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 + +#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<channel_layout & 1ULL<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