lavfi: EBU R.128 scanner.

7 files changed, 799 insertions, 1 deletions

diff --git a/Changelog b/Changelog
index bb62a1b379..d65674f5ea 100644
--- a/Changelog
+++ b/Changelog
@@ -3,6 +3,7 @@ releases are sorted from youngest to oldest.
 
 version next:
 - stream disposition information printing in ffprobe
+- filter for loudness analysis following EBU R128
 
 
 version 1.0:
diff --git a/configure b/configure
index b7a8b77f56..829b3ed653 100755
--- a/configure
+++ b/configure
@@ -1901,6 +1901,7 @@ decimate_filter_deps="gpl avcodec"
 delogo_filter_deps="gpl"
 deshake_filter_deps="avcodec"
 drawtext_filter_deps="libfreetype"
+ebur128_filter_deps="gpl"
 flite_filter_deps="libflite"
 frei0r_filter_deps="frei0r dlopen"
 frei0r_filter_extralibs='$ldl'
diff --git a/doc/filters.texi b/doc/filters.texi
index 916aa6f8b9..d9e73b38cc 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -4480,6 +4480,53 @@ setpts=PTS+10/TB
 @end example
 @end itemize
 
+@section ebur128
+
+EBU R128 scanner filter. This filter takes an audio stream as input and outputs
+it unchanged. By default, it logs a message at a frequency of 10Hz with the
+Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
+Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
+
+The filter also has a video output (see the @var{video} option) with a real
+time graph to observe the loudness evolution. The graphic contains the logged
+message mentioned above, so it is not printed anymore when this option is set,
+unless the verbose logging is set. The main graphing area contains the
+short-term loudness (3 seconds of analysis), and the gauge on the right is for
+the momentary loudness (400 milliseconds).
+
+More information about the Loudness Recommendation EBU R128 on
+@url{http://tech.ebu.ch/loudness}.
+
+The filter accepts the following named parameters:
+
+@table @option
+
+@item video
+Activate the video output. The audio stream is passed unchanged whether this
+option is set or no. The video stream will be the first output stream if
+activated. Default is @code{0}.
+
+@item size
+Set the video size. This option is for video only. Default and minimum
+resolution is @code{640x480}.
+
+@item meter
+Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
+@code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
+other integer value between this range is allowed.
+
+@end table
+
+Example of real-time graph using @command{ffplay}, with a EBU scale meter +18:
+@example
+ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
+@end example
+
+Run an analysis with @command{ffmpeg}:
+@example
+ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
+@end example
+
 @section settb, asettb
 
 Set the timebase to use for the output frames timestamps.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index ed1b9b5ff1..3618f10274 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -66,6 +66,7 @@ OBJS-$(CONFIG_ATEMPO_FILTER)                 += af_atempo.o
 OBJS-$(CONFIG_CHANNELMAP_FILTER)             += af_channelmap.o
 OBJS-$(CONFIG_CHANNELSPLIT_FILTER)           += af_channelsplit.o
 OBJS-$(CONFIG_EARWAX_FILTER)                 += af_earwax.o
+OBJS-$(CONFIG_EBUR128_FILTER)                += f_ebur128.o
 OBJS-$(CONFIG_JOIN_FILTER)                   += af_join.o
 OBJS-$(CONFIG_PAN_FILTER)                    += af_pan.o
 OBJS-$(CONFIG_RESAMPLE_FILTER)               += af_resample.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 49f166da7e..348f369520 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -58,6 +58,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (CHANNELMAP,  channelmap,  af);
     REGISTER_FILTER (CHANNELSPLIT,channelsplit,af);
     REGISTER_FILTER (EARWAX,      earwax,      af);
+    REGISTER_FILTER (EBUR128,     ebur128,     af);
     REGISTER_FILTER (JOIN,        join,        af);
     REGISTER_FILTER (PAN,         pan,         af);
     REGISTER_FILTER (SILENCEDETECT, silencedetect, af);
diff --git a/libavfilter/f_ebur128.c b/libavfilter/f_ebur128.c
new file mode 100644
index 0000000000..ff403c8b05
--- /dev/null
+++ b/libavfilter/f_ebur128.c
@@ -0,0 +1,747 @@
+/*
+ * Copyright (c) 2012 Clément Bœsch
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/**
+ * @file
+ * EBU R.128 implementation
+ * @see http://tech.ebu.ch/loudness
+ * @see https://www.youtube.com/watch?v=iuEtQqC-Sqo "EBU R128 Introduction - Florian Camerer"
+ * @todo True Peak
+ * @todo implement start/stop/reset through filter command injection
+ * @todo support other frequencies to avoid resampling
+ */
+
+#include <math.h>
+
+#include "libavutil/audioconvert.h"
+#include "libavutil/avassert.h"
+#include "libavutil/avstring.h"
+#include "libavutil/xga_font_data.h"
+#include "libavutil/opt.h"
+#include "libavutil/timestamp.h"
+#include "audio.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+
+#define MAX_CHANNELS 63
+
+/* pre-filter coefficients */
+#define PRE_B0  1.53512485958697
+#define PRE_B1 -2.69169618940638
+#define PRE_B2  1.19839281085285
+#define PRE_A1 -1.69065929318241
+#define PRE_A2  0.73248077421585
+
+/* RLB-filter coefficients */
+#define RLB_B0  1.0
+#define RLB_B1 -2.0
+#define RLB_B2  1.0
+#define RLB_A1 -1.99004745483398
+#define RLB_A2  0.99007225036621
+
+#define ABS_THRES    -70            ///< silence gate: we discard anything below this absolute (LUFS) threshold
+#define ABS_UP_THRES  10            ///< upper loud limit to consider (ABS_THRES being the minimum)
+#define HIST_GRAIN   100            ///< defines histogram precision
+#define HIST_SIZE  ((ABS_UP_THRES - ABS_THRES) * HIST_GRAIN + 1)
+
+/**
+ * An histogram is an array of HIST_SIZE hist_entry storing all the energies
+ * recorded (with an accuracy of 1/HIST_GRAIN) of the loudnesses from ABS_THRES
+ * (at 0) to ABS_UP_THRES (at HIST_SIZE-1).
+ * This fixed-size system avoids the need of a list of energies growing
+ * infinitely over the time and is thus more scalable.
+ */
+struct hist_entry {
+    int count;                      ///< how many times the corresponding value occurred
+    double energy;                  ///< E = 10^((L + 0.691) / 10)
+    double loudness;                ///< L = -0.691 + 10 * log10(E)
+};
+
+struct integrator {
+    double *cache[MAX_CHANNELS];    ///< window of filtered samples (N ms)
+    int cache_pos;                  ///< focus on the last added bin in the cache array
+    double sum[MAX_CHANNELS];       ///< sum of the last N ms filtered samples (cache content)
+    int filled;                     ///< 1 if the cache is completely filled, 0 otherwise
+    double rel_threshold;           ///< relative threshold
+    double sum_kept_powers;         ///< sum of the powers (weighted sums) above absolute threshold
+    int nb_kept_powers;             ///< number of sum above absolute threshold
+    struct hist_entry *histogram;   ///< histogram of the powers, used to compute LRA and I
+};
+
+struct rect { int x, y, w, h; };
+
+typedef struct {
+    const AVClass *class;           ///< AVClass context for log and options purpose
+
+    /* video  */
+    int do_video;                   ///< 1 if video output enabled, 0 otherwise
+    int w, h;                       ///< size of the video output
+    struct rect text;               ///< rectangle for the LU legend on the left
+    struct rect graph;              ///< rectangle for the main graph in the center
+    struct rect gauge;              ///< rectangle for the gauge on the right
+    AVFilterBufferRef *outpicref;   ///< output picture reference, updated regularly
+    int meter;                      ///< select a EBU mode between +9 and +18
+    int scale_range;                ///< the range of LU values according to the meter
+    int y_zero_lu;                  ///< the y value (pixel position) for 0 LU
+    int *y_line_ref;                ///< y reference values for drawing the LU lines in the graph and the gauge
+
+    /* audio */
+    int nb_channels;                ///< number of channels in the input
+    double *ch_weighting;           ///< channel weighting mapping
+    int sample_count;               ///< sample count used for refresh frequency, reset at refresh
+
+    /* Filter caches.
