lavfi/ebur128: add sample and true peak metering.

Metadata injection and logging. Not yet present visually.

Signed-off-by: Jean First <jeanfirst@gmail.com>

doc/filters.texi

@@ -9322,6 +9322,27 @@ verbose logging level
 
 By default, the logging level is set to @var{info}. If the @option{video} or
 the @option{metadata} options are set, it switches to @var{verbose}.
+
+@item peak
+Set peak mode(s).
+
+Available modes can be cumulated (the option is a @code{flag} type). Possible
+values are:
+@table @samp
+@item none
+Disable any peak mode (default).
+@item sample
+Enable sample-peak mode.
+
+Simple peak mode looking for the higher sample value.
+@item true
+Enable true-peak mode.
+
+If enabled, the peak lookup is done on an over-sampled version of the input
+stream for better peak accuracy. This mode requires a build with
+@code{libswresample}.
+@end table
+
 @end table
 
 @subsection Examples

libavfilter/Makefile

@@ -22,6 +22,8 @@ FFLIBS-$(CONFIG_SCALE_FILTER)                += swscale
 FFLIBS-$(CONFIG_SHOWSPECTRUM_FILTER)         += avcodec
 FFLIBS-$(CONFIG_SMARTBLUR_FILTER)            += swscale
 FFLIBS-$(CONFIG_SUBTITLES_FILTER)            += avformat avcodec
+EBUR128LIBS-$(CONFIG_SWRESAMPLE)              = swresample
+FFLIBS-$(CONFIG_EBUR128_FILTER)              += $(EBUR128LIBS-yes)
 
 HEADERS = asrc_abuffer.h                                                \
           avcodec.h                                                     \

libavfilter/f_ebur128.c

@@ -37,6 +37,7 @@
 #include "libavutil/xga_font_data.h"
 #include "libavutil/opt.h"
 #include "libavutil/timestamp.h"
+#include "libswresample/swresample.h"
 #include "audio.h"
 #include "avfilter.h"
 #include "formats.h"
@@ -92,6 +93,16 @@ struct rect { int x, y, w, h; };
 typedef struct {
     const AVClass *class;           ///< AVClass context for log and options purpose
 
+    /* peak metering */
+    int peak_mode;                  ///< enabled peak modes
+    double *true_peaks;             ///< true peaks per channel
+    double *sample_peaks;           ///< sample peaks per channel
+#if CONFIG_SWRESAMPLE
+    SwrContext *swr_ctx;            ///< over-sampling context for true peak metering
+    double *swr_buf;                ///< resampled audio data for true peak metering
+    int swr_linesize;
+#endif
+
     /* video  */
     int do_video;                   ///< 1 if video output enabled, 0 otherwise
     int w, h;                       ///< size of the video output
@@ -130,6 +141,12 @@ typedef struct {
     int metadata;                   ///< whether or not to inject loudness results in frames
 } EBUR128Context;
 
+enum {
+    PEAK_MODE_NONE          = 0,
+    PEAK_MODE_SAMPLES_PEAKS = 1<<1,
+    PEAK_MODE_TRUE_PEAKS    = 1<<2,
+};
+
 #define OFFSET(x) offsetof(EBUR128Context, x)
 #define A AV_OPT_FLAG_AUDIO_PARAM
 #define V AV_OPT_FLAG_VIDEO_PARAM
@@ -142,7 +159,11 @@ static const AVOption ebur128_options[] = {
         { "info",    "information logging level", 0, AV_OPT_TYPE_CONST, {.i64 = AV_LOG_INFO},    INT_MIN, INT_MAX, A|V|F, "level" },
         { "verbose", "verbose logging level",     0, AV_OPT_TYPE_CONST, {.i64 = AV_LOG_VERBOSE}, INT_MIN, INT_MAX, A|V|F, "level" },
     { "metadata", "inject metadata in the filtergraph", OFFSET(metadata), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, A|V|F },
-    { NULL }
+    { "peak", "set peak mode", OFFSET(peak_mode), AV_OPT_TYPE_FLAGS, {.i64 = PEAK_MODE_NONE}, 0, INT_MAX, A|F, "mode" },
+        { "none",   "disable any peak mode",   0, AV_OPT_TYPE_CONST, {.i64 = PEAK_MODE_NONE},          INT_MIN, INT_MAX, A|F, "mode" },
+        { "sample", "enable peak-sample mode", 0, AV_OPT_TYPE_CONST, {.i64 = PEAK_MODE_SAMPLES_PEAKS}, INT_MIN, INT_MAX, A|F, "mode" },
+        { "true",   "enable true-peak mode",   0, AV_OPT_TYPE_CONST, {.i64 = PEAK_MODE_TRUE_PEAKS},    INT_MIN, INT_MAX, A|F, "mode" },
+    { NULL },
 };
 
 AVFILTER_DEFINE_CLASS(ebur128);
@@ -326,9 +347,13 @@ static int config_audio_input(AVFilterLink *inlink)
     AVFilterContext *ctx = inlink->dst;
     EBUR128Context *ebur128 = ctx->priv;
 
-    /* force 100ms framing in case of metadata injection: the frames must have
+    /* Force 100ms framing in case of metadata injection: the frames must have
-     * a granularity of the window overlap to be accurately exploited */
+     * a granularity of the window overlap to be accurately exploited.
-    if (ebur128->metadata)
+     * As for the true peaks mode, it just simplifies the resampling buffer
+     * allocation and the lookup in it (since sample buffers differ in size, it
+     * can be more complex to integrate in the one-sample loop of
+     * filter_frame()). */
+    if (ebur128->metadata || (ebur128->peak_mode & PEAK_MODE_TRUE_PEAKS))
         inlink->min_samples =
         inlink->max_samples =
         inlink->partial_buf_size = inlink->sample_rate / 10;
@@ -383,6 +408,36 @@ static int config_audio_output(AVFilterLink *outlink)
 
     outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
 
+#if CONFIG_SWRESAMPLE
+    if (ebur128->peak_mode & PEAK_MODE_TRUE_PEAKS) {
+        int ret;
+
+        ebur128->swr_buf    = av_malloc(19200 * nb_channels * sizeof(double));
+        ebur128->true_peaks = av_calloc(nb_channels, sizeof(*ebur128->true_peaks));
+        ebur128->swr_ctx    = swr_alloc();
+        if (!ebur128->swr_buf || !ebur128->true_peaks || !ebur128->swr_ctx)
+            return AVERROR(ENOMEM);
+
+        av_opt_set_int(ebur128->swr_ctx, "in_channel_layout",    outlink->channel_layout, 0);
+        av_opt_set_int(ebur128->swr_ctx, "in_sample_rate",       outlink->sample_rate, 0);
+        av_opt_set_sample_fmt(ebur128->swr_ctx, "in_sample_fmt", outlink->format, 0);
+
+        av_opt_set_int(ebur128->swr_ctx, "out_channel_layout",    outlink->channel_layout, 0);
+        av_opt_set_int(ebur128->swr_ctx, "out_sample_rate",       192000, 0);
+        av_opt_set_sample_fmt(ebur128->swr_ctx, "out_sample_fmt", outlink->format, 0);
+
+        ret = swr_init(ebur128->swr_ctx);
+        if (ret < 0)
+            return ret;
+    }
+#endif
+
+    if (ebur128->peak_mode & PEAK_MODE_SAMPLES_PEAKS) {
+        ebur128->sample_peaks = av_calloc(nb_channels, sizeof(*ebur128->sample_peaks));
+        if (!ebur128->sample_peaks)
+            return AVERROR(ENOMEM);
+    }
+
     return 0;
 }
 
@@ -416,6 +471,12 @@ static av_cold int init(AVFilterContext *ctx)
             ebur128->loglevel = AV_LOG_INFO;
     }
 
+    if (!CONFIG_SWRESAMPLE && (ebur128->peak_mode & PEAK_MODE_TRUE_PEAKS)) {
+        av_log(ctx, AV_LOG_ERROR,
+               "True-peak mode requires libswresample to be performed\n");
+        return AVERROR(EINVAL);
+    }
+
     // 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;
@@ -491,6 +552,22 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
     const double *samples = (double *)insamples->data[0];
     AVFrame *pic = ebur128->outpicref;
 
+#if CONFIG_SWRESAMPLE
+    if (ebur128->peak_mode & PEAK_MODE_TRUE_PEAKS) {
+        const double *swr_samples = ebur128->swr_buf;
+        int ret = swr_convert(ebur128->swr_ctx, (uint8_t**)&ebur128->swr_buf, 19200,
+                              (const uint8_t **)insamples->data, nb_samples);
+        if (ret < 0)
+            return ret;
+        for (idx_insample = 0; idx_insample < ret; idx_insample++) {
+            for (ch = 0; ch < nb_channels; ch++) {
+                ebur128->true_peaks[ch] = FFMAX(ebur128->true_peaks[ch], FFABS(*swr_samples));
+                swr_samples++;
+            }
+        }
+    }
+#endif
+
     for (idx_insample = 0; idx_insample < nb_samples; idx_insample++) {
         const int bin_id_400  = ebur128->i400.cache_pos;
         const int bin_id_3000 = ebur128->i3000.cache_pos;
@@ -509,6 +586,9 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
         for (ch = 0; ch < nb_channels; ch++) {
             double bin;
 
