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/channel_layout.h"
20 #include "libavutil/ffmath.h"
21 #include "libavutil/opt.h"
22 #include "avfilter.h"
23 #include "audio.h"
24 #include "formats.h"
25
26 typedef struct ASubBoostContext {
27 const AVClass *class;
28
29 double dry_gain;
30 double wet_gain;
31 double feedback;
32 double max_boost;
33 double decay;
34 double delay;
35 double cutoff;
36 double slope;
37
38 double a0, a1, a2;
39 double b0, b1, b2;
40
41 char *ch_layout_str;
42 AVChannelLayout ch_layout;
43
44 int *write_pos;
45 int buffer_samples;
46
47 AVFrame *w;
48 AVFrame *buffer;
49 } ASubBoostContext;
50
get_coeffs(AVFilterContext * ctx)51 static int get_coeffs(AVFilterContext *ctx)
52 {
53 ASubBoostContext *s = ctx->priv;
54 AVFilterLink *inlink = ctx->inputs[0];
55 double w0 = 2 * M_PI * s->cutoff / inlink->sample_rate;
56 double alpha = sin(w0) / 2 * sqrt(2. * (1. / s->slope - 1.) + 2.);
57
58 s->a0 = 1 + alpha;
59 s->a1 = -2 * cos(w0);
60 s->a2 = 1 - alpha;
61 s->b0 = (1 - cos(w0)) / 2;
62 s->b1 = 1 - cos(w0);
63 s->b2 = (1 - cos(w0)) / 2;
64
65 s->a1 /= s->a0;
66 s->a2 /= s->a0;
67 s->b0 /= s->a0;
68 s->b1 /= s->a0;
69 s->b2 /= s->a0;
70
71 s->buffer_samples = inlink->sample_rate * s->delay / 1000;
72
73 return 0;
74 }
75
config_input(AVFilterLink * inlink)76 static int config_input(AVFilterLink *inlink)
77 {
78 AVFilterContext *ctx = inlink->dst;
79 ASubBoostContext *s = ctx->priv;
80
81 s->buffer = ff_get_audio_buffer(inlink, inlink->sample_rate / 10);
82 s->w = ff_get_audio_buffer(inlink, 3);
83 s->write_pos = av_calloc(inlink->ch_layout.nb_channels, sizeof(*s->write_pos));
84 if (!s->buffer || !s->w || !s->write_pos)
85 return AVERROR(ENOMEM);
86
87 return get_coeffs(ctx);
88 }
89
90 typedef struct ThreadData {
91 AVFrame *in, *out;
92 } ThreadData;
93
filter_channels(AVFilterContext * ctx,void * arg,int jobnr,int nb_jobs)94 static int filter_channels(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
95 {
96 ASubBoostContext *s = ctx->priv;
97 ThreadData *td = arg;
98 AVFrame *out = td->out;
99 AVFrame *in = td->in;
100 const double mix = ctx->is_disabled ? 0. : 1.;
101 const double wet = ctx->is_disabled ? 1. : s->wet_gain;
102 const double dry = ctx->is_disabled ? 1. : s->dry_gain;
103 const double feedback = s->feedback, decay = s->decay;
104 const double max_boost = s->max_boost;
105 const double b0 = s->b0;
106 const double b1 = s->b1;
107 const double b2 = s->b2;
108 const double a1 = -s->a1;
109 const double a2 = -s->a2;
110 const int start = (in->ch_layout.nb_channels * jobnr) / nb_jobs;
111 const int end = (in->ch_layout.nb_channels * (jobnr+1)) / nb_jobs;
112 const int buffer_samples = s->buffer_samples;
113
114 for (int ch = start; ch < end; ch++) {
115 const double *src = (const double *)in->extended_data[ch];
116 double *dst = (double *)out->extended_data[ch];
117 double *buffer = (double *)s->buffer->extended_data[ch];
118 double *w = (double *)s->w->extended_data[ch];
119 int write_pos = s->write_pos[ch];
120 enum AVChannel channel = av_channel_layout_channel_from_index(&in->ch_layout, ch);
121 const int bypass = av_channel_layout_index_from_channel(&s->ch_layout, channel) < 0;
122 const double a = 0.00001;
123 const double b = 1. - a;
124
125 if (bypass) {
126 if (in != out)
127 memcpy(out->extended_data[ch], in->extended_data[ch],
128 in->nb_samples * sizeof(double));
129 continue;
130 }
131
132 for (int n = 0; n < in->nb_samples; n++) {
133 double out_sample, boost;
134
135 out_sample = src[n] * b0 + w[0];
136 w[0] = b1 * src[n] + w[1] + a1 * out_sample;
137 w[1] = b2 * src[n] + a2 * out_sample;
138
139 buffer[write_pos] = buffer[write_pos] * decay + out_sample * feedback;
140 boost = av_clipd((1. - (fabs(src[n] * dry))) / fabs(buffer[write_pos]), 0., max_boost);
141 w[2] = boost > w[2] ? w[2] * b + a * boost : w[2] * a + b * boost;