+     * The mult by 3 in the following is for X[i], X[i-1] and X[i-2] */
+    double x[MAX_CHANNELS * 3];     ///< 3 input samples cache for each channel
+    double y[MAX_CHANNELS * 3];     ///< 3 pre-filter samples cache for each channel
+    double z[MAX_CHANNELS * 3];     ///< 3 RLB-filter samples cache for each channel
+
+#define I400_BINS  (48000 * 4 / 10)
+#define I3000_BINS (48000 * 3)
+    struct integrator i400;         ///< 400ms integrator, used for Momentary loudness  (M), and Integrated loudness (I)
+    struct integrator i3000;        ///<    3s integrator, used for Short term loudness (S), and Loudness Range      (LRA)
+
+    /* I and LRA specific */
+    double integrated_loudness;     ///< integrated loudness in LUFS (I)
+    double loudness_range;          ///< loudness range in LU (LRA)
+    double lra_low, lra_high;       ///< low and high LRA values
+} EBUR128Context;
+
+#define OFFSET(x) offsetof(EBUR128Context, x)
+#define A AV_OPT_FLAG_AUDIO_PARAM
+#define V AV_OPT_FLAG_VIDEO_PARAM
+#define F AV_OPT_FLAG_FILTERING_PARAM
+static const AVOption ebur128_options[] = {
+    { "video", "set video output", OFFSET(do_video), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, V|F },
+    { "size",  "set video size",   OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "640x480"}, 0, 0, V|F },
+    { "meter", "set scale meter (+9 to +18)",  OFFSET(meter), AV_OPT_TYPE_INT, {.i64 = 9}, 9, 18, V|F },
+    { NULL },
+};
+
+AVFILTER_DEFINE_CLASS(ebur128);
+
+static const uint8_t graph_colors[] = {
+    0xdd, 0x66, 0x66,   // value above 0LU non reached
+    0x66, 0x66, 0xdd,   // value below 0LU non reached
+    0x96, 0x33, 0x33,   // value above 0LU reached
+    0x33, 0x33, 0x96,   // value below 0LU reached
+    0xdd, 0x96, 0x96,   // value above 0LU line non reached
+    0x96, 0x96, 0xdd,   // value below 0LU line non reached
+    0xdd, 0x33, 0x33,   // value above 0LU line reached
+    0x33, 0x33, 0xdd,   // value below 0LU line reached
+};
+
+static const uint8_t *get_graph_color(const EBUR128Context *ebur128, int v, int y)
+{
+    const int below0  = y > ebur128->y_zero_lu;
+    const int reached = y >= v;
+    const int line    = ebur128->y_line_ref[y] || y == ebur128->y_zero_lu;
+    const int colorid = 4*line + 2*reached + below0;
+    return graph_colors + 3*colorid;
+}
+
+static inline int lu_to_y(const EBUR128Context *ebur128, double v)
+{
+    v += 2 * ebur128->meter;                            // make it in range [0;...]
+    v  = av_clipf(v, 0, ebur128->scale_range);          // make sure it's in the graph scale
+    v  = ebur128->scale_range - v;                      // invert value (y=0 is on top)
+    return v * ebur128->graph.h / ebur128->scale_range; // rescale from scale range to px height
+}
+
+#define FONT8   0
+#define FONT16  1
+
+static const uint8_t font_colors[] = {
+    0xdd, 0xdd, 0x00,
+    0x00, 0x96, 0x96,
+};
+
+static void drawtext(AVFilterBufferRef *pic, int x, int y, int ftid, const uint8_t *color, const char *fmt, ...)
+{
+    int i;
+    char buf[128] = {0};
+    const uint8_t *font;
+    int font_height;
+    va_list vl;
+
+    if      (ftid == FONT16) font = avpriv_vga16_font, font_height = 16;
+    else if (ftid == FONT8)  font = avpriv_cga_font,   font_height =  8;
+    else return;
+
+    va_start(vl, fmt);
+    vsnprintf(buf, sizeof(buf), fmt, vl);
+    va_end(vl);
+
+    for (i = 0; buf[i]; i++) {
+        int char_y, mask;
+        uint8_t *p = pic->data[0] + y*pic->linesize[0] + (x + i*8)*3;
+
+        for (char_y = 0; char_y < font_height; char_y++) {
+            for (mask = 0x80; mask; mask >>= 1) {
+                if (font[buf[i] * font_height + char_y] & mask)
+                    memcpy(p, color, 3);
+                else
+                    memcpy(p, "\x00\x00\x00", 3);
+                p += 3;
+            }
+            p += pic->linesize[0] - 8*3;
+        }
+    }
+}
+
+static void drawline(AVFilterBufferRef *pic, int x, int y, int len, int step)
+{
+    int i;
+    uint8_t *p = pic->data[0] + y*pic->linesize[0] + x*3;
+
+    for (i = 0; i < len; i++) {
+        memcpy(p, "\x00\xff\x00", 3);
+        p += step;
+    }
+}
+
+static int config_video_output(AVFilterLink *outlink)
+{
+    int i, x, y;
+    uint8_t *p;
+    AVFilterContext *ctx = outlink->src;
+    EBUR128Context *ebur128 = ctx->priv;
+    AVFilterBufferRef *outpicref;
+
+    /* check if there is enough space to represent everything decently */
+    if (ebur128->w < 640 || ebur128->h < 480) {
