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/*
* 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/mem.h"
#include "libavutil/opt.h"
#include "avfilter.h"
#include "internal.h"
#include "audio.h"
#include "generate_wave_table.h"
typedef struct VibratoContext {
const AVClass *class;
double freq;
double depth;
int channels;
double **buf;
int buf_index;
int buf_size;
double *wave_table;
int wave_table_index;
int wave_table_size;
} VibratoContext;
#define OFFSET(x) offsetof(VibratoContext, x)
#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
static const AVOption vibrato_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}, 0.00, 1.0, FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(vibrato);
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
VibratoContext *s = ctx->priv;
const int wave_table_size = s->wave_table_size;
const double *wave_table = s->wave_table;
AVFilterLink *outlink = ctx->outputs[0];
const int channels = s->channels;
const int buf_size = s->buf_size;
const double depth = s->depth;
int wave_table_index = s->wave_table_index;
int buf_index = s->buf_index;
AVFrame *out;
const double *src;
double *dst;
if (av_frame_is_writable(in)) {
out = in;
} else {
out = ff_get_audio_buffer(outlink, in->nb_samples);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
av_frame_copy_props(out, in);
}
for (int n = 0; n < in->nb_samples; n++) {
int samp1_index, samp2_index;
double integer, decimal;
decimal = modf(depth * wave_table[wave_table_index], &integer);
wave_table_index++;
if (wave_table_index >= wave_table_size)
wave_table_index -= wave_table_size;
samp1_index = buf_index + integer;
if (samp1_index >= buf_size)
samp1_index -= buf_size;
samp2_index = samp1_index + 1;
if (samp2_index >= buf_size)
samp2_index -= buf_size;
for (int c = 0; c < channels; c++) {
double *buf, this_samp;
src = (const double *)in->extended_data[c];
dst = (double *)out->extended_data[c];
buf = s->buf[c];
this_samp = src[n];
dst[n] = buf[samp1_index] + (decimal * (buf[samp2_index] - buf[samp1_index]));
buf[buf_index] = this_samp;
}
buf_index++;
if (buf_index >= buf_size)
buf_index -= buf_size;
}
s->wave_table_index = wave_table_index;
s->buf_index = buf_index;
if (in != out)
av_frame_free(&in);
return ff_filter_frame(outlink, out);
}
static av_cold void uninit(AVFilterContext *ctx)
{
VibratoContext *s = ctx->priv;
int c;
av_freep(&s->wave_table);
for (c = 0; c < s->channels; c++)
av_freep(&s->buf[c]);
av_freep(&s->buf);
}
static int config_input(AVFilterLink *inlink)
{
int c;
AVFilterContext *ctx = inlink->dst;
VibratoContext *s = ctx->priv;
s->buf = av_calloc(inlink->ch_layout.nb_channels, sizeof(*s->buf));
if (!s->buf)
return AVERROR(ENOMEM);
s->channels = inlink->ch_layout.nb_channels;
s->buf_size = lrint(inlink->sample_rate * 0.005 + 0.5);
for (c = 0; c < s->channels; c++) {
s->buf[c] = av_malloc_array(s->buf_size, sizeof(*s->buf[c]));
if (!s->buf[c])
return AVERROR(ENOMEM);
}
s->buf_index = 0;
s->wave_table_size = lrint(inlink->sample_rate / s->freq + 0.5);
s->wave_table = av_malloc_array(s->wave_table_size, 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->wave_table_size, 0.0, s->buf_size - 1, 3.0 * M_PI_2);
s->wave_table_index = 0;
return 0;
}
static const AVFilterPad avfilter_af_vibrato_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.config_props = config_input,
.filter_frame = filter_frame,
},
};
const AVFilter ff_af_vibrato = {
.name = "vibrato",
.description = NULL_IF_CONFIG_SMALL("Apply vibrato effect."),
.priv_size = sizeof(VibratoContext),
.priv_class = &vibrato_class,
.uninit = uninit,
FILTER_INPUTS(avfilter_af_vibrato_inputs),
FILTER_OUTPUTS(ff_audio_default_filterpad),
FILTER_SINGLE_SAMPLEFMT(AV_SAMPLE_FMT_DBLP),
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
};
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