+            if (ebur128->peak_mode & PEAK_MODE_SAMPLES_PEAKS)
+                ebur128->sample_peaks[ch] = FFMAX(ebur128->sample_peaks[ch], FFABS(*samples));
+
             ebur128->x[ch * 3] = *samples++; // set X[i]
 
             if (!ebur128->ch_weighting[ch])
@@ -677,22 +757,52 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
 
             if (ebur128->metadata) { /* happens only once per filter_frame call */
                 char metabuf[128];
+#define META_PREFIX "lavfi.r128."
+
 #define SET_META(name, var) do {                                            \
     snprintf(metabuf, sizeof(metabuf), "%.3f", var);                        \
-    av_dict_set(&insamples->metadata, "lavfi.r128." name, metabuf, 0);      \
+    av_dict_set(&insamples->metadata, name, metabuf, 0);                    \
 } while (0)
-                SET_META("M",        loudness_400);
+
-                SET_META("S",        loudness_3000);
+#define SET_META_PEAK(name, ptype) do {                                     \
-                SET_META("I",        ebur128->integrated_loudness);
+    if (ebur128->peak_mode & PEAK_MODE_ ## ptype ## _PEAKS) {               \
-                SET_META("LRA",      ebur128->loudness_range);
+        char key[64];                                                       \
-                SET_META("LRA.low",  ebur128->lra_low);
+        for (ch = 0; ch < nb_channels; ch++) {                              \
-                SET_META("LRA.high", ebur128->lra_high);
+            snprintf(key, sizeof(key),                                      \
+                     META_PREFIX AV_STRINGIFY(name) "_peaks_ch%d", ch);     \
+            SET_META(key, ebur128->name##_peaks[ch]);                       \
+        }                                                                   \
+    }                                                                       \
+} while (0)
+
+                SET_META(META_PREFIX "M",        loudness_400);
+                SET_META(META_PREFIX "S",        loudness_3000);
+                SET_META(META_PREFIX "I",        ebur128->integrated_loudness);
+                SET_META(META_PREFIX "LRA",      ebur128->loudness_range);
+                SET_META(META_PREFIX "LRA.low",  ebur128->lra_low);
+                SET_META(META_PREFIX "LRA.high", ebur128->lra_high);
+
+                SET_META_PEAK(sample, SAMPLES);
+                SET_META_PEAK(true,   TRUE);
             }
 
-            av_log(ctx, ebur128->loglevel, "t: %-10s " LOG_FMT "\n",
+            av_log(ctx, ebur128->loglevel, "t: %-10s " LOG_FMT,
                    av_ts2timestr(pts, &outlink->time_base),
                    loudness_400, loudness_3000,
                    ebur128->integrated_loudness, ebur128->loudness_range);
+
+#define PRINT_PEAKS(str, sp, ptype) do {                        \
+    if (ebur128->peak_mode & PEAK_MODE_ ## ptype ## _PEAKS) {   \
+        av_log(ctx, ebur128->loglevel, " [" str ":");           \
+        for (ch = 0; ch < nb_channels; ch++)                    \
+            av_log(ctx, ebur128->loglevel, " %.5f", sp[ch]);    \
+        av_log(ctx, ebur128->loglevel, "]");                    \
+    }                                                           \
+} while (0)
+
+            PRINT_PEAKS("SPK", ebur128->sample_peaks, SAMPLES);
+            PRINT_PEAKS("TPK", ebur128->true_peaks,   TRUE);
+            av_log(ctx, ebur128->loglevel, "\n");
         }
     }
 
@@ -764,6 +874,8 @@ static av_cold void uninit(AVFilterContext *ctx)
 
     av_freep(&ebur128->y_line_ref);
     av_freep(&ebur128->ch_weighting);
+    av_freep(&ebur128->true_peaks);
+    av_freep(&ebur128->sample_peaks);
     av_freep(&ebur128->i400.histogram);
     av_freep(&ebur128->i3000.histogram);
     for (i = 0; i < ebur128->nb_channels; i++) {
@@ -773,6 +885,10 @@ static av_cold void uninit(AVFilterContext *ctx)
     for (i = 0; i < ctx->nb_outputs; i++)
         av_freep(&ctx->output_pads[i].name);
     av_frame_free(&ebur128->outpicref);
+#if CONFIG_SWRESAMPLE
+    av_freep(&ebur128->swr_buf);
+    swr_free(&ebur128->swr_ctx);
+#endif
 }
 
 static const AVFilterPad ebur128_inputs[] = {