path: root/libavfilter/af_compand.c (plain)
blob: 0bb719fae5a38cefda20d5e027bda90a40319408

1	/*
2	* Copyright (c) 1999 Chris Bagwell
3	* Copyright (c) 1999 Nick Bailey
4	* Copyright (c) 2007 Rob Sykes <robs@users.sourceforge.net>
5	* Copyright (c) 2013 Paul B Mahol
6	* Copyright (c) 2014 Andrew Kelley
7	*
8	* This file is part of FFmpeg.
9	*
10	* FFmpeg is free software; you can redistribute it and/or
11	* modify it under the terms of the GNU Lesser General Public
12	* License as published by the Free Software Foundation; either
13	* version 2.1 of the License, or (at your option) any later version.
14	*
15	* FFmpeg is distributed in the hope that it will be useful,
16	* but WITHOUT ANY WARRANTY; without even the implied warranty of
17	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18	* Lesser General Public License for more details.
19	*
20	* You should have received a copy of the GNU Lesser General Public
21	* License along with FFmpeg; if not, write to the Free Software
22	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23	*/
24
25	/**
26	* @file
27	* audio compand filter
28	*/
29
30	#include "libavutil/avassert.h"
31	#include "libavutil/avstring.h"
32	#include "libavutil/ffmath.h"
33	#include "libavutil/opt.h"
34	#include "libavutil/samplefmt.h"
35	#include "audio.h"
36	#include "avfilter.h"
37	#include "internal.h"
38
39	typedef struct ChanParam {
40	double attack;
41	double decay;
42	double volume;
43	} ChanParam;
44
45	typedef struct CompandSegment {
46	double x, y;
47	double a, b;
48	} CompandSegment;
49
50	typedef struct CompandContext {
51	const AVClass *class;
52	int nb_segments;
53	char *attacks, *decays, *points;
54	CompandSegment *segments;
55	ChanParam *channels;
56	double in_min_lin;
57	double out_min_lin;
58	double curve_dB;
59	double gain_dB;
60	double initial_volume;
61	double delay;
62	AVFrame *delay_frame;
63	int delay_samples;
64	int delay_count;
65	int delay_index;
66	int64_t pts;
67
68	int (*compand)(AVFilterContext *ctx, AVFrame *frame);
69	} CompandContext;
70
71	#define OFFSET(x) offsetof(CompandContext, x)
72	#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
73
74	static const AVOption compand_options[] = {
75	{ "attacks", "set time over which increase of volume is determined", OFFSET(attacks), AV_OPT_TYPE_STRING, { .str = "0.3" }, 0, 0, A },
76	{ "decays", "set time over which decrease of volume is determined", OFFSET(decays), AV_OPT_TYPE_STRING, { .str = "0.8" }, 0, 0, A },
77	{ "points", "set points of transfer function", OFFSET(points), AV_OPT_TYPE_STRING, { .str = "-70/-70|-60/-20" }, 0, 0, A },
78	{ "soft-knee", "set soft-knee", OFFSET(curve_dB), AV_OPT_TYPE_DOUBLE, { .dbl = 0.01 }, 0.01, 900, A },
79	{ "gain", "set output gain", OFFSET(gain_dB), AV_OPT_TYPE_DOUBLE, { .dbl = 0 }, -900, 900, A },
80	{ "volume", "set initial volume", OFFSET(initial_volume), AV_OPT_TYPE_DOUBLE, { .dbl = 0 }, -900, 0, A },
81	{ "delay", "set delay for samples before sending them to volume adjuster", OFFSET(delay), AV_OPT_TYPE_DOUBLE, { .dbl = 0 }, 0, 20, A },
82	{ NULL }
83	};
84
85	AVFILTER_DEFINE_CLASS(compand);
86
87	static av_cold int init(AVFilterContext *ctx)
88	{
89	CompandContext *s = ctx->priv;
90	s->pts = AV_NOPTS_VALUE;
91	return 0;
92	}
93
94	static av_cold void uninit(AVFilterContext *ctx)
