2 * This file is part of FFmpeg.
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.
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.
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
19 #include "libavutil/channel_layout.h"
20 #include "libavutil/ffmath.h"
21 #include "libavutil/opt.h"
26 typedef struct ASubBoostContext {
47 static int query_formats(AVFilterContext *ctx)
49 AVFilterFormats *formats = NULL;
50 AVFilterChannelLayouts *layouts = NULL;
51 static const enum AVSampleFormat sample_fmts[] = {
57 formats = ff_make_format_list(sample_fmts);
59 return AVERROR(ENOMEM);
60 ret = ff_set_common_formats(ctx, formats);
64 layouts = ff_all_channel_counts();
66 return AVERROR(ENOMEM);
68 ret = ff_set_common_channel_layouts(ctx, layouts);
72 formats = ff_all_samplerates();
73 return ff_set_common_samplerates(ctx, formats);
76 static int get_coeffs(AVFilterContext *ctx)
78 ASubBoostContext *s = ctx->priv;
79 AVFilterLink *inlink = ctx->inputs[0];
80 double w0 = 2 * M_PI * s->cutoff / inlink->sample_rate;
81 double alpha = sin(w0) / 2 * sqrt(2. * (1. / s->slope - 1.) + 2.);
86 s->b0 = (1 - cos(w0)) / 2;
88 s->b2 = (1 - cos(w0)) / 2;
96 s->buffer_samples = inlink->sample_rate * s->delay / 1000;
101 static int config_input(AVFilterLink *inlink)
103 AVFilterContext *ctx = inlink->dst;
104 ASubBoostContext *s = ctx->priv;
106 s->buffer = ff_get_audio_buffer(inlink, inlink->sample_rate / 10);
107 s->i = ff_get_audio_buffer(inlink, 2);
108 s->o = ff_get_audio_buffer(inlink, 2);
109 if (!s->buffer || !s->i || !s->o)
110 return AVERROR(ENOMEM);
112 return get_coeffs(ctx);
115 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
117 AVFilterContext *ctx = inlink->dst;
118 AVFilterLink *outlink = ctx->outputs[0];
119 ASubBoostContext *s = ctx->priv;
120 const float wet = s->wet_gain, dry = s->dry_gain, feedback = s->feedback, decay = s->decay;
124 if (av_frame_is_writable(in)) {
127 out = ff_get_audio_buffer(outlink, in->nb_samples);
130 return AVERROR(ENOMEM);
132 av_frame_copy_props(out, in);
135 for (int ch = 0; ch < in->channels; ch++) {
136 const double *src = (const double *)in->extended_data[ch];
137 double *dst = (double *)out->extended_data[ch];
138 double *buffer = (double *)s->buffer->extended_data[ch];
139 double *ix = (double *)s->i->extended_data[ch];
140 double *ox = (double *)s->o->extended_data[ch];
142 write_pos = s->write_pos;
143 for (int n = 0; n < in->nb_samples; n++) {
146 out_sample = src[n] * s->b0 + ix[0] * s->b1 + ix[1] * s->b2 - ox[0] * s->a1 - ox[1] * s->a2;
152 buffer[write_pos] = buffer[write_pos] * decay + out_sample * feedback;
153 dst[n] = src[n] * dry + buffer[write_pos] * wet;
155 if (++write_pos >= s->buffer_samples)
160 s->write_pos = write_pos;
164 return ff_filter_frame(outlink, out);
167 static av_cold void uninit(AVFilterContext *ctx)
169 ASubBoostContext *s = ctx->priv;
171 av_frame_free(&s->buffer);
172 av_frame_free(&s->i);
173 av_frame_free(&s->o);
176 static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
177 char *res, int res_len, int flags)
181 ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
185 return get_coeffs(ctx);
188 #define OFFSET(x) offsetof(ASubBoostContext, x)
189 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
191 static const AVOption asubboost_options[] = {
192 { "dry", "set dry gain", OFFSET(dry_gain), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, FLAGS },
193 { "wet", "set wet gain", OFFSET(wet_gain), AV_OPT_TYPE_DOUBLE, {.dbl=0.8}, 0, 1, FLAGS },
194 { "decay", "set decay", OFFSET(decay), AV_OPT_TYPE_DOUBLE, {.dbl=0.7}, 0, 1, FLAGS },
195 { "feedback", "set feedback", OFFSET(feedback), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, FLAGS },
196 { "cutoff", "set cutoff", OFFSET(cutoff), AV_OPT_TYPE_DOUBLE, {.dbl=100}, 50, 900, FLAGS },
197 { "slope", "set slope", OFFSET(slope), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0.0001, 1, FLAGS },
198 { "delay", "set delay", OFFSET(delay), AV_OPT_TYPE_DOUBLE, {.dbl=20}, 1, 100, FLAGS },
202 AVFILTER_DEFINE_CLASS(asubboost);
204 static const AVFilterPad inputs[] = {
207 .type = AVMEDIA_TYPE_AUDIO,
208 .filter_frame = filter_frame,
209 .config_props = config_input,
214 static const AVFilterPad outputs[] = {
217 .type = AVMEDIA_TYPE_AUDIO,
222 AVFilter ff_af_asubboost = {
224 .description = NULL_IF_CONFIG_SMALL("Boost subwoofer frequencies."),
225 .query_formats = query_formats,
226 .priv_size = sizeof(ASubBoostContext),
227 .priv_class = &asubboost_class,
231 .process_command = process_command,