+        av_log(ctx, AV_LOG_ERROR, "Video size %dx%d is too small, "
+               "minimum size is 640x480\n", ebur128->w, ebur128->h);
+        return AVERROR(EINVAL);
+    }
+    outlink->w = ebur128->w;
+    outlink->h = ebur128->h;
+
+#define PAD 8
+
+    /* configure text area position and size */
+    ebur128->text.x  = PAD;
+    ebur128->text.y  = 40;
+    ebur128->text.w  = 3 * 8;   // 3 characters
+    ebur128->text.h  = ebur128->h - PAD - ebur128->text.y;
+
+    /* configure gauge position and size */
+    ebur128->gauge.w = 20;
+    ebur128->gauge.h = ebur128->text.h;
+    ebur128->gauge.x = ebur128->w - PAD - ebur128->gauge.w;
+    ebur128->gauge.y = ebur128->text.y;
+
+    /* configure graph position and size */
+    ebur128->graph.x = ebur128->text.x + ebur128->text.w + PAD;
+    ebur128->graph.y = ebur128->gauge.y;
+    ebur128->graph.w = ebur128->gauge.x - ebur128->graph.x - PAD;
+    ebur128->graph.h = ebur128->gauge.h;
+
+    /* graph and gauge share the LU-to-pixel code */
+    av_assert0(ebur128->graph.h == ebur128->gauge.h);
+
+    /* prepare the initial picref buffer */
+    avfilter_unref_bufferp(&ebur128->outpicref);
+    ebur128->outpicref = outpicref =
+        ff_get_video_buffer(outlink, AV_PERM_WRITE|AV_PERM_PRESERVE|AV_PERM_REUSE2,
+                            outlink->w, outlink->h);
+    if (!outpicref)
+        return AVERROR(ENOMEM);
+    outlink->sample_aspect_ratio = (AVRational){1,1};
+
+    /* init y references values (to draw LU lines) */
+    ebur128->y_line_ref = av_calloc(ebur128->graph.h + 1, sizeof(*ebur128->y_line_ref));
+    if (!ebur128->y_line_ref)
+        return AVERROR(ENOMEM);
+
+    /* black background */
+    memset(outpicref->data[0], 0, ebur128->h * outpicref->linesize[0]);
+
+    /* draw LU legends */
+    drawtext(outpicref, PAD, PAD+16, FONT8, font_colors+3, " LU");
+    for (i = ebur128->meter; i >= -ebur128->meter * 2; i--) {
+        y = lu_to_y(ebur128, i);
+        x = PAD + (i < 10 && i > -10) * 8;
+        ebur128->y_line_ref[y] = i;
+        y -= 4; // -4 to center vertically
+        drawtext(outpicref, x, y + ebur128->graph.y, FONT8, font_colors+3,
+                 "%c%d", i < 0 ? '-' : i > 0 ? '+' : ' ', FFABS(i));
+    }
+
+    /* draw graph */
+    ebur128->y_zero_lu = lu_to_y(ebur128, 0);
+    p = outpicref->data[0] + ebur128->graph.y * outpicref->linesize[0]
+                           + ebur128->graph.x * 3;
+    for (y = 0; y < ebur128->graph.h; y++) {
+        const uint8_t *c = get_graph_color(ebur128, INT_MAX, y);
+
+        for (x = 0; x < ebur128->graph.w; x++)
+            memcpy(p + x*3, c, 3);
+        p += outpicref->linesize[0];
+    }
+
+    /* draw fancy rectangles around the graph and the gauge */
+#define DRAW_RECT(r) do { \
+    drawline(outpicref, r.x,       r.y - 1,   r.w, 3); \
+    drawline(outpicref, r.x,       r.y + r.h, r.w, 3); \
+    drawline(outpicref, r.x - 1,   r.y,       r.h, outpicref->linesize[0]); \
+    drawline(outpicref, r.x + r.w, r.y,       r.h, outpicref->linesize[0]); \
+} while (0)
+    DRAW_RECT(ebur128->graph);
+    DRAW_RECT(ebur128->gauge);
+
+    return 0;
+}
+
+static int config_audio_output(AVFilterLink *outlink)
+{
+    int i;
+    AVFilterContext *ctx = outlink->src;
+    EBUR128Context *ebur128 = ctx->priv;
+    const int nb_channels = av_get_channel_layout_nb_channels(outlink->channel_layout);
+
+#define BACK_MASK (AV_CH_BACK_LEFT    |AV_CH_BACK_CENTER    |AV_CH_BACK_RIGHT| \
+                   AV_CH_TOP_BACK_LEFT|AV_CH_TOP_BACK_CENTER|AV_CH_TOP_BACK_RIGHT)
+
+    ebur128->nb_channels  = nb_channels;
+    ebur128->ch_weighting = av_calloc(nb_channels, sizeof(*ebur128->ch_weighting));
+    if (!ebur128->ch_weighting)
+        return AVERROR(ENOMEM);
+
+    for (i = 0; i < nb_channels; i++) {
+
+        /* channel weighting */
+        if ((outlink->channel_layout & 1ULL<<i) == AV_CH_LOW_FREQUENCY)
+            continue;
+        if (outlink->channel_layout & 1ULL<<i & BACK_MASK)
+            ebur128->ch_weighting[i] = 1.41;
+        else
+            ebur128->ch_weighting[i] = 1.0;
+
+        /* bins buffer for the two integration window (400ms and 3s) */
+        ebur128->i400.cache[i]  = av_calloc(I400_BINS,  sizeof(*ebur128->i400.cache[0]));
+        ebur128->i3000.cache[i] = av_calloc(I3000_BINS, sizeof(*ebur128->i3000.cache[0]));
+        if (!ebur128->i400.cache[i] || !ebur128->i3000.cache[i])
+            return AVERROR(ENOMEM);
+    }
+
+    return 0;
+}
+
+#define ENERGY(loudness) (pow(10, ((loudness) + 0.691) / 10.))