95	{
96	CompandContext *s = ctx->priv;
97
98	av_freep(&s->channels);
99	av_freep(&s->segments);
100	av_frame_free(&s->delay_frame);
101	}
102
103	static int query_formats(AVFilterContext *ctx)
104	{
105	AVFilterChannelLayouts *layouts;
106	AVFilterFormats *formats;
107	static const enum AVSampleFormat sample_fmts[] = {
108	AV_SAMPLE_FMT_DBLP,
109	AV_SAMPLE_FMT_NONE
110	};
111	int ret;
112
113	layouts = ff_all_channel_counts();
114	if (!layouts)
115	return AVERROR(ENOMEM);
116	ret = ff_set_common_channel_layouts(ctx, layouts);
117	if (ret < 0)
118	return ret;
119
120	formats = ff_make_format_list(sample_fmts);
121	if (!formats)
122	return AVERROR(ENOMEM);
123	ret = ff_set_common_formats(ctx, formats);
124	if (ret < 0)
125	return ret;
126
127	formats = ff_all_samplerates();
128	if (!formats)
129	return AVERROR(ENOMEM);
130	return ff_set_common_samplerates(ctx, formats);
131	}
132
133	static void count_items(char *item_str, int *nb_items)
134	{
135	char *p;
136
137	*nb_items = 1;
138	for (p = item_str; *p; p++) {
139	if (*p == ' ' || *p == '|')
140	(*nb_items)++;
141	}
142	}
143
144	static void update_volume(ChanParam *cp, double in)
145	{
146	double delta = in - cp->volume;
147
148	if (delta > 0.0)
149	cp->volume += delta * cp->attack;
150	else
151	cp->volume += delta * cp->decay;
152	}
153
154	static double get_volume(CompandContext *s, double in_lin)
155	{
156	CompandSegment *cs;
157	double in_log, out_log;
158	int i;
159
160	if (in_lin < s->in_min_lin)
161	return s->out_min_lin;
162
163	in_log = log(in_lin);
164
165	for (i = 1; i < s->nb_segments; i++)
166	if (in_log <= s->segments[i].x)
167	break;
168	cs = &s->segments[i - 1];
169	in_log -= cs->x;
170	out_log = cs->y + in_log * (cs->a * in_log + cs->b);
171
172	return exp(out_log);
173	}
174
175	static int compand_nodelay(AVFilterContext *ctx, AVFrame *frame)
176	{
177	CompandContext *s = ctx->priv;
178	AVFilterLink *inlink = ctx->inputs[0];
179	const int channels = inlink->channels;
180	const int nb_samples = frame->nb_samples;
181	AVFrame *out_frame;
182	int chan, i;
183	int err;
184
185	if (av_frame_is_writable(frame)) {
186	out_frame = frame;
187	} else {
188	out_frame = ff_get_audio_buffer(inlink, nb_samples);
189	if (!out_frame) {
190	av_frame_free(&frame);
191	return AVERROR(ENOMEM);
192	}
193	err = av_frame_copy_props(out_frame, frame);
194	if (err < 0) {
195	av_frame_free(&out_frame);
196	av_frame_free(&frame);
197	return err;
198	}
199	}
200
201	for (chan = 0; chan < channels; chan++) {
202	const double *src = (double *)frame->extended_data[chan];
203	double *dst = (double *)out_frame->extended_data[chan];
204	ChanParam *cp = &s->channels[chan];
205
206	for (i = 0; i < nb_samples; i++) {
207	update_volume(cp, fabs(src[i]));
208
209	dst[i] = src[i] * get_volume(s, cp->volume);
210	}
211	}
212
213	if (frame != out_frame)
214	av_frame_free(&frame);
215
216	return ff_filter_frame(ctx->outputs[0], out_frame);
217	}
218
219	#define MOD(a, b) (((a) >= (b)) ? (a) - (b) : (a))
220
221	static int compand_delay(AVFilterContext *ctx, AVFrame *frame)
222	{
223	CompandContext *s = ctx->priv;
224	AVFilterLink *inlink = ctx->inputs[0];
225	const int channels = inlink->channels;
226	const int nb_samples = frame->nb_samples;
227	int chan, i, av_uninit(dindex), oindex, av_uninit(count);
228	AVFrame *out_frame = NULL;
229	int err;
230
231	if (s->pts == AV_NOPTS_VALUE) {
232	s->pts = (frame->pts == AV_NOPTS_VALUE) ? 0 : frame->pts;
233	}
234
235	av_assert1(channels > 0); /* would corrupt delay_count and delay_index */
236
237	for (chan = 0; chan < channels; chan++) {
238	AVFrame *delay_frame = s->delay_frame;
239	const double *src = (double *)frame->extended_data[chan];
240	double *dbuf = (double *)delay_frame->extended_data[chan];
241	ChanParam *cp = &s->channels[chan];
242	double *dst;
243
244	count = s->delay_count;
245	dindex = s->delay_index;
246	for (i = 0, oindex = 0; i < nb_samples; i++) {
247	const double in = src[i];
248	update_volume(cp, fabs(in));
249
250	if (count >= s->delay_samples) {
251	if (!out_frame) {
252	out_frame = ff_get_audio_buffer(inlink, nb_samples - i);
253	if (!out_frame) {
254	av_frame_free(&frame);
255	return AVERROR(ENOMEM);
256	}
257	err = av_frame_copy_props(out_frame, frame);
258	if (err < 0) {
259	av_frame_free(&out_frame);
260	av_frame_free(&frame);
261	return err;
262	}
263	out_frame->pts = s->pts;
264	s->pts += av_rescale_q(nb_samples - i,
265	(AVRational){ 1, inlink->sample_rate },
266	inlink->time_base);
267	}
268
269	dst = (double *)out_frame->extended_data[chan];
270	dst[oindex++] = dbuf[dindex] * get_volume(s, cp->volume);
271	} else {
272	count++;
273	}
274
275	dbuf[dindex] = in;
276	dindex = MOD(dindex + 1, s->delay_samples);
277	}
278	}
279
280	s->delay_count = count;
281	s->delay_index = dindex;
282
283	av_frame_free(&frame);
284
285	if (out_frame) {
286	err = ff_filter_frame(ctx->outputs[0], out_frame);
287	return err;
288	}
289
290	return 0;
291	}
292
293	static int compand_drain(AVFilterLink *outlink)
294	{
295	AVFilterContext *ctx = outlink->src;
296	CompandContext *s = ctx->priv;
297	const int channels = outlink->channels;
298	AVFrame *frame = NULL;
299	int chan, i, dindex;
300
301	/* 2048 is to limit output frame size during drain */
302	frame = ff_get_audio_buffer(outlink, FFMIN(2048, s->delay_count));
303	if (!frame)
304	return AVERROR(ENOMEM);
305	frame->pts = s->pts;
306	s->pts += av_rescale_q(frame->nb_samples,
307	(AVRational){ 1, outlink->sample_rate }, outlink->time_base);
308
309	av_assert0(channels > 0);
310	for (chan = 0; chan < channels; chan++) {
311	AVFrame *delay_frame = s->delay_frame;
312	double *dbuf = (double *)delay_frame->extended_data[chan];
313	double *dst = (double *)frame->extended_data[chan];
314	ChanParam *cp = &s->channels[chan];
315
316	dindex = s->delay_index;
317	for (i = 0; i < frame->nb_samples; i++) {
318	dst[i] = dbuf[dindex] * get_volume(s, cp->volume);
319	dindex = MOD(dindex + 1, s->delay_samples);
320	}
321	}
322	s->delay_count -= frame->nb_samples;
323	s->delay_index = dindex;
324
325	return ff_filter_frame(outlink, frame);
326	}
327
328	static int config_output(AVFilterLink *outlink)
329	{
330	AVFilterContext *ctx = outlink->src;
331	CompandContext *s = ctx->priv;
332	const int sample_rate = outlink->sample_rate;
333	double radius = s->curve_dB * M_LN10 / 20.0;
334	char *p, *saveptr = NULL;
335	const int channels = outlink->channels;
336	int nb_attacks, nb_decays, nb_points;
337	int new_nb_items, num;
338	int i;
339	int err;
340
341
342	count_items(s->attacks, &nb_attacks);
343	count_items(s->decays, &nb_decays);
