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/*
* Copyright (c) 2001-2010 Krzysztof Foltman, Markus Schmidt, Thor Harald Johansen, Vladimir Sadovnikov and others
* Copyright (c) 2015 Paul B Mahol
*
* 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 "libavutil/samplefmt.h"
#include "avfilter.h"
#include "audio.h"
#include "internal.h"
typedef struct CompensationDelayContext {
const AVClass *class;
int distance_mm;
int distance_cm;
int distance_m;
double dry, wet;
int temp;
unsigned delay;
unsigned w_ptr;
unsigned buf_size;
AVFrame *delay_frame;
} CompensationDelayContext;
#define OFFSET(x) offsetof(CompensationDelayContext, x)
#define A (AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM)
static const AVOption compensationdelay_options[] = {
{ "mm", "set mm distance", OFFSET(distance_mm), AV_OPT_TYPE_INT, {.i64=0}, 0, 10, A },
{ "cm", "set cm distance", OFFSET(distance_cm), AV_OPT_TYPE_INT, {.i64=0}, 0, 100, A },
{ "m", "set meter distance", OFFSET(distance_m), AV_OPT_TYPE_INT, {.i64=0}, 0, 100, A },
{ "dry", "set dry amount", OFFSET(dry), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 1, A },
{ "wet", "set wet amount", OFFSET(wet), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, A },
{ "temp", "set temperature °C", OFFSET(temp), AV_OPT_TYPE_INT, {.i64=20}, -50, 50, A },
{ NULL }
};
AVFILTER_DEFINE_CLASS(compensationdelay);
// The maximum distance for options
#define COMP_DELAY_MAX_DISTANCE (100.0 * 100.0 + 100.0 * 1.0 + 1.0)
// The actual speed of sound in normal conditions
#define COMP_DELAY_SOUND_SPEED_KM_H(temp) 1.85325 * (643.95 * sqrt(((temp + 273.15) / 273.15)))
#define COMP_DELAY_SOUND_SPEED_CM_S(temp) (COMP_DELAY_SOUND_SPEED_KM_H(temp) * (1000.0 * 100.0) /* cm/km */ / (60.0 * 60.0) /* s/h */)
#define COMP_DELAY_SOUND_FRONT_DELAY(temp) (1.0 / COMP_DELAY_SOUND_SPEED_CM_S(temp))
// The maximum delay may be reached by this filter
#define COMP_DELAY_MAX_DELAY (COMP_DELAY_MAX_DISTANCE * COMP_DELAY_SOUND_FRONT_DELAY(50))
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
CompensationDelayContext *s = ctx->priv;
unsigned min_size, new_size = 1;
s->delay = (s->distance_m * 100. + s->distance_cm * 1. + s->distance_mm * .1) *
COMP_DELAY_SOUND_FRONT_DELAY(s->temp) * inlink->sample_rate;
min_size = inlink->sample_rate * COMP_DELAY_MAX_DELAY;
while (new_size < min_size)
new_size <<= 1;
s->buf_size = new_size;
s->delay_frame = ff_get_audio_buffer(inlink, s->buf_size);
if (!s->delay_frame)
return AVERROR(ENOMEM);
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
CompensationDelayContext *s = ctx->priv;
const unsigned b_mask = s->buf_size - 1;
const unsigned buf_size = s->buf_size;
const unsigned delay = s->delay;
const double dry = s->dry;
const double wet = s->wet;
unsigned r_ptr, w_ptr = 0;
AVFrame *out;
int n, ch;
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 (ch = 0; ch < inlink->ch_layout.nb_channels; ch++) {
const double *src = (const double *)in->extended_data[ch];
double *dst = (double *)out->extended_data[ch];
double *buffer = (double *)s->delay_frame->extended_data[ch];
w_ptr = s->w_ptr;
r_ptr = (w_ptr + buf_size - delay) & b_mask;
for (n = 0; n < in->nb_samples; n++) {
const double sample = src[n];
buffer[w_ptr] = sample;
dst[n] = dry * sample + wet * buffer[r_ptr];
w_ptr = (w_ptr + 1) & b_mask;
r_ptr = (r_ptr + 1) & b_mask;
}
}
s->w_ptr = w_ptr;
if (ctx->is_disabled) {
av_frame_free(&out);
return ff_filter_frame(outlink, in);
}
av_frame_free(&in);
return ff_filter_frame(outlink, out);
}
static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
char *res, int res_len, int flags)
{
CompensationDelayContext *s = ctx->priv;
AVFilterLink *outlink = ctx->outputs[0];
int ret;
ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
if (ret < 0)
return ret;
s->delay = (s->distance_m * 100. + s->distance_cm * 1. + s->distance_mm * .1) *
COMP_DELAY_SOUND_FRONT_DELAY(s->temp) * outlink->sample_rate;
return 0;
}
static av_cold void uninit(AVFilterContext *ctx)
{
CompensationDelayContext *s = ctx->priv;
av_frame_free(&s->delay_frame);
}
static const AVFilterPad compensationdelay_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.config_props = config_input,
.filter_frame = filter_frame,
},
};
const AVFilter ff_af_compensationdelay = {
.name = "compensationdelay",
.description = NULL_IF_CONFIG_SMALL("Audio Compensation Delay Line."),
.priv_size = sizeof(CompensationDelayContext),
.priv_class = &compensationdelay_class,
.uninit = uninit,
FILTER_INPUTS(compensationdelay_inputs),
FILTER_OUTPUTS(ff_audio_default_filterpad),
FILTER_SINGLE_SAMPLEFMT(AV_SAMPLE_FMT_DBLP),
.process_command = process_command,
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL,
};
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