+#define LOUDNESS(energy) (-0.691 + 10 * log10(energy))
+
+static struct hist_entry *get_histogram(void)
+{
+    int i;
+    struct hist_entry *h = av_calloc(HIST_SIZE, sizeof(*h));
+
+    for (i = 0; i < HIST_SIZE; i++) {
+        h[i].loudness = i / (double)HIST_GRAIN + ABS_THRES;
+        h[i].energy   = ENERGY(h[i].loudness);
+    }
+    return h;
+}
+
+static av_cold int init(AVFilterContext *ctx, const char *args)
+{
+    int ret;
+    EBUR128Context *ebur128 = ctx->priv;
+    AVFilterPad pad;
+
+    ebur128->class = &ebur128_class;
+    av_opt_set_defaults(ebur128);
+
+    if ((ret = av_set_options_string(ebur128, args, "=", ":")) < 0)
+        return ret;
+
+    // if meter is  +9 scale, scale range is from -18 LU to  +9 LU (or 3*9)
+    // if meter is +18 scale, scale range is from -36 LU to +18 LU (or 3*18)
+    ebur128->scale_range = 3 * ebur128->meter;
+
+    ebur128->i400.histogram  = get_histogram();
+    ebur128->i3000.histogram = get_histogram();
+
+    ebur128->integrated_loudness = ABS_THRES;
+    ebur128->loudness_range = 0;
+
+    /* insert output pads */
+    if (ebur128->do_video) {
+        pad = (AVFilterPad){
+            .name         = av_strdup("out0"),
+            .type         = AVMEDIA_TYPE_VIDEO,
+            .config_props = config_video_output,
+        };
+        if (!pad.name)
+            return AVERROR(ENOMEM);
+        ff_insert_outpad(ctx, 0, &pad);
+    }
+    pad = (AVFilterPad){
+        .name         = av_asprintf("out%d", ebur128->do_video),
+        .type         = AVMEDIA_TYPE_AUDIO,
+        .config_props = config_audio_output,
+    };
+    if (!pad.name)
+        return AVERROR(ENOMEM);
+    ff_insert_outpad(ctx, ebur128->do_video, &pad);
+
+    /* summary */
+    av_log(ctx, AV_LOG_VERBOSE, "EBU +%d scale\n", ebur128->meter);
+
+    return 0;
+}
+
+#define HIST_POS(power) (int)(((power) - ABS_THRES) * HIST_GRAIN)
+
+/* loudness and power should be set such as loudness = -0.691 +
+ * 10*log10(power), we just avoid doing that calculus two times */
+static int gate_update(struct integrator *integ, double power,
+                       double loudness, int gate_thres)
+{
+    int ipower;
+    double relative_threshold;
+    int gate_hist_pos;
+
+    /* update powers histograms by incrementing current power count */
+    ipower = av_clip(HIST_POS(loudness), 0, HIST_SIZE - 1);
+    integ->histogram[ipower].count++;
+
+    /* compute relative threshold and get its position in the histogram */
+    integ->sum_kept_powers += power;
+    integ->nb_kept_powers++;
+    relative_threshold = integ->sum_kept_powers / integ->nb_kept_powers;
+    if (!relative_threshold)
+        relative_threshold = 1e-12;
+    integ->rel_threshold = LOUDNESS(relative_threshold) + gate_thres;
+    gate_hist_pos = av_clip(HIST_POS(integ->rel_threshold), 0, HIST_SIZE - 1);
+
+    return gate_hist_pos;
+}
+
+static int filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples)
+{
+    int i, ch;
+    AVFilterContext *ctx = inlink->dst;
+    EBUR128Context *ebur128 = ctx->priv;
+    const int nb_channels = ebur128->nb_channels;
+    const int nb_samples  = insamples->audio->nb_samples;
+    const double *samples = (double *)insamples->data[0];
+    AVFilterBufferRef *pic = ebur128->outpicref;
+
+    for (i = 0; i < nb_samples; i++) {
+        const int bin_id_400  = ebur128->i400.cache_pos;
+        const int bin_id_3000 = ebur128->i3000.cache_pos;
+
+#define MOVE_TO_NEXT_CACHED_ENTRY(time) do {                \
+    ebur128->i##time.cache_pos++;                           \
+    if (ebur128->i##time.cache_pos == I##time##_BINS) {     \
+        ebur128->i##time.filled    = 1;                     \
+        ebur128->i##time.cache_pos = 0;                     \
+    }                                                       \
+} while (0)
+
+        MOVE_TO_NEXT_CACHED_ENTRY(400);
+        MOVE_TO_NEXT_CACHED_ENTRY(3000);
+
+        for (ch = 0; ch < nb_channels; ch++) {
+            double bin;
+
+            if (!ebur128->ch_weighting[ch])
+                continue;
+
+            /* Y[i] = X[i]*b0 + X[i-1]*b1 + X[i-2]*b2 - Y[i-1]*a1 - Y[i-2]*a2 */
+#define FILTER(Y, X, name) do {                                                 \
+            double *dst = ebur128->Y + ch*3;                                    \
+            double *src = ebur128->X + ch*3;                                    \
+            dst[2] = dst[1];                                                    \
+            dst[1] = dst[0];                                                    \
+            dst[0] = src[0]*name##_B0 + src[1]*name##_B1 + src[2]*name##_B2     \
+                                      - dst[1]*name##_A1 - dst[2]*name##_A2;    \
+} while (0)
+
+            ebur128->x[ch * 3] = *samples++; // set X[i]
+
+            // TODO: merge both filters in one?
+            FILTER(y, x, PRE);  // apply pre-filter
+            ebur128->x[ch * 3 + 2] = ebur128->x[ch * 3 + 1];
+            ebur128->x[ch * 3 + 1] = ebur128->x[ch * 3    ];
+            FILTER(z, y, RLB);  // apply RLB-filter
+
+            bin = ebur128->z[ch * 3] * ebur128->z[ch * 3];
+
+            /* add the new value, and limit the sum to the cache size (400ms or 3s)
+             * by removing the oldest one */
+            ebur128->i400.sum [ch] = ebur128->i400.sum [ch] + bin - ebur128->i400.cache [ch][bin_id_400];
+            ebur128->i3000.sum[ch] = ebur128->i3000.sum[ch] + bin - ebur128->i3000.cache[ch][bin_id_3000];
+
+            /* override old cache entry with the new value */
+            ebur128->i400.cache [ch][bin_id_400 ] = bin;
+            ebur128->i3000.cache[ch][bin_id_3000] = bin;
+        }
+
+        /* For integrated loudness, gating blocks are 400ms long with 75%
+         * overlap (see BS.1770-2 p5), so a re-computation is needed each 100ms
+         * (4800 samples at 48kHz). */
+        if (++ebur128->sample_count == 4800) {
+            double loudness_400, loudness_3000;
+            double power_400 = 1e-12, power_3000 = 1e-12;
+            AVFilterLink *outlink = ctx->outputs[0];
+            const int64_t pts = insamples->pts +
+                av_rescale_q(i, (AVRational){ 1, inlink->sample_rate },
+                             outlink->time_base);
+
+            ebur128->sample_count = 0;
+
+#define COMPUTE_LOUDNESS(m, time) do {                                              \
+    if (ebur128->i##time.filled) {                                                  \
+        /* weighting sum of the last <time> ms */                                   \
+        for (ch = 0; ch < nb_channels; ch++)                                        \
+            power_##time += ebur128->ch_weighting[ch] * ebur128->i##time.sum[ch];   \
+        power_##time /= I##time##_BINS;                                             \
+    }                                                                               \
+    loudness_##time = LOUDNESS(power_##time);                                       \
+} while (0)
+
+            COMPUTE_LOUDNESS(M,  400);
+            COMPUTE_LOUDNESS(S, 3000);
+
+            /* Integrated loudness */
+#define I_GATE_THRES -10  // initially defined to -8 LU in the first EBU standard
+
+            if (loudness_400 >= ABS_THRES) {
+                double integrated_sum = 0;
+                int nb_integrated = 0;
+                int gate_hist_pos = gate_update(&ebur128->i400, power_400,
+                                                loudness_400, I_GATE_THRES);
+
+                /* compute integrated loudness by summing the histogram values
+                 * above the relative threshold */
+                for (i = gate_hist_pos; i < HIST_SIZE; i++) {
+                    const int nb_v = ebur128->i400.histogram[i].count;
+                    nb_integrated  += nb_v;
+                    integrated_sum += nb_v * ebur128->i400.histogram[i].energy;
+                }
+                if (nb_integrated)
+                    ebur128->integrated_loudness = LOUDNESS(integrated_sum / nb_integrated);
+            }
+
+            /* LRA */
+#define LRA_GATE_THRES -20
+#define LRA_LOWER_PRC   10
+#define LRA_HIGHER_PRC  95
+
+            /* XXX: example code in EBU 3342 is ">=" but formula in BS.1770
+             * specs is ">" */
+            if (loudness_3000 >= ABS_THRES) {
+                int nb_powers = 0;
+                int gate_hist_pos = gate_update(&ebur128->i3000, power_3000,
+                                                loudness_3000, LRA_GATE_THRES);
+
+                for (i = gate_hist_pos; i < HIST_SIZE; i++)
+                    nb_powers += ebur128->i3000.histogram[i].count;
+                if (nb_powers) {
+                    int n, nb_pow;
+
+                    /* get lower loudness to consider */
+                    n = 0;
+                    nb_pow = LRA_LOWER_PRC  * nb_powers / 100. + 0.5;
+                    for (i = gate_hist_pos; i < HIST_SIZE; i++) {
+                        n += ebur128->i3000.histogram[i].count;
+                        if (n >= nb_pow) {
+                            ebur128->lra_low = ebur128->i3000.histogram[i].loudness;
+                            break;
+                        }
+                    }
+
+                    /* get higher loudness to consider */
+                    n = nb_powers;
+                    nb_pow = LRA_HIGHER_PRC * nb_powers / 100. + 0.5;
+                    for (i = HIST_SIZE - 1; i >= 0; i--) {
+                        n -= ebur128->i3000.histogram[i].count;
+                        if (n < nb_pow) {
+                            ebur128->lra_high = ebur128->i3000.histogram[i].loudness;
+                            break;
+                        }
+                    }
+
+                    // XXX: show low & high on the graph?
+                    ebur128->loudness_range = ebur128->lra_high - ebur128->lra_low;
+                }
+            }
+
+#define LOG_FMT "M:%6.1f S:%6.1f     I:%6.1f LUFS     LRA:%6.1f LU"
+
+            /* push one video frame */
+            if (ebur128->do_video) {
+                int x, y, ret;
+                uint8_t *p;
+
+                const int y_loudness_lu_graph = lu_to_y(ebur128, loudness_3000 + 23);
+                const int y_loudness_lu_gauge = lu_to_y(ebur128, loudness_400  + 23);
+
+                /* draw the graph using the short-term loudness */
+                p = pic->data[0] + ebur128->graph.y*pic->linesize[0] + ebur128->graph.x*3;
+                for (y = 0; y < ebur128->graph.h; y++) {
+                    const uint8_t *c = get_graph_color(ebur128, y_loudness_lu_graph, y);
+
+                    memmove(p, p + 3, (ebur128->graph.w - 1) * 3);
+                    memcpy(p + (ebur128->graph.w - 1) * 3, c, 3);
+                    p += pic->linesize[0];
+                }
+
+                /* draw the gauge using the momentary loudness */
+                p = pic->data[0] + ebur128->gauge.y*pic->linesize[0] + ebur128->gauge.x*3;
+                for (y = 0; y < ebur128->gauge.h; y++) {
+                    const uint8_t *c = get_graph_color(ebur128, y_loudness_lu_gauge, y);
+
+                    for (x = 0; x < ebur128->gauge.w; x++)
+                        memcpy(p + x*3, c, 3);
+                    p += pic->linesize[0];
+                }
+
+                /* draw textual info */
+                drawtext(pic, PAD, PAD - PAD/2, FONT16, font_colors,
+                         LOG_FMT "     ", // padding to erase trailing characters
+                         loudness_400, loudness_3000,
+                         ebur128->integrated_loudness, ebur128->loudness_range);
+
+                /* set pts and push frame */
+                pic->pts = pts;
+                if ((ret = ff_start_frame(outlink, avfilter_ref_buffer(pic, ~AV_PERM_WRITE)) < 0) < 0 ||
+                    (ret = ff_draw_slice(outlink, 0, outlink->h, 1)) < 0 ||
+                    (ret = ff_end_frame(outlink)) < 0)
+                    return ret;
+            }
+
+            av_log(ctx, ebur128->do_video ? AV_LOG_VERBOSE : AV_LOG_INFO,
+                   "t: %-10s " LOG_FMT "\n", av_ts2timestr(pts, &outlink->time_base),
+                   loudness_400, loudness_3000,
+                   ebur128->integrated_loudness, ebur128->loudness_range);
+        }
+    }
+
+    return ff_filter_samples(ctx->outputs[ebur128->do_video], insamples);
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    EBUR128Context *ebur128 = ctx->priv;
+    AVFilterFormats *formats;
+    AVFilterChannelLayouts *layouts;
+    AVFilterLink *inlink = ctx->inputs[0];
+    AVFilterLink *outlink = ctx->outputs[0];
+
+    static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_DBL, -1 };
+    static const int input_srate[] = {48000, -1}; // ITU-R BS.1770 provides coeff only for 48kHz
+    static const enum PixelFormat pix_fmts[] = { PIX_FMT_RGB24, -1 };
+
+    /* set input audio formats */
+    formats = ff_make_format_list(sample_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    ff_formats_ref(formats, &inlink->out_formats);
+
+    layouts = ff_all_channel_layouts();
+    if (!layouts)
+        return AVERROR(ENOMEM);
+    ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);
+
+    formats = ff_make_format_list(input_srate);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    ff_formats_ref(formats, &inlink->out_samplerates);
+
+    /* set optional output video format */
+    if (ebur128->do_video) {
+        formats = ff_make_format_list(pix_fmts);
+        if (!formats)
+            return AVERROR(ENOMEM);
+        ff_formats_ref(formats, &outlink->in_formats);
+        outlink = ctx->outputs[1];
+    }
+
+    /* set audio output formats (same as input since it's just a passthrough) */
+    formats = ff_make_format_list(sample_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    ff_formats_ref(formats, &outlink->in_formats);
+
+    layouts = ff_all_channel_layouts();
+    if (!layouts)
+        return AVERROR(ENOMEM);
+    ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts);
+
+    formats = ff_make_format_list(input_srate);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    ff_formats_ref(formats, &outlink->in_samplerates);
+
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    int i;
+    EBUR128Context *ebur128 = ctx->priv;
+
+    av_log(ctx, AV_LOG_INFO, "Summary:\n\n"
+           "  Integrated loudness:\n"
+           "    I:         %5.1f LUFS\n"
+           "    Threshold: %5.1f LUFS\n\n"
+           "  Loudness range:\n"
+           "    LRA:       %5.1f LU\n"
+           "    Threshold: %5.1f LUFS\n"
+           "    LRA low:   %5.1f LUFS\n"
+           "    LRA high:  %5.1f LUFS\n",
+           ebur128->integrated_loudness, ebur128->i400.rel_threshold,
+           ebur128->loudness_range,      ebur128->i3000.rel_threshold,
+           ebur128->lra_low, ebur128->lra_high);
+
+    av_freep(&ebur128->y_line_ref);
+    av_freep(&ebur128->ch_weighting);
+    av_freep(&ebur128->i400.histogram);
+    av_freep(&ebur128->i3000.histogram);
+    for (i = 0; i < ebur128->nb_channels; i++) {
+        av_freep(&ebur128->i400.cache[i]);
+        av_freep(&ebur128->i3000.cache[i]);
+    }
+    for (i = 0; i < ctx->nb_outputs; i++)
+        av_freep(&ctx->output_pads[i].name);
+    avfilter_unref_bufferp(&ebur128->outpicref);
+}
+
+AVFilter avfilter_af_ebur128 = {
+    .name          = "ebur128",
+    .description   = NULL_IF_CONFIG_SMALL("EBU R128 scanner."),
+    .priv_size     = sizeof(EBUR128Context),
+    .init          = init,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+
+    .inputs = (const AVFilterPad[]) {
+        { .name             = "default",
+          .type             = AVMEDIA_TYPE_AUDIO,
+          .get_audio_buffer = ff_null_get_audio_buffer,
+          .filter_samples   = filter_samples, },
+        { .name = NULL }
+    },
+    .outputs = NULL,
+};
diff --git a/libavfilter/version.h b/libavfilter/version.h
index e4520a3431..2acb3e6368 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -29,7 +29,7 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  3
-#define LIBAVFILTER_VERSION_MINOR  18
+#define LIBAVFILTER_VERSION_MINOR  19
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \