avfilter: add tremolo filter

Signed-off-by: Kyle Swanson <k@ylo.ph>
This commit is contained in:
Kyle Swanson 2015-09-21 10:16:43 -05:00 committed by Paul B Mahol
parent d9c72e0d24
commit a9509ad3f0
6 changed files with 196 additions and 1 deletions

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@ -9,6 +9,7 @@ version <next>:
- stereowiden filter - stereowiden filter
- stereotools filter - stereotools filter
- rubberband filter - rubberband filter
- tremolo filter
version 2.8: version 2.8:

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@ -2568,6 +2568,25 @@ slope
Determine how steep is the filter's shelf transition. Determine how steep is the filter's shelf transition.
@end table @end table
@section tremolo
Sinusoidal amplitude modulation.
The filter accepts the following options:
@table @option
@item f
Modulation frequency in Hertz. Modulation frequencies in the subharmonic range
(20 Hz or lower) will result in a tremolo effect.
This filter may also be used as a ring modulator by specifying
a modulation frequency higher than 20 Hz.
Range is 0.1 - 20000.0. Default value is 5.0 Hz.
@item d
Depth of modulation as a percentage. Range is 0.0 - 1.0.
Default value is 0.5.
@end table
@section volume @section volume
Adjust the input audio volume. Adjust the input audio volume.

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@ -84,6 +84,7 @@ OBJS-$(CONFIG_SILENCEREMOVE_FILTER) += af_silenceremove.o
OBJS-$(CONFIG_STEREOTOOLS_FILTER) += af_stereotools.o OBJS-$(CONFIG_STEREOTOOLS_FILTER) += af_stereotools.o
OBJS-$(CONFIG_STEREOWIDEN_FILTER) += af_stereowiden.o OBJS-$(CONFIG_STEREOWIDEN_FILTER) += af_stereowiden.o
OBJS-$(CONFIG_TREBLE_FILTER) += af_biquads.o OBJS-$(CONFIG_TREBLE_FILTER) += af_biquads.o
OBJS-$(CONFIG_TREMOLO_FILTER) += af_tremolo.o generate_wave_table.o
OBJS-$(CONFIG_VOLUME_FILTER) += af_volume.o OBJS-$(CONFIG_VOLUME_FILTER) += af_volume.o
OBJS-$(CONFIG_VOLUMEDETECT_FILTER) += af_volumedetect.o OBJS-$(CONFIG_VOLUMEDETECT_FILTER) += af_volumedetect.o

173
libavfilter/af_tremolo.c Normal file
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@ -0,0 +1,173 @@
/*
* Copyright (c) 2015 Kyle Swanson <k@ylo.ph>.
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser 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
*/
#include "libavutil/opt.h"
#include "avfilter.h"
#include "internal.h"
#include "audio.h"
#include "generate_wave_table.h"
typedef struct TremoloContext {
const AVClass *class;
double freq;
double depth;
double *wave_table;
int wave_table_index;
int sample_rate;
} TremoloContext;
#define OFFSET(x) offsetof(TremoloContext, x)
#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
static const AVOption tremolo_options[] = {
{ "f", "set frequency in hertz", OFFSET(freq), AV_OPT_TYPE_DOUBLE, {.dbl = 5.0}, 0.1, 20000.0, FLAGS },
{ "d", "set depth as percentage", OFFSET(depth), AV_OPT_TYPE_DOUBLE, {.dbl = 0.5}, 0.0, 1.0, FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(tremolo);
static double trem_env(AVFilterContext *ctx)
{
TremoloContext *s = ctx->priv;
double env = s->wave_table[s->wave_table_index];
s->wave_table_index++;
if (s->wave_table_index >= s->sample_rate / s->freq)
s->wave_table_index = 0;
return 1.0 - (s->depth * env);
}
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
const double *src = (const double *)in->data[0];
const int channels = inlink->channels;
const int nb_samples = in->nb_samples;
AVFrame *out;
double *dst;
int n, c;
if (av_frame_is_writable(in)) {
out = in;
} else {
out = ff_get_audio_buffer(inlink, in->nb_samples);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
av_frame_copy_props(out, in);
}
dst = (double *)out->data[0];
for (n = 0; n < nb_samples; n++) {
const double env = trem_env(ctx);
for (c = 0; c < channels; c++)
dst[c] = src[c] * env;
dst += channels;
src += channels;
}
if (in != out)
av_frame_free(&in);
return ff_filter_frame(outlink, out);
}
static int query_formats(AVFilterContext *ctx)
{
AVFilterFormats *formats;
AVFilterChannelLayouts *layouts;
static const enum AVSampleFormat sample_fmts[] = {
AV_SAMPLE_FMT_DBL,
AV_SAMPLE_FMT_NONE
};
int ret;
layouts = ff_all_channel_counts();
if (!layouts)
return AVERROR(ENOMEM);
ret = ff_set_common_channel_layouts(ctx, layouts);
if (ret < 0)
return ret;
formats = ff_make_format_list(sample_fmts);
if (!formats)
return AVERROR(ENOMEM);
ret = ff_set_common_formats(ctx, formats);
if (ret < 0)
return ret;
formats = ff_all_samplerates();
if (!formats)
return AVERROR(ENOMEM);
return ff_set_common_samplerates(ctx, formats);
}
static av_cold void uninit(AVFilterContext *ctx)
{
TremoloContext *s = ctx->priv;
av_freep(&s->wave_table);
}
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
TremoloContext *s = ctx->priv;
s->sample_rate = inlink->sample_rate;
s->wave_table = av_malloc_array(s->sample_rate / s->freq, sizeof(*s->wave_table));
if (!s->wave_table)
return AVERROR(ENOMEM);
ff_generate_wave_table(WAVE_SIN, AV_SAMPLE_FMT_DBL, s->wave_table, s->sample_rate / s->freq, 0.0, 1.0, 0.0);
s->wave_table_index = 0;
return 0;
}
static const AVFilterPad avfilter_af_tremolo_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.config_props = config_input,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad avfilter_af_tremolo_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
},
{ NULL }
};
AVFilter ff_af_tremolo = {
.name = "tremolo",
.description = NULL_IF_CONFIG_SMALL("Apply tremolo effect."),
.priv_size = sizeof(TremoloContext),
.priv_class = &tremolo_class,
.uninit = uninit,
.query_formats = query_formats,
.inputs = avfilter_af_tremolo_inputs,
.outputs = avfilter_af_tremolo_outputs,
};

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@ -106,6 +106,7 @@ void avfilter_register_all(void)
REGISTER_FILTER(STEREOTOOLS, stereotools, af); REGISTER_FILTER(STEREOTOOLS, stereotools, af);
REGISTER_FILTER(STEREOWIDEN, stereowiden, af); REGISTER_FILTER(STEREOWIDEN, stereowiden, af);
REGISTER_FILTER(TREBLE, treble, af); REGISTER_FILTER(TREBLE, treble, af);
REGISTER_FILTER(TREMOLO, tremolo, af);
REGISTER_FILTER(VOLUME, volume, af); REGISTER_FILTER(VOLUME, volume, af);
REGISTER_FILTER(VOLUMEDETECT, volumedetect, af); REGISTER_FILTER(VOLUMEDETECT, volumedetect, af);

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@ -30,7 +30,7 @@
#include "libavutil/version.h" #include "libavutil/version.h"
#define LIBAVFILTER_VERSION_MAJOR 6 #define LIBAVFILTER_VERSION_MAJOR 6
#define LIBAVFILTER_VERSION_MINOR 6 #define LIBAVFILTER_VERSION_MINOR 7
#define LIBAVFILTER_VERSION_MICRO 100 #define LIBAVFILTER_VERSION_MICRO 100
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \ #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \