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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 
28 typedef 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 
45 static 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 
55 AVFILTER_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 
query_formats(AVFilterContext * ctx)66 static 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 
config_input(AVFilterLink * inlink)96 static 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, 0);
119 }
120 
filter_frame(AVFilterLink * inlink,AVFrame * in)121 static 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 = 0;
131     AVFrame *out;
132     int n, ch;
133 
134     out = ff_get_audio_buffer(ctx->outputs[0], 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 
uninit(AVFilterContext * ctx)164 static av_cold void uninit(AVFilterContext *ctx)
165 {
166     CompensationDelayContext *s = ctx->priv;
167 
168     av_frame_free(&s->delay_frame);
169 }
170 
171 static 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 
181 static const AVFilterPad compensationdelay_outputs[] = {
182     {
183         .name = "default",
184         .type = AVMEDIA_TYPE_AUDIO,
185     },
186     { NULL }
187 };
188 
189 AVFilter 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