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 "filters.h"
25 #include "formats.h"
26
27 typedef struct CrossfeedContext {
28 const AVClass *class;
29
30 double range;
31 double strength;
32 double slope;
33 double level_in;
34 double level_out;
35 int block_samples;
36 int block_size;
37
38 double a0, a1, a2;
39 double b0, b1, b2;
40
41 double w1, w2;
42
43 int64_t pts;
44 int nb_samples;
45
46 double *mid;
47 double *side[3];
48 } CrossfeedContext;
49
query_formats(AVFilterContext * ctx)50 static int query_formats(AVFilterContext *ctx)
51 {
52 AVFilterFormats *formats = NULL;
53 AVFilterChannelLayouts *layout = NULL;
54 int ret;
55
56 if ((ret = ff_add_format (&formats, AV_SAMPLE_FMT_DBL )) < 0 ||
57 (ret = ff_set_common_formats (ctx , formats )) < 0 ||
58 (ret = ff_add_channel_layout (&layout , &(AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO)) < 0 ||
59 (ret = ff_set_common_channel_layouts (ctx , layout )) < 0 ||
60 (ret = ff_set_common_all_samplerates (ctx )) < 0)
61 return ret;
62
63 return 0;
64 }
65
config_input(AVFilterLink * inlink)66 static int config_input(AVFilterLink *inlink)
67 {
68 AVFilterContext *ctx = inlink->dst;
69 CrossfeedContext *s = ctx->priv;
70 double A = ff_exp10(s->strength * -30 / 40);
71 double w0 = 2 * M_PI * (1. - s->range) * 2100 / inlink->sample_rate;
72 double alpha;
73
74 alpha = sin(w0) / 2 * sqrt((A + 1 / A) * (1 / s->slope - 1) + 2);
75
76 s->a0 = (A + 1) + (A - 1) * cos(w0) + 2 * sqrt(A) * alpha;
77 s->a1 = -2 * ((A - 1) + (A + 1) * cos(w0));
78 s->a2 = (A + 1) + (A - 1) * cos(w0) - 2 * sqrt(A) * alpha;
79 s->b0 = A * ((A + 1) - (A - 1) * cos(w0) + 2 * sqrt(A) * alpha);
80 s->b1 = 2 * A * ((A - 1) - (A + 1) * cos(w0));
81 s->b2 = A * ((A + 1) - (A - 1) * cos(w0) - 2 * sqrt(A) * alpha);
82
83 s->a1 /= s->a0;
84 s->a2 /= s->a0;
85 s->b0 /= s->a0;
86 s->b1 /= s->a0;
87 s->b2 /= s->a0;
88
89 if (s->block_samples == 0 && s->block_size > 0) {
90 s->block_samples = s->block_size;
91 s->mid = av_calloc(s->block_samples * 2, sizeof(*s->mid));
92 for (int i = 0; i < 3; i++) {
93 s->side[i] = av_calloc(s->block_samples * 2, sizeof(*s->side[0]));
94 if (!s->side[i])
95 return AVERROR(ENOMEM);
96 }
97 }
98
99 return 0;
100 }
101
reverse_samples(double * dst,const double * src,int nb_samples)102 static void reverse_samples(double *dst, const double *src,
103 int nb_samples)
104 {
105 for (int i = 0, j = nb_samples - 1; i < nb_samples; i++, j--)
106 dst[i] = src[j];
107 }
108
filter_samples(double * dst,const double * src,int nb_samples,double b0,double b1,double b2,double a1,double a2,double * sw1,double * sw2)109 static void filter_samples(double *dst, const double *src,
110 int nb_samples,
111 double b0, double b1, double b2,
112 double a1, double a2,
113 double *sw1, double *sw2)
114 {
115 double w1 = *sw1;
116 double w2 = *sw2;
117
118 for (int n = 0; n < nb_samples; n++) {
119 double side = src[n];
120 double oside = side * b0 + w1;
121
122 w1 = b1 * side + w2 + a1 * oside;
123 w2 = b2 * side + a2 * oside;
124
125 dst[n] = oside;
126 }
127
128 *sw1 = w1;
129 *sw2 = w2;
130 }
131
filter_frame(AVFilterLink * inlink,AVFrame * in,int eof)132 static int filter_frame(AVFilterLink *inlink, AVFrame *in, int eof)
133 {
134 AVFilterContext *ctx = inlink->dst;
135 AVFilterLink *outlink = ctx->outputs[0];
136 CrossfeedContext *s = ctx->priv;
137 const double *src = (const double *)in->data[0];
138 const double level_in = s->level_in;
139 const double level_out = s->level_out;
140 const double b0 = s->b0;
141 const double b1 = s->b1;
142 const double b2 = s->b2;
143 const double a1 = -s->a1;
144 const double a2 = -s->a2;
145 AVFrame *out;
146 int drop = 0;
147 double *dst;
148
149 if (av_frame_is_writable(in) && s->block_samples == 0) {
150 out = in;
151 } else {
152 out = ff_get_audio_buffer(outlink, s->block_samples > 0 ? s->block_samples : in->nb_samples);
153 if (!out) {
154 av_frame_free(&in);
155 return AVERROR(ENOMEM);
156 }
157 av_frame_copy_props(out, in);
158 }
159 dst = (double *)out->data[0];
160
161 if (s->block_samples > 0 && s->pts == AV_NOPTS_VALUE)
162 drop = 1;
163
164 if (s->block_samples == 0) {
165 double w1 = s->w1;
166 double w2 = s->w2;
167
168 for (int n = 0; n < out->nb_samples; n++, src += 2, dst += 2) {
169 double mid = (src[0] + src[1]) * level_in * .5;
170 double side = (src[0] - src[1]) * level_in * .5;
171 double oside = side * b0 + w1;
172
173 w1 = b1 * side + w2 + a1 * oside;
174 w2 = b2 * side + a2 * oside;
175
176 if (ctx->is_disabled) {
177 dst[0] = src[0];
178 dst[1] = src[1];
179 } else {
180 dst[0] = (mid + oside) * level_out;
181 dst[1] = (mid - oside) * level_out;
182 }
183 }
184
185 s->w1 = w1;
186 s->w2 = w2;
187 } else if (eof) {
188 const double *src = (const double *)in->data[0];
189 double *ssrc = s->side[1] + s->block_samples;
190 double *msrc = s->mid;
191
192 for (int n = 0; n < out->nb_samples; n++, src += 2, dst += 2) {
193 if (ctx->is_disabled) {
194 dst[0] = src[0];
195 dst[1] = src[1];
196 } else {
197 dst[0] = (msrc[n] + ssrc[n]) * level_out;
198 dst[1] = (msrc[n] - ssrc[n]) * level_out;
199 }
200 }
201 } else {
202 double *mdst = s->mid + s->block_samples;
203 double *sdst = s->side[0] + s->block_samples;
204 double *ssrc = s->side[0];
205 double *msrc = s->mid;
206 double w1 = s->w1;
207 double w2 = s->w2;
208
209 for (int n = 0; n < out->nb_samples; n++, src += 2) {
210 mdst[n] = (src[0] + src[1]) * level_in * .5;
211 sdst[n] = (src[0] - src[1]) * level_in * .5;
212 }
213
214 sdst = s->side[1];
215 filter_samples(sdst, ssrc, s->block_samples,
216 b0, b1, b2, a1, a2,
217 &w1, &w2);
218 s->w1 = w1;
219 s->w2 = w2;
220
221 ssrc = s->side[0] + s->block_samples;
222 sdst = s->side[1] + s->block_samples;
223 filter_samples(sdst, ssrc, s->block_samples,
224 b0, b1, b2, a1, a2,
225 &w1, &w2);
226
227 reverse_samples(s->side[2], s->side[1], s->block_samples * 2);
228 w1 = w2 = 0.;
229 filter_samples(s->side[2], s->side[2], s->block_samples * 2,
230 b0, b1, b2, a1, a2,
231 &w1, &w2);
232
233 reverse_samples(s->side[1], s->side[2], s->block_samples * 2);
234
235 src = (const double *)in->data[0];
236 ssrc = s->side[1];
237 for (int n = 0; n < out->nb_samples; n++, src += 2, dst += 2) {
238 if (ctx->is_disabled) {
239 dst[0] = src[0];
240 dst[1] = src[1];
241 } else {
242 dst[0] = (msrc[n] + ssrc[n]) * level_out;
243 dst[1] = (msrc[n] - ssrc[n]) * level_out;
244 }
245 }
246
247 memmove(s->mid, s->mid + s->block_samples,
248 s->block_samples * sizeof(*s->mid));
249 memmove(s->side[0], s->side[0] + s->block_samples,
250 s->block_samples * sizeof(*s->side[0]));
251 }
252
253 if (s->block_samples > 0) {
254 int nb_samples = in->nb_samples;
255 int64_t pts = in->pts;
256
257 out->pts = s->pts;
258 out->nb_samples = s->nb_samples;
259 s->pts = pts;
260 s->nb_samples = nb_samples;
261 }
262
263 if (out != in)
264 av_frame_free(&in);
265 if (!drop) {
266 return ff_filter_frame(outlink, out);
267 } else {
268 av_frame_free(&out);
269 ff_filter_set_ready(ctx, 10);
270 return 0;
271 }
272 }
273
activate(AVFilterContext * ctx)274 static int activate(AVFilterContext *ctx)
275 {
276 AVFilterLink *inlink = ctx->inputs[0];
277 AVFilterLink *outlink = ctx->outputs[0];
278 CrossfeedContext *s = ctx->priv;
279 AVFrame *in = NULL;
280 int64_t pts;
281 int status;
282 int ret;
283
284 FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink);
285
286 if (s->block_samples > 0) {
287 ret = ff_inlink_consume_samples(inlink, s->block_samples, s->block_samples, &in);
288 } else {
289 ret = ff_inlink_consume_frame(inlink, &in);
290 }
291 if (ret < 0)
292 return ret;
293 if (ret > 0)
294 return filter_frame(inlink, in, 0);
295
296 if (s->block_samples > 0 && ff_inlink_queued_samples(inlink) >= s->block_samples) {
297 ff_filter_set_ready(ctx, 10);
298 return 0;
299 }
300
301 if (ff_inlink_acknowledge_status(inlink, &status, &pts)) {
302 if (s->block_samples > 0) {
303 AVFrame *in = ff_get_audio_buffer(outlink, s->block_samples);
304 if (!in)
305 return AVERROR(ENOMEM);
306
307 ret = filter_frame(inlink, in, 1);
308 }
309
310 ff_outlink_set_status(outlink, status, pts);
311
312 return ret;
313 }
314
315 FF_FILTER_FORWARD_WANTED(outlink, inlink);
316
317 return FFERROR_NOT_READY;
318 }
319
process_command(AVFilterContext * ctx,const char * cmd,const char * args,char * res,int res_len,int flags)320 static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
321 char *res, int res_len, int flags)
322 {
323 int ret;
324
325 ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
326 if (ret < 0)
327 return ret;
328
329 return config_input(ctx->inputs[0]);
330 }
331
uninit(AVFilterContext * ctx)332 static av_cold void uninit(AVFilterContext *ctx)
333 {
334 CrossfeedContext *s = ctx->priv;
335
336 av_freep(&s->mid);
337 for (int i = 0; i < 3; i++)
338 av_freep(&s->side[i]);
339 }
340
341 #define OFFSET(x) offsetof(CrossfeedContext, x)
342 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
343 #define AF AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
344
345 static const AVOption crossfeed_options[] = {
346 { "strength", "set crossfeed strength", OFFSET(strength), AV_OPT_TYPE_DOUBLE, {.dbl=.2}, 0, 1, FLAGS },
347 { "range", "set soundstage wideness", OFFSET(range), AV_OPT_TYPE_DOUBLE, {.dbl=.5}, 0, 1, FLAGS },
348 { "slope", "set curve slope", OFFSET(slope), AV_OPT_TYPE_DOUBLE, {.dbl=.5}, .01, 1, FLAGS },
349 { "level_in", "set level in", OFFSET(level_in), AV_OPT_TYPE_DOUBLE, {.dbl=.9}, 0, 1, FLAGS },
350 { "level_out", "set level out", OFFSET(level_out), AV_OPT_TYPE_DOUBLE, {.dbl=1.}, 0, 1, FLAGS },
351 { "block_size", "set the block size", OFFSET(block_size),AV_OPT_TYPE_INT, {.i64=0}, 0, 32768, AF },
352 { NULL }
353 };
354
355 AVFILTER_DEFINE_CLASS(crossfeed);
356
357 static const AVFilterPad inputs[] = {
358 {
359 .name = "default",
360 .type = AVMEDIA_TYPE_AUDIO,
361 .config_props = config_input,
362 },
363 };
364
365 static const AVFilterPad outputs[] = {
366 {
367 .name = "default",
368 .type = AVMEDIA_TYPE_AUDIO,
369 },
370 };
371
372 const AVFilter ff_af_crossfeed = {
373 .name = "crossfeed",
374 .description = NULL_IF_CONFIG_SMALL("Apply headphone crossfeed filter."),
375 .priv_size = sizeof(CrossfeedContext),
376 .priv_class = &crossfeed_class,
377 .activate = activate,
378 .uninit = uninit,
379 FILTER_INPUTS(inputs),
380 FILTER_OUTPUTS(outputs),
381 FILTER_QUERY_FUNC(query_formats),
382 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL,
383 .process_command = process_command,
384 };
385