FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavfilter/af_pan.c
Date: 2024-07-24 19:24:46
Exec Total Coverage
Lines: 162 217 74.7%
Functions: 8 8 100.0%
Branches: 94 128 73.4%

Line Branch Exec Source
1 /*
2 * Copyright (c) 2002 Anders Johansson <ajh@atri.curtin.edu.au>
3 * Copyright (c) 2011 Clément Bœsch <u pkh me>
4 * Copyright (c) 2011 Nicolas George <nicolas.george@normalesup.org>
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /**
24 * @file
25 * Audio panning filter (channels mixing)
26 * Original code written by Anders Johansson for MPlayer,
27 * reimplemented for FFmpeg.
28 */
29
30 #include <stdio.h>
31 #include "libavutil/avstring.h"
32 #include "libavutil/channel_layout.h"
33 #include "libavutil/mem.h"
34 #include "libavutil/opt.h"
35 #include "libswresample/swresample.h"
36 #include "audio.h"
37 #include "avfilter.h"
38 #include "formats.h"
39 #include "internal.h"
40
41 #define MAX_CHANNELS 64
42
43 typedef struct PanContext {
44 const AVClass *class;
45 char *args;
46 AVChannelLayout out_channel_layout;
47 double gain[MAX_CHANNELS][MAX_CHANNELS];
48 int64_t need_renorm;
49 int need_renumber;
50 int nb_output_channels;
51
52 int pure_gains;
53 /* channel mapping specific */
54 int channel_map[MAX_CHANNELS];
55 struct SwrContext *swr;
56 } PanContext;
57
58 588 static void skip_spaces(char **arg)
59 {
60 588 int len = 0;
61
62 588 sscanf(*arg, " %n", &len);
63 588 *arg += len;
64 588 }
65
66 294 static int parse_channel_name(char **arg, int *rchannel, int *rnamed)
67 {
68 char buf[8];
69 294 int len, channel_id = 0;
70
71 294 skip_spaces(arg);
72 /* try to parse a channel name, e.g. "FL" */
73
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294 if (sscanf(*arg, "%7[A-Z]%n", buf, &len)) {
74 36 channel_id = av_channel_from_string(buf);
75
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36 if (channel_id < 0)
76 return channel_id;
77
78 36 *rchannel = channel_id;
79 36 *rnamed = 1;
80 36 *arg += len;
81 36 return 0;
82 }
83 /* try to parse a channel number, e.g. "c2" */
84
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258 if (sscanf(*arg, "c%d%n", &channel_id, &len) &&
85
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258 channel_id >= 0 && channel_id < MAX_CHANNELS) {
86 258 *rchannel = channel_id;
87 258 *rnamed = 0;
88 258 *arg += len;
89 258 return 0;
90 }
91 return AVERROR(EINVAL);
92 }
93
94 48 static av_cold int init(AVFilterContext *ctx)
95 {
96 48 PanContext *const pan = ctx->priv;
97 48 char *arg, *arg0, *tokenizer, *args = av_strdup(pan->args);
98 48 int out_ch_id, in_ch_id, len, named, ret, sign = 1;
99 48 int nb_in_channels[2] = { 0, 0 }; // number of unnamed and named input channels
100 48 int used_out_ch[MAX_CHANNELS] = {0};
101 double gain;
102
103
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48 if (!pan->args) {
104 av_log(ctx, AV_LOG_ERROR,
105 "pan filter needs a channel layout and a set "
106 "of channel definitions as parameter\n");
107 return AVERROR(EINVAL);
108 }
109
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48 if (!args)
110 return AVERROR(ENOMEM);
111 48 arg = av_strtok(args, "|", &tokenizer);
112
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48 if (!arg) {
113 av_log(ctx, AV_LOG_ERROR, "Channel layout not specified\n");
114 ret = AVERROR(EINVAL);
115 goto fail;
116 }
117 48 ret = ff_parse_channel_layout(&pan->out_channel_layout,
118 &pan->nb_output_channels, arg, ctx);
119
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48 if (ret < 0)
120 goto fail;
121
122
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48 if (pan->nb_output_channels > MAX_CHANNELS) {
123 av_log(ctx, AV_LOG_ERROR,
124 "af_pan supports a maximum of %d channels. "
125 "Feel free to ask for a higher limit.\n", MAX_CHANNELS);
126 ret = AVERROR_PATCHWELCOME;
127 goto fail;
128 }
129
130 /* parse channel specifications */
131
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170 while ((arg = arg0 = av_strtok(NULL, "|", &tokenizer))) {
132 122 int used_in_ch[MAX_CHANNELS] = {0};
133 /* channel name */
134
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122 if (parse_channel_name(&arg, &out_ch_id, &named)) {
135 av_log(ctx, AV_LOG_ERROR,
136 "Expected out channel name, got \"%.8s\"\n", arg);
137 ret = AVERROR(EINVAL);
138 goto fail;
139 }
140
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122 if (named) {
141
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14 if ((out_ch_id = av_channel_layout_index_from_channel(&pan->out_channel_layout, out_ch_id)) < 0) {
142 av_log(ctx, AV_LOG_ERROR,
143 "Channel \"%.8s\" does not exist in the chosen layout\n", arg0);
144 ret = AVERROR(EINVAL);
145 goto fail;
146 }
147 }
148
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122 if (out_ch_id < 0 || out_ch_id >= pan->nb_output_channels) {
149 av_log(ctx, AV_LOG_ERROR,
150 "Invalid out channel name \"%.8s\"\n", arg0);
151 ret = AVERROR(EINVAL);
152 goto fail;
153 }
154
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122 if (used_out_ch[out_ch_id]) {
155 av_log(ctx, AV_LOG_ERROR,
156 "Can not reference out channel %d twice\n", out_ch_id);
157 ret = AVERROR(EINVAL);
158 goto fail;
159 }
160 122 used_out_ch[out_ch_id] = 1;
161 122 skip_spaces(&arg);
162
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122 if (*arg == '=') {
163 114 arg++;
164
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8 } else if (*arg == '<') {
165 8 pan->need_renorm |= (int64_t)1 << out_ch_id;
166 8 arg++;
167 } else {
168 av_log(ctx, AV_LOG_ERROR,
169 "Syntax error after channel name in \"%.8s\"\n", arg0);
170 ret = AVERROR(EINVAL);
171 goto fail;
172 }
173 /* gains */
174 122 sign = 1;
175 while (1) {
176 172 gain = 1;
177
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172 if (sscanf(arg, "%lf%n *%n", &gain, &len, &len))
178 36 arg += len;
179
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172 if (parse_channel_name(&arg, &in_ch_id, &named)){
180 av_log(ctx, AV_LOG_ERROR,
181 "Expected in channel name, got \"%.8s\"\n", arg);
182 ret = AVERROR(EINVAL);
183 goto fail;
184 }
185 172 nb_in_channels[named]++;
186
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172 if (nb_in_channels[!named]) {
187 av_log(ctx, AV_LOG_ERROR,
188 "Can not mix named and numbered channels\n");
189 ret = AVERROR(EINVAL);
190 goto fail;
191 }
192
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172 if (used_in_ch[in_ch_id]) {
193 av_log(ctx, AV_LOG_ERROR,
194 "Can not reference in channel %d twice\n", in_ch_id);
195 ret = AVERROR(EINVAL);
196 goto fail;
197 }
198 172 used_in_ch[in_ch_id] = 1;
199 172 pan->gain[out_ch_id][in_ch_id] = sign * gain;
200 172 skip_spaces(&arg);
201
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172 if (!*arg)
202 122 break;
203
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50 if (*arg == '-') {
204 18 sign = -1;
205
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32 } else if (*arg != '+') {
206 av_log(ctx, AV_LOG_ERROR, "Syntax error near \"%.8s\"\n", arg);
207 ret = AVERROR(EINVAL);
208 goto fail;
209 } else {
210 32 sign = 1;
211 }
212 50 arg++;
213 }
214 }
215 48 pan->need_renumber = !!nb_in_channels[1];
216
217 48 ret = 0;
218 48 fail:
219 48 av_free(args);
220 48 return ret;
221 }
222
223 24 static int are_gains_pure(const PanContext *pan)
224 {
225 int i, j;
226
227
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1048 for (i = 0; i < MAX_CHANNELS; i++) {
228 1032 int nb_gain = 0;
229
230
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66576 for (j = 0; j < MAX_CHANNELS; j++) {
231 65552 double gain = pan->gain[i][j];
232
233 /* channel mapping is effective only if 0% or 100% of a channel is
234 * selected... */
235
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65552 if (gain != 0. && gain != 1.)
236 7 return 0;
237 /* ...and if the output channel is only composed of one input */
238
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65545 if (gain && nb_gain++)
239 1 return 0;
240 }
241 }
242 16 return 1;
243 }
244
245 24 static int query_formats(AVFilterContext *ctx)
246 {
247 24 PanContext *pan = ctx->priv;
248 24 AVFilterLink *inlink = ctx->inputs[0];
249 24 AVFilterLink *outlink = ctx->outputs[0];
250 AVFilterChannelLayouts *layouts;
251 int ret;
252
253 24 pan->pure_gains = are_gains_pure(pan);
254 /* libswr supports any sample and packing formats */
255
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24 if ((ret = ff_set_common_formats(ctx, ff_all_formats(AVMEDIA_TYPE_AUDIO))) < 0)
256 return ret;
257
258
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24 if ((ret = ff_set_common_all_samplerates(ctx)) < 0)
259 return ret;
260
261 // inlink supports any channel layout
262 24 layouts = ff_all_channel_counts();
263
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24 if ((ret = ff_channel_layouts_ref(layouts, &inlink->outcfg.channel_layouts)) < 0)
264 return ret;
265
266 // outlink supports only requested output channel layout
267 24 layouts = NULL;
268
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24 if ((ret = ff_add_channel_layout(&layouts, &pan->out_channel_layout)) < 0)
269 return ret;
270 24 return ff_channel_layouts_ref(layouts, &outlink->incfg.channel_layouts);
271 }
272
273 24 static int config_props(AVFilterLink *link)
274 {
275 24 AVFilterContext *ctx = link->dst;
276 24 PanContext *pan = ctx->priv;
277 char buf[1024], *cur;
278 int i, j, k, r, ret;
279 double t;
280
281
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24 if (pan->need_renumber) {
282 // input channels were given by their name: renumber them
283
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195 for (i = j = 0; i < MAX_CHANNELS; i++) {
284
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192 if (av_channel_layout_index_from_channel(&link->ch_layout, i) >= 0) {
285
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25 for (k = 0; k < pan->nb_output_channels; k++)
286 16 pan->gain[k][j] = pan->gain[k][i];
287 9 j++;
288 }
289 }
290 }
291
292 // sanity check; can't be done in query_formats since the inlink
293 // channel layout is unknown at that time
294
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24 if (link->ch_layout.nb_channels > MAX_CHANNELS ||
295
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24 pan->nb_output_channels > MAX_CHANNELS) {
296 av_log(ctx, AV_LOG_ERROR,
297 "af_pan supports a maximum of %d channels. "
298 "Feel free to ask for a higher limit.\n", MAX_CHANNELS);
299 return AVERROR_PATCHWELCOME;
300 }
301
302 // init libswresample context
303 24 ret = swr_alloc_set_opts2(&pan->swr,
304 24 &pan->out_channel_layout, link->format, link->sample_rate,
305 24 &link->ch_layout, link->format, link->sample_rate,
306 0, ctx);
307
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24 if (ret < 0)
308 return AVERROR(ENOMEM);
309
310 // gains are pure, init the channel mapping
311
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24 if (pan->pure_gains) {
312
313 // get channel map from the pure gains
314
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50 for (i = 0; i < pan->nb_output_channels; i++) {
315 34 int ch_id = -1;
316
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42 for (j = 0; j < link->ch_layout.nb_channels; j++) {
317
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35 if (pan->gain[i][j]) {
318 27 ch_id = j;
319 27 break;
320 }
321 }
322 34 pan->channel_map[i] = ch_id;
323 }
324
325 16 av_opt_set_chlayout(pan->swr, "uchl", &pan->out_channel_layout, 0);
326 16 swr_set_channel_mapping(pan->swr, pan->channel_map);
327 } else {
328 // renormalize
329
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35 for (i = 0; i < pan->nb_output_channels; i++) {
330
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27 if (!((pan->need_renorm >> i) & 1))
331 23 continue;
332 4 t = 0;
333
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16 for (j = 0; j < link->ch_layout.nb_channels; j++)
334 12 t += fabs(pan->gain[i][j]);
335
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4 if (t > -1E-5 && t < 1E-5) {
336 // t is almost 0 but not exactly, this is probably a mistake
337 if (t)
338 av_log(ctx, AV_LOG_WARNING,
339 "Degenerate coefficients while renormalizing\n");
340 continue;
341 }
342
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16 for (j = 0; j < link->ch_layout.nb_channels; j++)
343 12 pan->gain[i][j] /= t;
344 }
345 8 swr_set_matrix(pan->swr, pan->gain[0], pan->gain[1] - pan->gain[0]);
346 }
347
348 24 r = swr_init(pan->swr);
349
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24 if (r < 0)
350 return r;
351
352 // summary
353
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85 for (i = 0; i < pan->nb_output_channels; i++) {
354 61 cur = buf;
355
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223 for (j = 0; j < link->ch_layout.nb_channels; j++) {
356
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162 r = snprintf(cur, buf + sizeof(buf) - cur, "%s%.3g i%d",
357 j ? " + " : "", pan->gain[i][j], j);
358
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162 cur += FFMIN(buf + sizeof(buf) - cur, r);
359 }
360 61 av_log(ctx, AV_LOG_VERBOSE, "o%d = %s\n", i, buf);
361 }
362 // add channel mapping summary if possible
363
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24 if (pan->pure_gains) {
364 16 av_log(ctx, AV_LOG_INFO, "Pure channel mapping detected:");
365
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50 for (i = 0; i < pan->nb_output_channels; i++)
366
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34 if (pan->channel_map[i] < 0)
367 7 av_log(ctx, AV_LOG_INFO, " M");
368 else
369 27 av_log(ctx, AV_LOG_INFO, " %d", pan->channel_map[i]);
370 16 av_log(ctx, AV_LOG_INFO, "\n");
371 16 return 0;
372 }
373 8 return 0;
374 }
375
376 1110 static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
377 {
378 int ret;
379 1110 int n = insamples->nb_samples;
380 1110 AVFilterLink *const outlink = inlink->dst->outputs[0];
381 1110 AVFrame *outsamples = ff_get_audio_buffer(outlink, n);
382 1110 PanContext *pan = inlink->dst->priv;
383
384
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1110 if (!outsamples) {
385 av_frame_free(&insamples);
386 return AVERROR(ENOMEM);
387 }
388 1110 swr_convert(pan->swr, outsamples->extended_data, n,
389 1110 (void *)insamples->extended_data, n);
390 1110 av_frame_copy_props(outsamples, insamples);
391
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1110 if ((ret = av_channel_layout_copy(&outsamples->ch_layout, &outlink->ch_layout)) < 0) {
392 av_frame_free(&outsamples);
393 av_frame_free(&insamples);
394 return ret;
395 }
396
397 1110 av_frame_free(&insamples);
398 1110 return ff_filter_frame(outlink, outsamples);
399 }
400
401 48 static av_cold void uninit(AVFilterContext *ctx)
402 {
403 48 PanContext *pan = ctx->priv;
404 48 swr_free(&pan->swr);
405 48 av_channel_layout_uninit(&pan->out_channel_layout);
406 48 }
407
408 #define OFFSET(x) offsetof(PanContext, x)
409
410 static const AVOption pan_options[] = {
411 { "args", NULL, OFFSET(args), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM },
412 { NULL }
413 };
414
415 AVFILTER_DEFINE_CLASS(pan);
416
417 static const AVFilterPad pan_inputs[] = {
418 {
419 .name = "default",
420 .type = AVMEDIA_TYPE_AUDIO,
421 .config_props = config_props,
422 .filter_frame = filter_frame,
423 },
424 };
425
426 const AVFilter ff_af_pan = {
427 .name = "pan",
428 .description = NULL_IF_CONFIG_SMALL("Remix channels with coefficients (panning)."),
429 .priv_size = sizeof(PanContext),
430 .priv_class = &pan_class,
431 .init = init,
432 .uninit = uninit,
433 FILTER_INPUTS(pan_inputs),
434 FILTER_OUTPUTS(ff_audio_default_filterpad),
435 FILTER_QUERY_FUNC(query_formats),
436 };
437