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path: root/libavfilter/af_compensationdelay.c (plain)
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1/*
2 * Copyright (c) 2001-2010 Krzysztof Foltman, Markus Schmidt, Thor Harald Johansen, Vladimir Sadovnikov and others
3 * Copyright (c) 2015 Paul B Mahol
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "libavutil/opt.h"
23#include "libavutil/samplefmt.h"
24#include "avfilter.h"
25#include "audio.h"
26#include "internal.h"
27
28typedef struct CompensationDelayContext {
29 const AVClass *class;
30 int distance_mm;
31 int distance_cm;
32 int distance_m;
33 double dry, wet;
34 int temp;
35
36 unsigned delay;
37 unsigned w_ptr;
38 unsigned buf_size;
39 AVFrame *delay_frame;
40} CompensationDelayContext;
41
42#define OFFSET(x) offsetof(CompensationDelayContext, x)
43#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
44
45static const AVOption compensationdelay_options[] = {
46 { "mm", "set mm distance", OFFSET(distance_mm), AV_OPT_TYPE_INT, {.i64=0}, 0, 10, A },
47 { "cm", "set cm distance", OFFSET(distance_cm), AV_OPT_TYPE_INT, {.i64=0}, 0, 100, A },
48 { "m", "set meter distance", OFFSET(distance_m), AV_OPT_TYPE_INT, {.i64=0}, 0, 100, A },
49 { "dry", "set dry amount", OFFSET(dry), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 1, A },
50 { "wet", "set wet amount", OFFSET(wet), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, A },
51 { "temp", "set temperature °C", OFFSET(temp), AV_OPT_TYPE_INT, {.i64=20}, -50, 50, A },
52 { NULL }
53};
54
55AVFILTER_DEFINE_CLASS(compensationdelay);
56
57// The maximum distance for options
58#define COMP_DELAY_MAX_DISTANCE (100.0 * 100.0 + 100.0 * 1.0 + 1.0)
59// The actual speed of sound in normal conditions
60#define COMP_DELAY_SOUND_SPEED_KM_H(temp) 1.85325 * (643.95 * sqrt(((temp + 273.15) / 273.15)))
61#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 */)
62#define COMP_DELAY_SOUND_FRONT_DELAY(temp) (1.0 / COMP_DELAY_SOUND_SPEED_CM_S(temp))
63// The maximum delay may be reached by this filter
64#define COMP_DELAY_MAX_DELAY (COMP_DELAY_MAX_DISTANCE * COMP_DELAY_SOUND_FRONT_DELAY(50))
65
66static int query_formats(AVFilterContext *ctx)
67{
68 AVFilterChannelLayouts *layouts;
69 AVFilterFormats *formats;
70 static const enum AVSampleFormat sample_fmts[] = {
71 AV_SAMPLE_FMT_DBLP,
72 AV_SAMPLE_FMT_NONE
73 };
74 int ret;
75
76 layouts = ff_all_channel_counts();
77 if (!layouts)
78 return AVERROR(ENOMEM);
79 ret = ff_set_common_channel_layouts(ctx, layouts);
80 if (ret < 0)
81 return ret;
82
83 formats = ff_make_format_list(sample_fmts);
84 if (!formats)
85 return AVERROR(ENOMEM);
86 ret = ff_set_common_formats(ctx, formats);
87 if (ret < 0)
88 return ret;
89
90 formats = ff_all_samplerates();
91 if (!formats)
92 return AVERROR(ENOMEM);
93 return ff_set_common_samplerates(ctx, formats);
94}
95
96static int config_input(AVFilterLink *inlink)
97{
98 AVFilterContext *ctx = inlink->dst;
99 CompensationDelayContext *s = ctx->priv;
100 unsigned min_size, new_size = 1;
101
102 s->delay = (s->distance_m * 100. + s->distance_cm * 1. + s->distance_mm * .1) *
103 COMP_DELAY_SOUND_FRONT_DELAY(s->temp) * inlink->sample_rate;
104 min_size = inlink->sample_rate * COMP_DELAY_MAX_DELAY;
105
106 while (new_size < min_size)
107 new_size <<= 1;
108
109 s->delay_frame = av_frame_alloc();
110 if (!s->delay_frame)
111 return AVERROR(ENOMEM);
112
113 s->buf_size = new_size;
114 s->delay_frame->format = inlink->format;
115 s->delay_frame->nb_samples = new_size;
116 s->delay_frame->channel_layout = inlink->channel_layout;
117
118 return av_frame_get_buffer(s->delay_frame, 32);
119}
120
121static int filter_frame(AVFilterLink *inlink, AVFrame *in)
122{
123 AVFilterContext *ctx = inlink->dst;
124 CompensationDelayContext *s = ctx->priv;
125 const unsigned b_mask = s->buf_size - 1;
126 const unsigned buf_size = s->buf_size;
127 const unsigned delay = s->delay;
128 const double dry = s->dry;
129 const double wet = s->wet;
130 unsigned r_ptr, w_ptr;
131 AVFrame *out;
132 int n, ch;
133
134 out = ff_get_audio_buffer(inlink, in->nb_samples);
135 if (!out) {
136 av_frame_free(&in);
137 return AVERROR(ENOMEM);
138 }
139 av_frame_copy_props(out, in);
140
141 for (ch = 0; ch < inlink->channels; ch++) {
142 const double *src = (const double *)in->extended_data[ch];
143 double *dst = (double *)out->extended_data[ch];
144 double *buffer = (double *)s->delay_frame->extended_data[ch];
145
146 w_ptr = s->w_ptr;
147 r_ptr = (w_ptr + buf_size - delay) & b_mask;
148
149 for (n = 0; n < in->nb_samples; n++) {
150 const double sample = src[n];
151
152 buffer[w_ptr] = sample;
153 dst[n] = dry * sample + wet * buffer[r_ptr];
154 w_ptr = (w_ptr + 1) & b_mask;
155 r_ptr = (r_ptr + 1) & b_mask;
156 }
157 }
158 s->w_ptr = w_ptr;
159
160 av_frame_free(&in);
161 return ff_filter_frame(ctx->outputs[0], out);
162}
163
164static av_cold void uninit(AVFilterContext *ctx)
165{
166 CompensationDelayContext *s = ctx->priv;
167
168 av_frame_free(&s->delay_frame);
169}
170
171static const AVFilterPad compensationdelay_inputs[] = {
172 {
173 .name = "default",
174 .type = AVMEDIA_TYPE_AUDIO,
175 .config_props = config_input,
176 .filter_frame = filter_frame,
177 },
178 { NULL }
179};
180
181static const AVFilterPad compensationdelay_outputs[] = {
182 {
183 .name = "default",
184 .type = AVMEDIA_TYPE_AUDIO,
185 },
186 { NULL }
187};
188
189AVFilter ff_af_compensationdelay = {
190 .name = "compensationdelay",
191 .description = NULL_IF_CONFIG_SMALL("Audio Compensation Delay Line."),
192 .query_formats = query_formats,
193 .priv_size = sizeof(CompensationDelayContext),
194 .priv_class = &compensationdelay_class,
195 .uninit = uninit,
196 .inputs = compensationdelay_inputs,
197 .outputs = compensationdelay_outputs,
198};
199
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