FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavfilter/af_channelmap.c
Date: 2026-04-24 19:58:39
Exec Total Coverage
Lines: 152 237 64.1%
Functions: 9 9 100.0%
Branches: 77 143 53.8%
Line Branch Exec Source
1 /*
2 * Copyright (c) 2012 Google, Inc.
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 /**
22 * @file
23 * audio channel mapping filter
24 */
25
26 #include <ctype.h>
27
28 #include "libavutil/avstring.h"
29 #include "libavutil/channel_layout.h"
30 #include "libavutil/common.h"
31 #include "libavutil/mathematics.h"
32 #include "libavutil/mem.h"
33 #include "libavutil/opt.h"
34 #include "libavutil/samplefmt.h"
35
36 #include "audio.h"
37 #include "avfilter.h"
38 #include "filters.h"
39 #include "formats.h"
40
41 struct ChannelMap {
42 int in_channel;
43 int out_channel;
44 int in_channel_idx;
45 int out_channel_idx;
46 };
47
48 enum MappingMode {
49 MAP_NONE,
50 MAP_ONE_INT,
51 MAP_ONE_STR,
52 MAP_PAIR_INT_INT,
53 MAP_PAIR_INT_STR,
54 MAP_PAIR_STR_INT,
55 MAP_PAIR_STR_STR
56 };
57
58 typedef struct ChannelMapContext {
59 const AVClass *class;
60 char *mapping_str;
61 AVChannelLayout output_layout;
62 struct ChannelMap *map;
63 int nch;
64 enum MappingMode mode;
65
66 uint8_t **source_planes;
67 } ChannelMapContext;
68
69 #define OFFSET(x) offsetof(ChannelMapContext, x)
70 #define A AV_OPT_FLAG_AUDIO_PARAM
71 #define F AV_OPT_FLAG_FILTERING_PARAM
72 static const AVOption channelmap_options[] = {
73 { "map", "A comma-separated list of input channel numbers in output order.",
74 OFFSET(mapping_str), AV_OPT_TYPE_STRING, .flags = A|F },
75 { "channel_layout", "Output channel layout.",
76 OFFSET(output_layout), AV_OPT_TYPE_CHLAYOUT, .flags = A|F },
77 { NULL }
78 };
79
80 AVFILTER_DEFINE_CLASS(channelmap);
81
82 122 static void channelmap_uninit(AVFilterContext *ctx)
83 {
84 122 ChannelMapContext *s = ctx->priv;
85 122 av_freep(&s->map);
86 122 av_freep(&s->source_planes);
87 122 }
88
89 468 static char* split(char *message, char delim) {
90 468 char *next = strchr(message, delim);
91
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 468 if (next)
92 350 *next++ = '\0';
93 468 return next;
94 }
95
96 200 static int get_channel_idx(char **map, int *ch, char delim)
97 {
98 char *next;
99 int len;
100 200 int n = 0;
101
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 200 if (!*map)
102 ✗ return AVERROR(EINVAL);
103 200 next = split(*map, delim);
104
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 200 if (!next && delim == '-')
105 ✗ return AVERROR(EINVAL);
106 200 len = strlen(*map);
107 200 sscanf(*map, "%d%n", ch, &n);
108
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 200 if (n != len)
109 ✗ return AVERROR(EINVAL);
110
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 200 if (*ch < 0)
111 ✗ return AVERROR(EINVAL);
112 200 *map = next;
113 200 return 0;
114 }
115
116 268 static int get_channel(char **map, int *ch, char delim)
117 {
118 268 char *next = split(*map, delim);
119
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 268 if (!next && delim == '-')
120 ✗ return AVERROR(EINVAL);
121 268 *ch = av_channel_from_string(*map);
122
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 268 if (*ch < 0)
123 ✗ return AVERROR(EINVAL);
124 268 *map = next;
125 268 return 0;
126 }
127
128 528 static int check_idx_and_id(AVFilterContext *ctx, int channel_idx, int channel, AVChannelLayout *ch_layout, const char *io)
129 {
130 char channel_name[64];
131 char layout_name[256];
132 528 int nb_channels = ch_layout->nb_channels;
133
134
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 528 if (channel_idx < 0 || channel_idx >= nb_channels) {
135 ✗ av_channel_layout_describe(ch_layout, layout_name, sizeof(layout_name));
136 ✗ if (channel >= 0) {
137 ✗ av_channel_name(channel_name, sizeof(channel_name), channel);
138 ✗ av_log(ctx, AV_LOG_ERROR,
139 "%sput channel '%s' not available from %sput layout '%s'\n",
140 io, channel_name, io, layout_name);
141 } else {
142 ✗ av_log(ctx, AV_LOG_ERROR,
143 "%sput channel #%d not available from %sput layout '%s'\n",
144 io, channel_idx, io, layout_name);
145 }
146 ✗ return AVERROR(EINVAL);
147 }
148
149 528 return 0;
150 }
151
152 122 static av_cold int channelmap_init(AVFilterContext *ctx)
153 {
154 122 ChannelMapContext *s = ctx->priv;
155 122 char *mapping, separator = '|';
156 122 int map_entries = 0;
157 enum MappingMode mode;
158 122 int64_t out_ch_mask = 0;
159 122 uint8_t *presence_map = NULL;
160 122 int ret = 0;
161 int i;
162
163 122 mapping = s->mapping_str;
164
165
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 122 if (!mapping) {
166 4 mode = MAP_NONE;
167 } else {
168 118 char *dash = strchr(mapping, '-');
169
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 118 if (!dash) { // short mapping
170
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 116 if (av_isdigit(*mapping))
171 114 mode = MAP_ONE_INT;
172 else
173 2 mode = MAP_ONE_STR;
174
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 2 } else if (av_isdigit(*mapping)) {
175 ✗ if (av_isdigit(*(dash+1)))
176 ✗ mode = MAP_PAIR_INT_INT;
177 else
178 ✗ mode = MAP_PAIR_INT_STR;
179 } else {
180
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 2 if (av_isdigit(*(dash+1)))
181 ✗ mode = MAP_PAIR_STR_INT;
182 else
183 2 mode = MAP_PAIR_STR_STR;
184 }
185 }
186
187
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 122 if (mode != MAP_NONE) {
188 118 char *sep = mapping;
189 118 map_entries = 1;
190
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 336 while ((sep = strchr(sep, separator))) {
191
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 218 if (*++sep) // Allow trailing comma
192 218 map_entries++;
193 }
194
195 118 s->map = av_malloc_array(map_entries, sizeof(*s->map));
196
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 118 if (!s->map)
197 ✗ return AVERROR(ENOMEM);
198 }
199
200
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 458 for (i = 0; i < map_entries; i++) {
201 336 int in_ch_idx = -1, out_ch_idx = -1;
202 336 int in_ch = -1, out_ch = -1;
203 static const char err[] = "Failed to parse channel map\n";
204
205 336 s->map[i].in_channel_idx = -1;
206 336 s->map[i].out_channel_idx = -1;
207 336 s->map[i].in_channel = -1;
208 336 s->map[i].out_channel = -1;
209
210
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 336 switch (mode) {
211 200 case MAP_ONE_INT:
212
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 200 if (get_channel_idx(&mapping, &in_ch_idx, separator) < 0) {
213 ✗ av_log(ctx, AV_LOG_ERROR, err);
214 ✗ return AVERROR(EINVAL);
215 }
216 200 s->map[i].in_channel_idx = in_ch_idx;
217 200 s->map[i].out_channel_idx = i;
218 200 break;
219 4 case MAP_ONE_STR:
220
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 4 if (get_channel(&mapping, &in_ch, separator) < 0) {
221 ✗ av_log(ctx, AV_LOG_ERROR, err);
222 ✗ return AVERROR(EINVAL);
223 }
224 4 s->map[i].in_channel = in_ch;
225 4 s->map[i].out_channel_idx = i;
226 4 break;
227 ✗ case MAP_PAIR_INT_INT:
228 ✗ if (get_channel_idx(&mapping, &in_ch_idx, '-') < 0 ||
229 ✗ get_channel_idx(&mapping, &out_ch_idx, separator) < 0) {
230 ✗ av_log(ctx, AV_LOG_ERROR, err);
231 ✗ return AVERROR(EINVAL);
232 }
233 ✗ s->map[i].in_channel_idx = in_ch_idx;
234 ✗ s->map[i].out_channel_idx = out_ch_idx;
235 ✗ break;
236 ✗ case MAP_PAIR_INT_STR:
237 ✗ if (get_channel_idx(&mapping, &in_ch_idx, '-') < 0 ||
238 ✗ get_channel(&mapping, &out_ch, separator) < 0) {
239 ✗ av_log(ctx, AV_LOG_ERROR, err);
240 ✗ return AVERROR(EINVAL);
241 }
242 ✗ s->map[i].in_channel_idx = in_ch_idx;
243 ✗ s->map[i].out_channel = out_ch;
244 ✗ if (out_ch < 63)
245 ✗ out_ch_mask |= 1ULL << out_ch;
246 else
247 ✗ out_ch_mask = -1;
248 ✗ break;
249 ✗ case MAP_PAIR_STR_INT:
250 ✗ if (get_channel(&mapping, &in_ch, '-') < 0 ||
251 ✗ get_channel_idx(&mapping, &out_ch_idx, separator) < 0) {
252 ✗ av_log(ctx, AV_LOG_ERROR, err);
253 ✗ return AVERROR(EINVAL);
254 }
255 ✗ s->map[i].in_channel = in_ch;
256 ✗ s->map[i].out_channel_idx = out_ch_idx;
257 ✗ break;
258 132 case MAP_PAIR_STR_STR:
259
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 264 if (get_channel(&mapping, &in_ch, '-') < 0 ||
260 132 get_channel(&mapping, &out_ch, separator) < 0) {
261 ✗ av_log(ctx, AV_LOG_ERROR, err);
262 ✗ return AVERROR(EINVAL);
263 }
264 132 s->map[i].in_channel = in_ch;
265 132 s->map[i].out_channel = out_ch;
266
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 132 if (out_ch < 63)
267 4 out_ch_mask |= 1ULL << out_ch;
268 else
269 128 out_ch_mask = -1;
270 132 break;
271 }
272 }
273 122 s->mode = mode;
274 122 s->nch = map_entries;
275
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 122 if (s->output_layout.nb_channels == 0) {
276 ✗ if (out_ch_mask > 0)
277 ✗ av_channel_layout_from_mask(&s->output_layout, out_ch_mask);
278 ✗ else if (map_entries)
279 ✗ av_channel_layout_default(&s->output_layout, map_entries);
280 }
281
282
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 122 if (mode == MAP_NONE) {
283 int i;
284 4 s->nch = s->output_layout.nb_channels;
285
286 4 s->map = av_malloc_array(s->nch, sizeof(*s->map));
287
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 4 if (!s->map)
288 ✗ return AVERROR(ENOMEM);
289
290
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 20 for (i = 0; i < s->nch; i++) {
291 16 s->map[i].in_channel_idx = i;
292 16 s->map[i].out_channel_idx = i;
293 16 s->map[i].out_channel = av_channel_layout_channel_from_index(&s->output_layout, i);
294 }
295
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 118 } else if (s->nch != s->output_layout.nb_channels) {
296 char buf[256];
297 ✗ av_channel_layout_describe(&s->output_layout, buf, sizeof(buf));
298 ✗ av_log(ctx, AV_LOG_ERROR,
299 "Output channel layout %s does not match the number of channels mapped %d.\n",
300 buf, s->nch);
301 ✗ return AVERROR(EINVAL);
302 }
303
304
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 122 if (!s->output_layout.nb_channels) {
305 ✗ av_log(ctx, AV_LOG_ERROR, "Output channel layout is not set and "
306 "cannot be guessed from the maps.\n");
307 ✗ return AVERROR(EINVAL);
308 }
309
310
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 122 if (mode == MAP_PAIR_INT_STR || mode == MAP_PAIR_STR_STR) {
311
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 134 for (i = 0; i < s->nch; i++) {
312 132 s->map[i].out_channel_idx = av_channel_layout_index_from_channel(
313 132 &s->output_layout, s->map[i].out_channel);
314 }
315 }
316
317 122 presence_map = av_calloc(s->nch, sizeof(*presence_map));
318
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 474 for (i = 0; i < s->nch; i++) {
319 352 const int out_idx = s->map[i].out_channel_idx;
320 352 ret = check_idx_and_id(ctx, out_idx, s->map[i].out_channel, &s->output_layout, "out");
321
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 352 if (ret < 0)
322 ✗ break;
323
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 352 if (presence_map[out_idx]) {
324 char layout_name[256];
325 ✗ av_channel_layout_describe(&s->output_layout, layout_name, sizeof(layout_name));
326 ✗ av_log(ctx, AV_LOG_ERROR, "Mapping %d assigns channel #%d twice in output layout '%s'.\n",
327 ✗ i + 1, s->map[i].out_channel_idx, layout_name);
328 ✗ ret = AVERROR(EINVAL);
329 ✗ break;
330 }
331 352 presence_map[out_idx] = 1;
332 }
333 122 av_freep(&presence_map);
334
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 122 if (ret < 0)
335 ✗ return ret;
336
337 122 return 0;
338 }
339
340 61 static int channelmap_query_formats(const AVFilterContext *ctx,
341 AVFilterFormatsConfig **cfg_in,
342 AVFilterFormatsConfig **cfg_out)
343 {
344 61 const ChannelMapContext *s = ctx->priv;
345 61 AVFilterChannelLayouts *channel_layouts = NULL;
346
347 int ret;
348
349 61 ret = ff_set_common_formats2(ctx, cfg_in, cfg_out, ff_planar_sample_fmts());
350
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 61 if (ret < 0)
351 ✗ return ret;
352
353 61 ret = ff_add_channel_layout(&channel_layouts, &s->output_layout);
354
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 61 if (ret < 0)
355 ✗ return ret;
356
357 61 ret = ff_channel_layouts_ref(channel_layouts, &cfg_out[0]->channel_layouts);
358
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 61 if (ret < 0)
359 ✗ return ret;
360
361 61 return 0;
362 }
363
364 874 static int channelmap_filter_frame(AVFilterLink *inlink, AVFrame *buf)
365 {
366 874 AVFilterContext *ctx = inlink->dst;
367 874 AVFilterLink *outlink = ctx->outputs[0];
368 874 const ChannelMapContext *s = ctx->priv;
369 874 const int nch_in = inlink->ch_layout.nb_channels;
370 874 const int nch_out = s->nch;
371 int ch, ret;
372
373 874 memcpy(s->source_planes, buf->extended_data,
374 nch_in * sizeof(s->source_planes[0]));
375
376
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 874 if (nch_out > nch_in) {
377 ✗ if (nch_out > FF_ARRAY_ELEMS(buf->data)) {
378 uint8_t **new_extended_data =
379 ✗ av_calloc(nch_out, sizeof(*buf->extended_data));
380 ✗ if (!new_extended_data) {
381 ✗ av_frame_free(&buf);
382 ✗ return AVERROR(ENOMEM);
383 }
384 ✗ if (buf->extended_data == buf->data) {
385 ✗ buf->extended_data = new_extended_data;
386 } else {
387 ✗ av_free(buf->extended_data);
388 ✗ buf->extended_data = new_extended_data;
389 }
390 ✗ } else if (buf->extended_data != buf->data) {
391 ✗ av_free(buf->extended_data);
392 ✗ buf->extended_data = buf->data;
393 }
394 }
395
396
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 3096 for (ch = 0; ch < nch_out; ch++) {
397 2222 buf->extended_data[s->map[ch].out_channel_idx] =
398 2222 s->source_planes[s->map[ch].in_channel_idx];
399 }
400
401
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 874 if (buf->data != buf->extended_data)
402 517 memcpy(buf->data, buf->extended_data,
403
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 517 FFMIN(FF_ARRAY_ELEMS(buf->data), nch_out) * sizeof(buf->data[0]));
404
405
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 874 if ((ret = av_channel_layout_copy(&buf->ch_layout, &outlink->ch_layout)) < 0)
406 ✗ return ret;
407
408 874 return ff_filter_frame(outlink, buf);
409 }
410
411 61 static int channelmap_config_input(AVFilterLink *inlink)
412 {
413 61 AVFilterContext *ctx = inlink->dst;
414 61 ChannelMapContext *s = ctx->priv;
415 61 int i, err = 0;
416
417
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 237 for (i = 0; i < s->nch; i++) {
418 176 struct ChannelMap *m = &s->map[i];
419
420
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 176 if (s->mode == MAP_PAIR_STR_INT || s->mode == MAP_PAIR_STR_STR || s->mode == MAP_ONE_STR) {
421 68 m->in_channel_idx = av_channel_layout_index_from_channel(
422 68 &inlink->ch_layout, m->in_channel);
423 }
424
425
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 176 if (check_idx_and_id(ctx, m->in_channel_idx, m->in_channel, &inlink->ch_layout, "in") < 0)
426 ✗ err = AVERROR(EINVAL);
427 }
428
429 61 av_freep(&s->source_planes);
430 61 s->source_planes = av_calloc(inlink->ch_layout.nb_channels,
431 sizeof(*s->source_planes));
432
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 61 if (!s->source_planes)
433 ✗ return AVERROR(ENOMEM);
434
435 61 return err;
436 }
437
438 static const AVFilterPad avfilter_af_channelmap_inputs[] = {
439 {
440 .name = "default",
441 .type = AVMEDIA_TYPE_AUDIO,
442 .flags = AVFILTERPAD_FLAG_NEEDS_WRITABLE,
443 .filter_frame = channelmap_filter_frame,
444 .config_props = channelmap_config_input,
445 },
446 };
447
448 const FFFilter ff_af_channelmap = {
449 .p.name = "channelmap",
450 .p.description = NULL_IF_CONFIG_SMALL("Remap audio channels."),
451 .p.priv_class = &channelmap_class,
452 .init = channelmap_init,
453 .uninit = channelmap_uninit,
454 .priv_size = sizeof(ChannelMapContext),
455 FILTER_INPUTS(avfilter_af_channelmap_inputs),
456 FILTER_OUTPUTS(ff_audio_default_filterpad),
457 FILTER_QUERY_FUNC2(channelmap_query_formats),
458 };
459