Signed-off-by: Paul B Mahol <one...@gmail.com>
---
doc/filters.texi | 61 +++++++++++++++++
libavfilter/Makefile | 1 +
libavfilter/af_agate.c | 170 ++++++++++++++++++++++++++++++++++++++++++++++-
libavfilter/allfilters.c | 1 +
4 files changed, 230 insertions(+), 3 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 0395c7a..ed4a376 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -2531,6 +2531,67 @@ ffmpeg -i main.flac -i sidechain.flac -filter_complex
"[1:a]asplit=2[sc][mix];[0
@end example
@end itemize
+@section sidechaingate
+
+A sidechain gate acts like a normal (wideband) gate but has the ability to
+filter the detected signal before sending it to the gain reduction stage.
+Normally a gate uses the full range signal to detect a level above the
+threshold.
+For example: If you cut all lower frequencies from your sidechain signal
+the gate will decrease the volume of your track only if not enough highs
+appear. With this technique you are able to reduce the resonation of a
+natural drum or remove "rumbling" of muted strokes from a heavily distorted
+guitar.
+It needs two input streams and returns one output stream.
+First input stream will be processed depending on second stream signal.
+
+The filter accepts the following options:
+
+@table @option
+@item level_in
+Set input level before filtering.
+Default is 1. Allowed range is from 0.015625 to 64.
+
+@item range
+Set the level of gain reduction when the signal is below the threshold.
+Default is 0.06125. Allowed range is from 0 to 1.
+
+@item threshold
+If a signal rises above this level the gain reduction is released.
+Default is 0.125. Allowed range is from 0 to 1.
+
+@item ratio
+Set a ratio about which the signal is reduced.
+Default is 2. Allowed range is from 1 to 9000.
+
+@item attack
+Amount of milliseconds the signal has to rise above the threshold before gain
+reduction stops.
+Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
+
+@item release
+Amount of milliseconds the signal has to fall below the threshold before the
+reduction is increased again. Default is 250 milliseconds.
+Allowed range is from 0.01 to 9000.
+
+@item makeup
+Set amount of amplification of signal after processing.
+Default is 1. Allowed range is from 1 to 64.
+
+@item knee
+Curve the sharp knee around the threshold to enter gain reduction more softly.
+Default is 2.828427125. Allowed range is from 1 to 8.
+
+@item detection
+Choose if exact signal should be taken for detection or an RMS like one.
+Default is peak. Can be peak or rms.
+
+@item link
+Choose if the average level between all channels or the louder channel affects
+the reduction.
+Default is average. Can be average or maximum.
+@end table
+
@section silencedetect
Detect silence in an audio stream.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index e31bdaa..582fd0e 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -82,6 +82,7 @@ OBJS-$(CONFIG_REPLAYGAIN_FILTER) +=
af_replaygain.o
OBJS-$(CONFIG_RESAMPLE_FILTER) += af_resample.o
OBJS-$(CONFIG_RUBBERBAND_FILTER) += af_rubberband.o
OBJS-$(CONFIG_SIDECHAINCOMPRESS_FILTER) += af_sidechaincompress.o
+OBJS-$(CONFIG_SIDECHAINGATE_FILTER) += af_agate.o
OBJS-$(CONFIG_SILENCEDETECT_FILTER) += af_silencedetect.o
OBJS-$(CONFIG_SILENCEREMOVE_FILTER) += af_silenceremove.o
OBJS-$(CONFIG_STEREOTOOLS_FILTER) += af_stereotools.o
diff --git a/libavfilter/af_agate.c b/libavfilter/af_agate.c
index d3f74fb..23e45c6 100644
--- a/libavfilter/af_agate.c
+++ b/libavfilter/af_agate.c
@@ -18,6 +18,12 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
+/**
+ * @file
+ * Audio (Sidechain) Gate filter
+ */
+
+#include "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
#include "libavutil/opt.h"
#include "avfilter.h"
@@ -46,12 +52,14 @@ typedef struct AudioGateContext {
double lin_slope;
double attack_coeff;
double release_coeff;
+
+ AVFrame *input_frame[2];
} AudioGateContext;
#define OFFSET(x) offsetof(AudioGateContext, x)
#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
-static const AVOption agate_options[] = {
+static const AVOption options[] = {
{ "level_in", "set input level", OFFSET(level_in),
AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0.015625, 64, A },
{ "range", "set max gain reduction", OFFSET(range),
AV_OPT_TYPE_DOUBLE, {.dbl=0.06125}, 0, 1, A },
{ "threshold", "set threshold", OFFSET(threshold),
AV_OPT_TYPE_DOUBLE, {.dbl=0.125}, 0, 1, A },
@@ -69,6 +77,7 @@ static const AVOption agate_options[] = {
{ NULL }
};
+#define agate_options options
AVFILTER_DEFINE_CLASS(agate);
static int query_formats(AVFilterContext *ctx)
@@ -97,7 +106,7 @@ static int query_formats(AVFilterContext *ctx)
return ff_set_common_samplerates(ctx, formats);
}
-static int config_input(AVFilterLink *inlink)
+static int agate_config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
AudioGateContext *s = ctx->priv;
@@ -221,7 +230,7 @@ static const AVFilterPad inputs[] = {
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.filter_frame = filter_frame,
- .config_props = config_input,
+ .config_props = agate_config_input,
},
{ NULL }
};
@@ -243,3 +252,158 @@ AVFilter ff_af_agate = {
.inputs = inputs,
.outputs = outputs,
};
+
+#if CONFIG_SIDECHAINGATE_FILTER
+
+#define sidechaingate_options options
+AVFILTER_DEFINE_CLASS(sidechaingate);
+
+static int scfilter_frame(AVFilterLink *link, AVFrame *in)
+{
+ AVFilterContext *ctx = link->dst;
+ AudioGateContext *s = ctx->priv;
+ AVFilterLink *outlink = ctx->outputs[0];
+ const double *scsrc;
+ double *sample;
+ int nb_samples;
+ int ret, i;
+
+ for (i = 0; i < 2; i++)
+ if (link == ctx->inputs[i])
+ break;
+ av_assert0(i < 2 && !s->input_frame[i]);
+ s->input_frame[i] = in;
+
+ if (!s->input_frame[0] || !s->input_frame[1])
+ return 0;
+
+ nb_samples = FFMIN(s->input_frame[0]->nb_samples,
+ s->input_frame[1]->nb_samples);
+
+ sample = (double *)s->input_frame[0]->data[0];
+ scsrc = (const double *)s->input_frame[1]->data[0];
+
+ gate(s, sample, sample, scsrc, nb_samples,
+ ctx->inputs[0], ctx->inputs[1]);
+ ret = ff_filter_frame(outlink, s->input_frame[0]);
+
+ s->input_frame[0] = NULL;
+ av_frame_free(&s->input_frame[1]);
+
+ return ret;
+}
+
+static int screquest_frame(AVFilterLink *outlink)
+{
+ AVFilterContext *ctx = outlink->src;
+ AudioGateContext *s = ctx->priv;
+ int i, ret;
+
+ /* get a frame on each input */
+ for (i = 0; i < 2; i++) {
+ AVFilterLink *inlink = ctx->inputs[i];
+ if (!s->input_frame[i] &&
+ (ret = ff_request_frame(inlink)) < 0)
+ return ret;
+
+ /* request the same number of samples on all inputs */
+ if (i == 0)
+ ctx->inputs[1]->request_samples = s->input_frame[0]->nb_samples;
+ }
+
+ return 0;
+}
+
+static int scquery_formats(AVFilterContext *ctx)
+{
+ AVFilterFormats *formats;
+ AVFilterChannelLayouts *layouts = NULL;
+ static const enum AVSampleFormat sample_fmts[] = {
+ AV_SAMPLE_FMT_DBL,
+ AV_SAMPLE_FMT_NONE
+ };
+ int ret, i;
+
+ if (!ctx->inputs[0]->in_channel_layouts ||
+ !ctx->inputs[0]->in_channel_layouts->nb_channel_layouts) {
+ av_log(ctx, AV_LOG_WARNING,
+ "No channel layout for input 1\n");
+ return AVERROR(EAGAIN);
+ }
+
+ if ((ret = ff_add_channel_layout(&layouts,
ctx->inputs[0]->in_channel_layouts->channel_layouts[0])) < 0 ||
+ (ret = ff_channel_layouts_ref(layouts,
&ctx->outputs[0]->in_channel_layouts)) < 0)
+ return ret;
+
+ for (i = 0; i < 2; i++) {
+ layouts = ff_all_channel_counts();
+ if ((ret = ff_channel_layouts_ref(layouts,
&ctx->inputs[i]->out_channel_layouts)) < 0)
+ return ret;
+ }
+
+ formats = ff_make_format_list(sample_fmts);
+ if ((ret = ff_set_common_formats(ctx, formats)) < 0)
+ return ret;
+
+ formats = ff_all_samplerates();
+ return ff_set_common_samplerates(ctx, formats);
+}
+
+static int scconfig_output(AVFilterLink *outlink)
+{
+ AVFilterContext *ctx = outlink->src;
+
+ if (ctx->inputs[0]->sample_rate != ctx->inputs[1]->sample_rate) {
+ av_log(ctx, AV_LOG_ERROR,
+ "Inputs must have the same sample rate "
+ "%d for in0 vs %d for in1\n",
+ ctx->inputs[0]->sample_rate, ctx->inputs[1]->sample_rate);
+ return AVERROR(EINVAL);
+ }
+
+ outlink->sample_rate = ctx->inputs[0]->sample_rate;
+ outlink->time_base = ctx->inputs[0]->time_base;
+ outlink->channel_layout = ctx->inputs[0]->channel_layout;
+ outlink->channels = ctx->inputs[0]->channels;
+
+ agate_config_input(ctx->inputs[0]);
+
+ return 0;
+}
+
+static const AVFilterPad sidechaingate_inputs[] = {
+ {
+ .name = "main",
+ .type = AVMEDIA_TYPE_AUDIO,
+ .filter_frame = scfilter_frame,
+ .needs_writable = 1,
+ .needs_fifo = 1,
+ },{
+ .name = "sidechain",
+ .type = AVMEDIA_TYPE_AUDIO,
+ .filter_frame = scfilter_frame,
+ .needs_fifo = 1,
+ },
+ { NULL }
+};
+
+static const AVFilterPad sidechaingate_outputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_AUDIO,
+ .config_props = scconfig_output,
+ .request_frame = screquest_frame,
+ },
+ { NULL }
+};
+
+AVFilter ff_af_sidechaingate = {
+ .name = "sidechaingate",
+ .description = NULL_IF_CONFIG_SMALL("Audio sidechain gate."),
+ .priv_size = sizeof(AudioGateContext),
+ .priv_class = &sidechaingate_class,
+ .query_formats = scquery_formats,
+ .inputs = sidechaingate_inputs,
+ .outputs = sidechaingate_outputs,
+};
+#endif /* CONFIG_SIDECHAINGATE_FILTER */
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index ccd3f35..9c3778d 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -104,6 +104,7 @@ void avfilter_register_all(void)
REGISTER_FILTER(RESAMPLE, resample, af);
REGISTER_FILTER(RUBBERBAND, rubberband, af);
REGISTER_FILTER(SIDECHAINCOMPRESS, sidechaincompress, af);
+ REGISTER_FILTER(SIDECHAINGATE, sidechaingate, af);
REGISTER_FILTER(SILENCEDETECT, silencedetect, af);
REGISTER_FILTER(SILENCEREMOVE, silenceremove, af);
REGISTER_FILTER(STEREOTOOLS, stereotools, af);
--
1.9.1
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