344	count_items(s->points, &nb_points);
345
346	if (channels <= 0) {
347	av_log(ctx, AV_LOG_ERROR, "Invalid number of channels: %d\n", channels);
348	return AVERROR(EINVAL);
349	}
350
351	if (nb_attacks > channels || nb_decays > channels) {
352	av_log(ctx, AV_LOG_ERROR,
353	"Number of attacks/decays bigger than number of channels.\n");
354	return AVERROR(EINVAL);
355	}
356
357	uninit(ctx);
358
359	s->channels = av_mallocz_array(channels, sizeof(*s->channels));
360	s->nb_segments = (nb_points + 4) * 2;
361	s->segments = av_mallocz_array(s->nb_segments, sizeof(*s->segments));
362
363	if (!s->channels || !s->segments) {
364	uninit(ctx);
365	return AVERROR(ENOMEM);
366	}
367
368	p = s->attacks;
369	for (i = 0, new_nb_items = 0; i < nb_attacks; i++) {
370	char *tstr = av_strtok(p, " |", &saveptr);
371	p = NULL;
372	new_nb_items += sscanf(tstr, "%lf", &s->channels[i].attack) == 1;
373	if (s->channels[i].attack < 0) {
374	uninit(ctx);
375	return AVERROR(EINVAL);
376	}
377	}
378	nb_attacks = new_nb_items;
379
380	p = s->decays;
381	for (i = 0, new_nb_items = 0; i < nb_decays; i++) {
382	char *tstr = av_strtok(p, " |", &saveptr);
383	p = NULL;
384	new_nb_items += sscanf(tstr, "%lf", &s->channels[i].decay) == 1;
385	if (s->channels[i].decay < 0) {
386	uninit(ctx);
387	return AVERROR(EINVAL);
388	}
389	}
390	nb_decays = new_nb_items;
391
392	if (nb_attacks != nb_decays) {
393	av_log(ctx, AV_LOG_ERROR,
394	"Number of attacks %d differs from number of decays %d.\n",
395	nb_attacks, nb_decays);
396	uninit(ctx);
397	return AVERROR(EINVAL);
398	}
399
400	for (i = nb_decays; i < channels; i++) {
401	s->channels[i].attack = s->channels[nb_decays - 1].attack;
402	s->channels[i].decay = s->channels[nb_decays - 1].decay;
403	}
404
405	#define S(x) s->segments[2 * ((x) + 1)]
406	p = s->points;
407	for (i = 0, new_nb_items = 0; i < nb_points; i++) {
408	char *tstr = av_strtok(p, " |", &saveptr);
409	p = NULL;
410	if (sscanf(tstr, "%lf/%lf", &S(i).x, &S(i).y) != 2) {
411	av_log(ctx, AV_LOG_ERROR,
412	"Invalid and/or missing input/output value.\n");
413	uninit(ctx);
414	return AVERROR(EINVAL);
415	}
416	if (i && S(i - 1).x > S(i).x) {
417	av_log(ctx, AV_LOG_ERROR,
418	"Transfer function input values must be increasing.\n");
419	uninit(ctx);
420	return AVERROR(EINVAL);
421	}
422	S(i).y -= S(i).x;
423	av_log(ctx, AV_LOG_DEBUG, "%d: x=%f y=%f\n", i, S(i).x, S(i).y);
424	new_nb_items++;
425	}
426	num = new_nb_items;
427
428	/* Add 0,0 if necessary */
429	if (num == 0 || S(num - 1).x)
430	num++;
431
432	#undef S
433	#define S(x) s->segments[2 * (x)]
434	/* Add a tail off segment at the start */
435	S(0).x = S(1).x - 2 * s->curve_dB;
436	S(0).y = S(1).y;
437	num++;
438
439	/* Join adjacent colinear segments */
440	for (i = 2; i < num; i++) {
441	double g1 = (S(i - 1).y - S(i - 2).y) * (S(i - 0).x - S(i - 1).x);
442	double g2 = (S(i - 0).y - S(i - 1).y) * (S(i - 1).x - S(i - 2).x);
443	int j;
444
445	if (fabs(g1 - g2))
446	continue;
447	num--;
448	for (j = --i; j < num; j++)
449	S(j) = S(j + 1);
450	}
451
452	for (i = 0; i < s->nb_segments; i += 2) {
453	s->segments[i].y += s->gain_dB;
454	s->segments[i].x *= M_LN10 / 20;
455	s->segments[i].y *= M_LN10 / 20;
456	}
457
458	#define L(x) s->segments[i - (x)]
459	for (i = 4; i < s->nb_segments; i += 2) {
460	double x, y, cx, cy, in1, in2, out1, out2, theta, len, r;
461
462	L(4).a = 0;
463	L(4).b = (L(2).y - L(4).y) / (L(2).x - L(4).x);
464
465	L(2).a = 0;
466	L(2).b = (L(0).y - L(2).y) / (L(0).x - L(2).x);
467
468	theta = atan2(L(2).y - L(4).y, L(2).x - L(4).x);
469	len = hypot(L(2).x - L(4).x, L(2).y - L(4).y);
470	r = FFMIN(radius, len);
471	L(3).x = L(2).x - r * cos(theta);
472	L(3).y = L(2).y - r * sin(theta);
473
474	theta = atan2(L(0).y - L(2).y, L(0).x - L(2).x);
475	len = hypot(L(0).x - L(2).x, L(0).y - L(2).y);
476	r = FFMIN(radius, len / 2);
477	x = L(2).x + r * cos(theta);
478	y = L(2).y + r * sin(theta);
479
480	cx = (L(3).x + L(2).x + x) / 3;
481	cy = (L(3).y + L(2).y + y) / 3;
482
483	L(2).x = x;
484	L(2).y = y;
485
486	in1 = cx - L(3).x;
487	out1 = cy - L(3).y;
488	in2 = L(2).x - L(3).x;
489	out2 = L(2).y - L(3).y;
490	L(3).a = (out2 / in2 - out1 / in1) / (in2 - in1);
491	L(3).b = out1 / in1 - L(3).a * in1;
492	}
493	L(3).x = 0;
494	L(3).y = L(2).y;
495
496	s->in_min_lin = exp(s->segments[1].x);
497	s->out_min_lin = exp(s->segments[1].y);
498
499	for (i = 0; i < channels; i++) {
500	ChanParam *cp = &s->channels[i];
501
502	if (cp->attack > 1.0 / sample_rate)
503	cp->attack = 1.0 - exp(-1.0 / (sample_rate * cp->attack));
504	else
505	cp->attack = 1.0;
506	if (cp->decay > 1.0 / sample_rate)
507	cp->decay = 1.0 - exp(-1.0 / (sample_rate * cp->decay));
508	else
509	cp->decay = 1.0;
510	cp->volume = ff_exp10(s->initial_volume / 20);
511	}
512
513	s->delay_samples = s->delay * sample_rate;
514	if (s->delay_samples <= 0) {
515	s->compand = compand_nodelay;
516	return 0;
517	}
518
519	s->delay_frame = av_frame_alloc();
520	if (!s->delay_frame) {
521	uninit(ctx);
522	return AVERROR(ENOMEM);
523	}
524
525	s->delay_frame->format = outlink->format;
526	s->delay_frame->nb_samples = s->delay_samples;
527	s->delay_frame->channel_layout = outlink->channel_layout;
528
529	err = av_frame_get_buffer(s->delay_frame, 32);
530	if (err)
531	return err;
532
533	s->compand = compand_delay;
534	return 0;
535	}
536
537	static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
538	{
539	AVFilterContext *ctx = inlink->dst;
540	CompandContext *s = ctx->priv;
541
542	return s->compand(ctx, frame);
543	}
544
545	static int request_frame(AVFilterLink *outlink)
546	{
547	AVFilterContext *ctx = outlink->src;
548	CompandContext *s = ctx->priv;
549	int ret = 0;
550
551	ret = ff_request_frame(ctx->inputs[0]);
552
553	if (ret == AVERROR_EOF && !ctx->is_disabled && s->delay_count)
554	ret = compand_drain(outlink);
555
556	return ret;
557	}
558
559	static const AVFilterPad compand_inputs[] = {
560	{
561	.name = "default",
562	.type = AVMEDIA_TYPE_AUDIO,
563	.filter_frame = filter_frame,
564	},
565	{ NULL }
566	};
567
568	static const AVFilterPad compand_outputs[] = {
569	{
570	.name = "default",
571	.request_frame = request_frame,
572	.config_props = config_output,
573	.type = AVMEDIA_TYPE_AUDIO,
574	},
575	{ NULL }
576	};
577
578
579	AVFilter ff_af_compand = {
580	.name = "compand",
581	.description = NULL_IF_CONFIG_SMALL(
582	"Compress or expand audio dynamic range."),
583	.query_formats = query_formats,
584	.priv_size = sizeof(CompandContext),
585	.priv_class = &compand_class,
586	.init = init,
587	.uninit = uninit,
588	.inputs = compand_inputs,
589	.outputs = compand_outputs,
590	};
591