1 /*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 #include "libavutil/ffmath.h"
20 #include "libavutil/opt.h"
21 #include "avfilter.h"
22 #include "audio.h"
23 #include "formats.h"
24
25 typedef struct AudioDynamicSmoothContext {
26 const AVClass *class;
27
28 double sensitivity;
29 double basefreq;
30
31 AVFrame *coeffs;
32 } AudioDynamicSmoothContext;
33
config_input(AVFilterLink *inlink)34 static int config_input(AVFilterLink *inlink)
35 {
36 AVFilterContext *ctx = inlink->dst;
37 AudioDynamicSmoothContext *s = ctx->priv;
38
39 s->coeffs = ff_get_audio_buffer(inlink, 3);
40 if (!s->coeffs)
41 return AVERROR(ENOMEM);
42
43 return 0;
44 }
45
filter_frame(AVFilterLink *inlink, AVFrame *in)46 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
47 {
48 AVFilterContext *ctx = inlink->dst;
49 AVFilterLink *outlink = ctx->outputs[0];
50 AudioDynamicSmoothContext *s = ctx->priv;
51 const double sensitivity = s->sensitivity;
52 const double wc = s->basefreq / in->sample_rate;
53 AVFrame *out;
54
55 if (av_frame_is_writable(in)) {
56 out = in;
57 } else {
58 out = ff_get_audio_buffer(outlink, in->nb_samples);
59 if (!out) {
60 av_frame_free(&in);
61 return AVERROR(ENOMEM);
62 }
63 av_frame_copy_props(out, in);
64 }
65
66 for (int ch = 0; ch < out->ch_layout.nb_channels; ch++) {
67 const double *src = (const double *)in->extended_data[ch];
68 double *dst = (double *)out->extended_data[ch];
69 double *coeffs = (double *)s->coeffs->extended_data[ch];
70 double low1 = coeffs[0];
71 double low2 = coeffs[1];
72 double inz = coeffs[2];
73
74 for (int n = 0; n < out->nb_samples; n++) {
75 double low1z = low1;
76 double low2z = low2;
77 double bandz = low2z - low1z;
78 double wd = wc + sensitivity * fabs(bandz);
79 double g = fmin(1., wd * (5.9948827 + wd * (-11.969296 + wd * 15.959062)));
80
81 low1 = low1z + g * (0.5 * (src[n] + inz) - low1z);
82 low2 = low2z + g * (0.5 * (low1 + low1z) - low2z);
83 inz = src[n];
84 dst[n] = ctx->is_disabled ? src[n] : low2;
85 }
86
87 coeffs[0] = low1;
88 coeffs[1] = low2;
89 coeffs[2] = inz;
90 }
91
92 if (out != in)
93 av_frame_free(&in);
94 return ff_filter_frame(outlink, out);
95 }
96
uninit(AVFilterContext *ctx)97 static av_cold void uninit(AVFilterContext *ctx)
98 {
99 AudioDynamicSmoothContext *s = ctx->priv;
100
101 av_frame_free(&s->coeffs);
102 }
103
104 #define OFFSET(x) offsetof(AudioDynamicSmoothContext, x)
105 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
106
107 static const AVOption adynamicsmooth_options[] = {
108 { "sensitivity", "set smooth sensitivity", OFFSET(sensitivity), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, 1000000, FLAGS },
109 { "basefreq", "set base frequency", OFFSET(basefreq), AV_OPT_TYPE_DOUBLE, {.dbl=22050}, 2, 1000000, FLAGS },
110 { NULL }
111 };
112
113 AVFILTER_DEFINE_CLASS(adynamicsmooth);
114
115 static const AVFilterPad inputs[] = {
116 {
117 .name = "default",
118 .type = AVMEDIA_TYPE_AUDIO,
119 .filter_frame = filter_frame,
120 .config_props = config_input,
121 },
122 };
123
124 static const AVFilterPad outputs[] = {
125 {
126 .name = "default",
127 .type = AVMEDIA_TYPE_AUDIO,
128 },
129 };
130
131 const AVFilter ff_af_adynamicsmooth = {
132 .name = "adynamicsmooth",
133 .description = NULL_IF_CONFIG_SMALL("Apply Dynamic Smoothing of input audio."),
134 .priv_size = sizeof(AudioDynamicSmoothContext),
135 .priv_class = &adynamicsmooth_class,
136 .uninit = uninit,
137 FILTER_INPUTS(inputs),
138 FILTER_OUTPUTS(outputs),
139 FILTER_SINGLE_SAMPLEFMT(AV_SAMPLE_FMT_DBLP),
140 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL,
141 .process_command = ff_filter_process_command,
142 };
143