(3000);
  508.  
  509.         for (ch = 0; ch < nb_channels; ch++) {
  510.             double bin;
  511.  
  512.             ebur128->x[ch * 3] = *samples++; // set X[i]
  513.  
  514.             if (!ebur128->ch_weighting[ch])
  515.                 continue;
  516.  
  517.             /* Y[i] = X[i]*b0 + X[i-1]*b1 + X[i-2]*b2 - Y[i-1]*a1 - Y[i-2]*a2 */
  518. #define FILTER(Y, X, name) do {                                                 \
  519.             double *dst = ebur128->Y + ch*3;                                    \
  520.             double *src = ebur128->X + ch*3;                                    \
  521.             dst[2] = dst[1];                                                    \
  522.             dst[1] = dst[0];                                                    \
  523.             dst[0] = src[0]*name##_B0 + src[1]*name##_B1 + src[2]*name##_B2     \
  524.                                       - dst[1]*name##_A1 - dst[2]*name##_A2;    \
  525. } while (0)
  526.  
  527.             // TODO: merge both filters in one?
  528.             FILTER(y, x, PRE);  // apply pre-filter
  529.             ebur128->x[ch * 3 + 2] = ebur128->x[ch * 3 + 1];
  530.             ebur128->x[ch * 3 + 1] = ebur128->x[ch * 3    ];
  531.             FILTER(z, y, RLB);  // apply RLB-filter
  532.  
  533.             bin = ebur128->z[ch * 3] * ebur128->z[ch * 3];
  534.  
  535.             /* add the new value, and limit the sum to the cache size (400ms or 3s)
  536.              * by removing the oldest one */
  537.             ebur128->i400.sum [ch] = ebur128->i400.sum [ch] + bin - ebur128->i400.cache [ch][bin_id_400];
  538.             ebur128->i3000.sum[ch] = ebur128->i3000.sum[ch] + bin - ebur128->i3000.cache[ch][bin_id_3000];
  539.  
  540.             /* override old cache entry with the new value */
  541.             ebur128->i400.cache [ch][bin_id_400 ] = bin;
  542.             ebur128->i3000.cache[ch][bin_id_3000] = bin;
  543.         }
  544.  
  545.         /* For integrated loudness, gating blocks are 400ms long with 75%
  546.          * overlap (see BS.1770-2 p5), so a re-computation is needed each 100ms
  547.          * (4800 samples at 48kHz). */
  548.         if (++ebur128->sample_count == 4800) {
  549.             double loudness_400, loudness_3000;
  550.             double power_400 = 1e-12, power_3000 = 1e-12;
  551.             AVFilterLink *outlink = ctx->outputs[0];
  552.             const int64_t pts = insamples->pts +
  553.                 av_rescale_q(idx_insample, (AVRational){ 1, inlink->sample_rate },
  554.                              outlink->time_base);
  555.  
  556.             ebur128->sample_count = 0;
  557.  
  558. #define COMPUTE_LOUDNESS(m, time) do {                                              \
  559.     if (ebur128->i##time.filled) {                                                  \
  560.         /* weighting sum of the last <time> ms */                                   \
  561.         for (ch = 0; ch < nb_channels; ch++)                                        \
  562.             power_##time += ebur128->ch_weighting[ch] * ebur128->i##time.sum[ch];   \
  563.         power_##time /= I##time##_BINS;                                             \
  564.     }                                                                               \
  565.     loudness_##time = LOUDNESS(power_##time);                                       \
  566. } while (0)
  567.  
  568.             COMPUTE_LOUDNESS(M,  400);
  569.             COMPUTE_LOUDNESS(S, 3000);
  570.  
  571.             /* Integrated loudness */
  572. #define I_GATE_THRES -10  // initially defined to -8 LU in the first EBU standard
  573.  
  574.             if (loudness_400 >= ABS_THRES) {
  575.                 double integrated_sum = 0;
  576.                 int nb_integrated = 0;
  577.                 int gate_hist_pos = gate_update(&ebur128->i400, power_400,
  578.                                                 loudness_400, I_GATE_THRES);
  579.  
  580.                 /* compute integrated loudness by summing the histogram values
  581.                  * above the relative threshold */
  582.                 for (i = gate_hist_pos; i < HIST_SIZE; i++) {
  583.                     const int nb_v = ebur128->i400.histogram[i].count;
  584.                     nb_integrated  += nb_v;
  585.                     integrated_sum += nb_v * ebur128->i400.histogram[i].energy;
  586.                 }
  587.                 if (nb_integrated)
  588.                     ebur128->integrated_loudness = LOUDNESS(integrated_sum / nb_integrated);
  589.             }
  590.  
  591.             /* LRA */
  592. #define LRA_GATE_THRES -20
  593. #define LRA_LOWER_PRC   10
  594. #define LRA_HIGHER_PRC  95
  595.  
  596.             /* XXX: example code in EBU 3342 is ">=" but formula in BS.1770
  597.              * specs is ">" */
  598.             if (loudness_3000 >= ABS_THRES) {
  599.                 int nb_powers = 0;
  600.                 int gate_hist_pos = gate_update(&ebur128->i3000, power_3000,
  601.                                                 loudness_3000, LRA_GATE_THRES);
  602.  
  603.                 for (i = gate_hist_pos; i < HIST_SIZE; i++)
  604.                     nb_powers += ebur128->i3000.histogram[i].count;
  605.                 if (nb_powers) {
  606.                     int n, nb_pow;
  607.  
  608.                     /* get lower loudness to consider */
  609.                     n = 0;
  610.                     nb_pow = LRA_LOWER_PRC  * nb_powers / 100. + 0.5;
  611.                     for (i = gate_hist_pos; i < HIST_SIZE; i++) {
  612.                         n += ebur128->i3000.histogram[i].count;
  613.                         if (n >= nb_pow) {
  614.                             ebur128->lra_low = ebur128->i3000.histogram[i].loudness;
  615.                             break;
  616.                         }
  617.                     }
  618.  
  619.                     /* get higher loudness to consider */
  620.                     n = nb_powers;
  621.                     nb_pow = LRA_HIGHER_PRC * nb_powers / 100. + 0.5;
  622.                     for (i = HIST_SIZE - 1; i >= 0; i--) {
  623.                         n -= ebur128->i3000.histogram[i].count;
  624.                         if (n < nb_pow) {
  625.                             ebur128->lra_high = ebur128->i3000.histogram[i].loudness;
  626.                             break;
  627.                         }
  628.                     }
  629.  
  630.                     // XXX: show low & high on the graph?
  631.                     ebur128->loudness_range = ebur128->lra_high - ebur128->lra_low;
  632.                 }
  633.             }
  634.  
  635. #define LOG_FMT "M:%6.1f S:%6.1f     I:%6.1f LUFS     LRA:%6.1f LU"
  636.  
  637.             /* push one video frame */
  638.             if (ebur128->do_video) {
  639.                 int x, y, ret;
  640.                 uint8_t *p;
  641.  
  642.                 const int y_loudness_lu_graph = lu_to_y(ebur128, loudness_3000 + 23);
  643.                 const int y_loudness_lu_gauge = lu_to_y(ebur128, loudness_400  + 23);
  644.  
  645.                 /* draw the graph using the short-term loudness */
  646.                 p = pic->data[0] + ebur128->graph.y*pic->linesize[0] + ebur128->graph.x*3;
  647.                 for (y = 0; y < ebur128->graph.h; y++) {
  648.                     const uint8_t *c = get_graph_color(ebur128, y_loudness_lu_graph, y);
  649.  
  650.                     memmove(p, p + 3, (ebur128->graph.w - 1) * 3);
  651.                     memcpy(p + (ebur128->graph.w - 1) * 3, c, 3);
  652.                     p += pic->linesize[0];
  653.                 }
  654.  
  655.                 /* draw the gauge using the momentary loudness */
  656.                 p = pic->data[0] + ebur128->gauge.y*pic->linesize[0] + ebur128->gauge.x*3;
  657.                 for (y = 0; y < ebur128->gauge.h; y++) {
  658.                     const uint8_t *c = get_graph_color(ebur128, y_loudness_lu_gauge, y);
  659.  
  660.                     for (x = 0; x < ebur128->gauge.w; x++)
  661.                         memcpy(p + x*3, c, 3);
  662.                     p += pic->linesize[0];
  663.                 }
  664.  
  665.                 /* draw textual info */
  666.                 drawtext(pic, PAD, PAD - PAD/2, FONT16, font_colors,
  667.                          LOG_FMT "     ", // padding to erase trailing characters
  668.                          loudness_400, loudness_3000,
  669.                          ebur128->integrated_loudness, ebur128->loudness_range);
  670.  
  671.                 /* set pts and push frame */
  672.                 pic->pts = pts;
  673.                 ret = ff_filter_frame(outlink, av_frame_clone(pic));
  674.                 if (ret < 0)
  675.                     return ret;
  676.             }
  677.  
  678.             if (ebur128->metadata) { /* happens only once per filter_frame call */
  679.                 char metabuf[128];
  680. #define SET_META(name, var) do {                                            \
  681.     snprintf(metabuf, sizeof(metabuf), "%.3f", var);                        \
  682.     av_dict_set(&insamples->metadata, "lavfi.r128." name, metabuf, 0);      \
  683. } while (0)
  684.                 SET_META("M",        loudness_400);
  685.                 SET_META("S",        loudness_3000);
  686.                 SET_META("I",        ebur128->integrated_loudness);
  687.                 SET_META("LRA",      ebur128->loudness_range);
  688.                 SET_META("LRA.low",  ebur128->lra_low);
  689.                 SET_META("LRA.high", ebur128->lra_high);
  690.             }
  691.  
  692.             av_log(ctx, ebur128->loglevel, "t: %-10s " LOG_FMT "\n",
  693.                    av_ts2timestr(pts, &outlink->time_base),
  694.                    loudness_400, loudness_3000,
  695.                    ebur128->integrated_loudness, ebur128->loudness_range);
  696.         }
  697.     }
  698.  
  699.     return ff_filter_frame(ctx->outputs[ebur128->do_video], insamples);
  700. }
  701.  
  702. static int query_formats(AVFilterContext *ctx)
  703. {
  704.     EBUR128Context *ebur128 = ctx->priv;
  705.     AVFilterFormats *formats;
  706.     AVFilterChannelLayouts *layouts;
  707.     AVFilterLink *inlink = ctx->inputs[0];
  708.     AVFilterLink *outlink = ctx->outputs[0];
  709.  
  710.     static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_NONE };
  711.     static const int input_srate[] = {48000, -1}; // ITU-R BS.1770 provides coeff only for 48kHz
  712.     static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_RGB24, AV_PIX_FMT_NONE };
  713.  
  714.     /* set optional output video format */
  715.     if (ebur128->do_video) {
  716.         formats = ff_make_format_list(pix_fmts);
  717.         if (!formats)
  718.             return AVERROR(ENOMEM);
  719.         ff_formats_ref(formats, &outlink->in_formats);
  720.         outlink = ctx->outputs[1];
  721.     }
  722.  
  723.     /* set input and output audio formats
  724.      * Note: ff_set_common_* functions are not used because they affect all the
  725.      * links, and thus break the video format negotiation */
  726.     formats = ff_make_format_list(sample_fmts);
  727.     if (!formats)
  728.         return AVERROR(ENOMEM);
  729.     ff_formats_ref(formats, &inlink->out_formats);
  730.     ff_formats_ref(formats, &outlink->in_formats);
  731.  
  732.     layouts = ff_all_channel_layouts();
  733.     if (!layouts)
  734.         return AVERROR(ENOMEM);
  735.     ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);
  736.     ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts);
  737.  
  738.     formats = ff_make_format_list(input_srate);
  739.     if (!formats)
  740.         return AVERROR(ENOMEM);
  741.     ff_formats_ref(formats, &inlink->out_samplerates);
  742.     ff_formats_ref(formats, &outlink->in_samplerates);
  743.  
  744.     return 0;
  745. }
  746.  
  747. static av_cold void uninit(AVFilterContext *ctx)
  748. {
  749.     int i;
  750.     EBUR128Context *ebur128 = ctx->priv;
  751.  
  752.     av_log(ctx, AV_LOG_INFO, "Summary:\n\n"
  753.            "  Integrated loudness:\n"
  754.            "    I:         %5.1f LUFS\n"
  755.            "    Threshold: %5.1f LUFS\n\n"
  756.            "  Loudness range:\n"
  757.            "    LRA:       %5.1f LU\n"
  758.            "    Threshold: %5.1f LUFS\n"
  759.            "    LRA low:   %5.1f LUFS\n"
  760.            "    LRA high:  %5.1f LUFS\n",
  761.            ebur128->integrated_loudness, ebur128->i400.rel_threshold,
  762.            ebur128->loudness_range,      ebur128->i3000.rel_threshold,
  763.            ebur128->lra_low, ebur128->lra_high);
  764.  
  765.     av_freep(&ebur128->y_line_ref);
  766.     av_freep(&ebur128->ch_weighting);
  767.     av_freep(&ebur128->i400.histogram);
  768.     av_freep(&ebur128->i3000.histogram);
  769.     for (i = 0; i < ebur128->nb_channels; i++) {
  770.         av_freep(&ebur128->i400.cache[i]);
  771.         av_freep(&ebur128->i3000.cache[i]);
  772.     }
  773.     for (i = 0; i < ctx->nb_outputs; i++)
  774.         av_freep(&ctx->output_pads[i].name);
  775.     av_frame_free(&ebur128->outpicref);
  776. }
  777.  
  778. static const AVFilterPad ebur128_inputs[] = {
  779.     {
  780.         .name         = "default",
  781.         .type         = AVMEDIA_TYPE_AUDIO,
  782.         .filter_frame = filter_frame,
  783.         .config_props = config_audio_input,
  784.     },
  785.     { NULL }
  786. };
  787.  
  788. AVFilter avfilter_af_ebur128 = {
  789.     .name          = "ebur128",
  790.     .description   = NULL_IF_CONFIG_SMALL("EBU R128 scanner."),
  791.     .priv_size     = sizeof(EBUR128Context),
  792.     .init          = init,
  793.     .uninit        = uninit,
  794.     .query_formats = query_formats,
  795.     .inputs        = ebur128_inputs,
  796.     .outputs       = NULL,
  797.     .priv_class    = &ebur128_class,
  798.     .flags         = AVFILTER_FLAG_DYNAMIC_OUTPUTS,
  799. };
  800.