2 * Copyright (C) 2001-2010 Krzysztof Foltman, Markus Schmidt, Thor Harald Johansen, Damien Zammit
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 #include "libavutil/channel_layout.h"
22 #include "libavutil/opt.h"
28 typedef struct AudioGateContext {
51 #define OFFSET(x) offsetof(AudioGateContext, x)
52 #define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
54 static const AVOption agate_options[] = {
55 { "level_in", "set input level", OFFSET(level_in), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0.015625, 64, A },
56 { "range", "set max gain reduction", OFFSET(range), AV_OPT_TYPE_DOUBLE, {.dbl=0.06125}, 0, 1, A },
57 { "threshold", "set threshold", OFFSET(threshold), AV_OPT_TYPE_DOUBLE, {.dbl=0.125}, 0, 1, A },
58 { "ratio", "set ratio", OFFSET(ratio), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 1, 9000, A },
59 { "attack", "set attack", OFFSET(attack), AV_OPT_TYPE_DOUBLE, {.dbl=20}, 0.01, 9000, A },
60 { "release", "set release", OFFSET(release), AV_OPT_TYPE_DOUBLE, {.dbl=250}, 0.01, 9000, A },
61 { "makeup", "set makeup gain", OFFSET(makeup), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 1, 64, A },
62 { "knee", "set knee", OFFSET(knee), AV_OPT_TYPE_DOUBLE, {.dbl=2.828427125}, 1, 8, A },
63 { "detection", "set detection", OFFSET(detection), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, A, "detection" },
64 { "peak", 0, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, A, "detection" },
65 { "rms", 0, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, A, "detection" },
66 { "link", "set link", OFFSET(link), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, A, "link" },
67 { "average", 0, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, A, "link" },
68 { "maximum", 0, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, A, "link" },
72 AVFILTER_DEFINE_CLASS(agate);
74 static int query_formats(AVFilterContext *ctx)
76 AVFilterFormats *formats = NULL;
77 AVFilterChannelLayouts *layouts;
80 if ((ret = ff_add_format(&formats, AV_SAMPLE_FMT_DBL)) < 0)
82 ret = ff_set_common_formats(ctx, formats);
86 layouts = ff_all_channel_counts();
88 return AVERROR(ENOMEM);
89 ret = ff_set_common_channel_layouts(ctx, layouts);
93 formats = ff_all_samplerates();
95 return AVERROR(ENOMEM);
97 return ff_set_common_samplerates(ctx, formats);
100 static int config_input(AVFilterLink *inlink)
102 AVFilterContext *ctx = inlink->dst;
103 AudioGateContext *s = ctx->priv;
104 double lin_threshold = s->threshold;
105 double lin_knee_sqrt = sqrt(s->knee);
106 double lin_knee_start;
109 lin_threshold *= lin_threshold;
111 s->attack_coeff = FFMIN(1., 1. / (s->attack * inlink->sample_rate / 4000.));
112 s->release_coeff = FFMIN(1., 1. / (s->release * inlink->sample_rate / 4000.));
113 s->lin_knee_stop = lin_threshold * lin_knee_sqrt;
114 lin_knee_start = lin_threshold / lin_knee_sqrt;
115 s->thres = log(lin_threshold);
116 s->knee_start = log(lin_knee_start);
117 s->knee_stop = log(s->lin_knee_stop);
122 // A fake infinity value (because real infinity may break some hosts)
123 #define FAKE_INFINITY (65536.0 * 65536.0)
125 // Check for infinity (with appropriate-ish tolerance)
126 #define IS_FAKE_INFINITY(value) (fabs(value-FAKE_INFINITY) < 1.0)
128 static double output_gain(double lin_slope, double ratio, double thres,
129 double knee, double knee_start, double knee_stop,
130 double lin_knee_stop, double range)
132 if (lin_slope < lin_knee_stop) {
133 double slope = log(lin_slope);
134 double tratio = ratio;
138 if (IS_FAKE_INFINITY(ratio))
140 gain = (slope - thres) * tratio + thres;
143 if (knee > 1. && slope > knee_start) {
144 gain = hermite_interpolation(slope, knee_start, knee_stop, ((knee_start - thres) * tratio + thres), knee_stop, delta, 1.);
146 return FFMAX(range, exp(gain - slope));
152 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
154 AVFilterContext *ctx = inlink->dst;
155 AVFilterLink *outlink = ctx->outputs[0];
156 AudioGateContext *s = ctx->priv;
157 const double *src = (const double *)in->data[0];
158 const double makeup = s->makeup;
159 const double attack_coeff = s->attack_coeff;
160 const double release_coeff = s->release_coeff;
161 const double level_in = s->level_in;
166 if (av_frame_is_writable(in)) {
169 out = ff_get_audio_buffer(inlink, in->nb_samples);
172 return AVERROR(ENOMEM);
174 av_frame_copy_props(out, in);
176 dst = (double *)out->data[0];
178 for (n = 0; n < in->nb_samples; n++, src += inlink->channels, dst += inlink->channels) {
179 double abs_sample = fabs(src[0]), gain = 1.0;
181 for (c = 0; c < inlink->channels; c++)
182 dst[c] = src[c] * level_in;
185 for (c = 1; c < inlink->channels; c++)
186 abs_sample = FFMAX(fabs(src[c]), abs_sample);
188 for (c = 1; c < inlink->channels; c++)
189 abs_sample += fabs(src[c]);
191 abs_sample /= inlink->channels;
195 abs_sample *= abs_sample;
197 s->lin_slope += (abs_sample - s->lin_slope) * (abs_sample > s->lin_slope ? attack_coeff : release_coeff);
198 if (s->lin_slope > 0.0)
199 gain = output_gain(s->lin_slope, s->ratio, s->thres,
200 s->knee, s->knee_start, s->knee_stop,
201 s->lin_knee_stop, s->range);
203 for (c = 0; c < inlink->channels; c++)
204 dst[c] *= gain * makeup;
209 return ff_filter_frame(outlink, out);
212 static const AVFilterPad inputs[] = {
215 .type = AVMEDIA_TYPE_AUDIO,
216 .filter_frame = filter_frame,
217 .config_props = config_input,
222 static const AVFilterPad outputs[] = {
225 .type = AVMEDIA_TYPE_AUDIO,
230 AVFilter ff_af_agate = {
232 .description = NULL_IF_CONFIG_SMALL("Audio gate."),
233 .query_formats = query_formats,
234 .priv_size = sizeof(AudioGateContext),
235 .priv_class = &agate_class,