142 w[2] = av_clipd(w[2], 0., max_boost);
143 dst[n] = (src[n] * dry + w[2] * buffer[write_pos] * mix) * wet;
144
145 if (++write_pos >= buffer_samples)
146 write_pos = 0;
147 }
148
149 s->write_pos[ch] = write_pos;
150 }
151
152 return 0;
153 }
154
filter_frame(AVFilterLink * inlink,AVFrame * in)155 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
156 {
157 AVFilterContext *ctx = inlink->dst;
158 ASubBoostContext *s = ctx->priv;
159 AVFilterLink *outlink = ctx->outputs[0];
160 ThreadData td;
161 AVFrame *out;
162 int ret;
163
164 ret = av_channel_layout_copy(&s->ch_layout, &inlink->ch_layout);
165 if (ret < 0)
166 return ret;
167 if (strcmp(s->ch_layout_str, "all"))
168 av_channel_layout_from_string(&s->ch_layout,
169 s->ch_layout_str);
170
171 if (av_frame_is_writable(in)) {
172 out = in;
173 } else {
174 out = ff_get_audio_buffer(outlink, in->nb_samples);
175 if (!out) {
176 av_frame_free(&in);
177 return AVERROR(ENOMEM);
178 }
179 av_frame_copy_props(out, in);
180 }
181
182 td.in = in; td.out = out;
183 ff_filter_execute(ctx, filter_channels, &td, NULL,
184 FFMIN(inlink->ch_layout.nb_channels, ff_filter_get_nb_threads(ctx)));
185
186 if (out != in)
187 av_frame_free(&in);
188 return ff_filter_frame(outlink, out);
189 }
190
uninit(AVFilterContext * ctx)191 static av_cold void uninit(AVFilterContext *ctx)
192 {
193 ASubBoostContext *s = ctx->priv;
194
195 av_channel_layout_uninit(&s->ch_layout);
196 av_frame_free(&s->buffer);
197 av_frame_free(&s->w);
198 av_freep(&s->write_pos);
199 }
200
process_command(AVFilterContext * ctx,const char * cmd,const char * args,char * res,int res_len,int flags)201 static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
202 char *res, int res_len, int flags)
203 {
204 int ret;
205
206 ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
207 if (ret < 0)
208 return ret;
209
210 return get_coeffs(ctx);
211 }
212
213 #define OFFSET(x) offsetof(ASubBoostContext, x)
214 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
215
216 static const AVOption asubboost_options[] = {
217 { "dry", "set dry gain", OFFSET(dry_gain), AV_OPT_TYPE_DOUBLE, {.dbl=1.0}, 0, 1, FLAGS },
218 { "wet", "set wet gain", OFFSET(wet_gain), AV_OPT_TYPE_DOUBLE, {.dbl=1.0}, 0, 1, FLAGS },
219 { "boost", "set max boost",OFFSET(max_boost),AV_OPT_TYPE_DOUBLE, {.dbl=2.0}, 1, 12, FLAGS },
220 { "decay", "set decay", OFFSET(decay), AV_OPT_TYPE_DOUBLE, {.dbl=0.0}, 0, 1, FLAGS },
221 { "feedback", "set feedback", OFFSET(feedback), AV_OPT_TYPE_DOUBLE, {.dbl=0.9}, 0, 1, FLAGS },
222 { "cutoff", "set cutoff", OFFSET(cutoff), AV_OPT_TYPE_DOUBLE, {.dbl=100}, 50, 900, FLAGS },
223 { "slope", "set slope", OFFSET(slope), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0.0001, 1, FLAGS },
224 { "delay", "set delay", OFFSET(delay), AV_OPT_TYPE_DOUBLE, {.dbl=20}, 1, 100, FLAGS },
225 { "channels", "set channels to filter", OFFSET(ch_layout_str), AV_OPT_TYPE_STRING, {.str="all"}, 0, 0, FLAGS },
226 { NULL }
227 };
228
229 AVFILTER_DEFINE_CLASS(asubboost);
230
231 static const AVFilterPad inputs[] = {
232 {
233 .name = "default",
234 .type = AVMEDIA_TYPE_AUDIO,
235 .filter_frame = filter_frame,
236 .config_props = config_input,
237 },
238 };
239
240 static const AVFilterPad outputs[] = {
241 {
242 .name = "default",
243 .type = AVMEDIA_TYPE_AUDIO,
244 },
245 };
246
247 const AVFilter ff_af_asubboost = {
248 .name = "asubboost",
249 .description = NULL_IF_CONFIG_SMALL("Boost subwoofer frequencies."),
250 .priv_size = sizeof(ASubBoostContext),
251 .priv_class = &asubboost_class,
252 .uninit = uninit,
253 FILTER_INPUTS(inputs),
254 FILTER_OUTPUTS(outputs),
255 FILTER_SINGLE_SAMPLEFMT(AV_SAMPLE_FMT_DBLP),
256 .process_command = process_command,
257 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL |
258 AVFILTER_FLAG_SLICE_THREADS,
259 };
260