doc/filters: update documentation.
[libav.git] / libavfilter / graphparser.c
CommitLineData
27afb09d
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1/*
2 * filter graph parser
3fa77bde
SS
3 * Copyright (c) 2008 Vitor Sessak
4 * Copyright (c) 2007 Bobby Bingham
27afb09d 5 *
2912e87a 6 * This file is part of Libav.
27afb09d 7 *
2912e87a 8 * Libav is free software; you can redistribute it and/or
27afb09d
VS
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 *
2912e87a 13 * Libav is distributed in the hope that it will be useful,
27afb09d
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14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
2912e87a 19 * License along with Libav; if not, write to the Free Software
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20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23#include <ctype.h>
24#include <string.h>
25
372e2884 26#include "libavutil/avstring.h"
27afb09d
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27#include "avfilter.h"
28#include "avfiltergraph.h"
29
fd548e5b
SS
30#define WHITESPACES " \n\t"
31
d2874a9d
SS
32/**
33 * Link two filters together.
34 *
35 * @see avfilter_link()
36 */
9710beaf 37static int link_filter(AVFilterContext *src, int srcpad,
3a70bb2d 38 AVFilterContext *dst, int dstpad,
64abd375 39 void *log_ctx)
27afb09d 40{
99ac59ca
SS
41 int ret;
42 if ((ret = avfilter_link(src, srcpad, dst, dstpad))) {
3a70bb2d 43 av_log(log_ctx, AV_LOG_ERROR,
bb90d855 44 "Cannot create the link %s:%d -> %s:%d\n",
9710beaf 45 src->filter->name, srcpad, dst->filter->name, dstpad);
99ac59ca 46 return ret;
27afb09d
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47 }
48
49 return 0;
50}
51
27afb09d 52/**
94b2120d
SS
53 * Parse the name of a link, which has the format "[linkname]".
54 *
55 * @return a pointer (that need to be freed after use) to the name
56 * between parenthesis
27afb09d 57 */
64abd375 58static char *parse_link_name(const char **buf, void *log_ctx)
27afb09d 59{
22260824 60 const char *start = *buf;
bd80b349 61 char *name;
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62 (*buf)++;
63
dd04911c 64 name = av_get_token(buf, "]");
27afb09d 65
f219eee5 66 if (!name[0]) {
3a70bb2d 67 av_log(log_ctx, AV_LOG_ERROR,
22260824 68 "Bad (empty?) label found in the following: \"%s\".\n", start);
27afb09d 69 goto fail;
22260824 70 }
27afb09d 71
f219eee5 72 if (*(*buf)++ != ']') {
3a70bb2d 73 av_log(log_ctx, AV_LOG_ERROR,
22260824 74 "Mismatched '[' found in the following: \"%s\".\n", start);
85cb8af7 75 fail:
bd80b349 76 av_freep(&name);
22260824 77 }
bd80b349
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78
79 return name;
27afb09d
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80}
81
98137a1a
SS
82/**
83 * Create an instance of a filter, initialize and insert it in the
84 * filtergraph in *ctx.
85 *
24c9baba 86 * @param filt_ctx put here a filter context in case of successful creation and configuration, NULL otherwise.
98137a1a
SS
87 * @param ctx the filtergraph context
88 * @param index an index which is supposed to be unique for each filter instance added to the filtergraph
89 * @param filt_name the name of the filter to create
90 * @param args the arguments provided to the filter during its initialization
91 * @param log_ctx the log context to use
c58572f8 92 * @return 0 in case of success, a negative AVERROR code otherwise
98137a1a 93 */
c58572f8 94static int create_filter(AVFilterContext **filt_ctx, AVFilterGraph *ctx, int index,
64abd375 95 const char *filt_name, const char *args, void *log_ctx)
8e74c889 96{
e4a5f397 97 AVFilter *filt;
8e74c889 98 char inst_name[30];
b5049814 99 char tmp_args[256];
c58572f8 100 int ret;
8e74c889 101
3bf3fc0e 102 snprintf(inst_name, sizeof(inst_name), "Parsed filter %d %s", index, filt_name);
8e74c889 103
e4a5f397 104 filt = avfilter_get_by_name(filt_name);
5e600185 105
f219eee5 106 if (!filt) {
8e74c889 107 av_log(log_ctx, AV_LOG_ERROR,
bb90d855 108 "No such filter: '%s'\n", filt_name);
c58572f8 109 return AVERROR(EINVAL);
8e74c889
VS
110 }
111
c58572f8
SS
112 ret = avfilter_open(filt_ctx, filt, inst_name);
113 if (!*filt_ctx) {
8e74c889 114 av_log(log_ctx, AV_LOG_ERROR,
bb90d855 115 "Error creating filter '%s'\n", filt_name);
c58572f8 116 return ret;
8e74c889
VS
117 }
118
c58572f8 119 if ((ret = avfilter_graph_add_filter(ctx, *filt_ctx)) < 0) {
24de0edb 120 avfilter_free(*filt_ctx);
c58572f8 121 return ret;
64b164f4 122 }
8e74c889 123
f80b381b 124 if (!strcmp(filt_name, "scale") && args && !strstr(args, "flags")) {
b5049814
BC
125 snprintf(tmp_args, sizeof(tmp_args), "%s:%s",
126 args, ctx->scale_sws_opts);
127 args = tmp_args;
128 }
129
c58572f8 130 if ((ret = avfilter_init_filter(*filt_ctx, args, NULL)) < 0) {
8e74c889 131 av_log(log_ctx, AV_LOG_ERROR,
bb90d855 132 "Error initializing filter '%s' with args '%s'\n", filt_name, args);
c58572f8 133 return ret;
8e74c889
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134 }
135
c58572f8 136 return 0;
8e74c889
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137}
138
f5cbde2e 139/**
55b2a9ba
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140 * Parse a string of the form FILTER_NAME[=PARAMS], and create a
141 * corresponding filter instance which is added to graph with
142 * create_filter().
143 *
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DB
144 * @param filt_ctx Pointer that is set to the created and configured filter
145 * context on success, set to NULL on failure.
55b2a9ba
SS
146 * @param filt_ctx put here a pointer to the created filter context on
147 * success, NULL otherwise
148 * @param buf pointer to the buffer to parse, *buf will be updated to
149 * point to the char next after the parsed string
150 * @param index an index which is assigned to the created filter
151 * instance, and which is supposed to be unique for each filter
152 * instance added to the filtergraph
153 * @return 0 in case of success, a negative AVERROR code otherwise
f5cbde2e 154 */
688b9dad 155static int parse_filter(AVFilterContext **filt_ctx, const char **buf, AVFilterGraph *graph,
64abd375 156 int index, void *log_ctx)
f5cbde2e 157{
ba3fed2f 158 char *opts = NULL;
15a316c0 159 char *name = av_get_token(buf, "=,;[\n");
c58572f8 160 int ret;
f5cbde2e 161
f219eee5 162 if (**buf == '=') {
f5cbde2e 163 (*buf)++;
15a316c0 164 opts = av_get_token(buf, "[],;\n");
12849837 165 }
f5cbde2e 166
688b9dad 167 ret = create_filter(filt_ctx, graph, index, name, opts, log_ctx);
64b164f4
VS
168 av_free(name);
169 av_free(opts);
688b9dad 170 return ret;
f5cbde2e
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171}
172
91d3cbe0 173AVFilterInOut *avfilter_inout_alloc(void)
27afb09d 174{
91d3cbe0
SS
175 return av_mallocz(sizeof(AVFilterInOut));
176}
177
178void avfilter_inout_free(AVFilterInOut **inout)
179{
180 while (*inout) {
181 AVFilterInOut *next = (*inout)->next;
182 av_freep(&(*inout)->name);
183 av_freep(inout);
184 *inout = next;
27afb09d
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185 }
186}
187
c9987633
VS
188static AVFilterInOut *extract_inout(const char *label, AVFilterInOut **links)
189{
190 AVFilterInOut *ret;
c9987633 191
d7bcc71d 192 while (*links && (!(*links)->name || strcmp((*links)->name, label)))
f6557d5e 193 links = &((*links)->next);
c9987633 194
f6557d5e 195 ret = *links;
c9987633 196
d7bcc71d 197 if (ret) {
f6557d5e 198 *links = ret->next;
d7bcc71d
AK
199 ret->next = NULL;
200 }
c9987633
VS
201
202 return ret;
203}
204
e97908ee
VS
205static void insert_inout(AVFilterInOut **inouts, AVFilterInOut *element)
206{
207 element->next = *inouts;
208 *inouts = element;
209}
c9987633 210
d7bcc71d
AK
211static void append_inout(AVFilterInOut **inouts, AVFilterInOut **element)
212{
213 while (*inouts && (*inouts)->next)
214 inouts = &((*inouts)->next);
215
216 if (!*inouts)
217 *inouts = *element;
218 else
219 (*inouts)->next = *element;
220 *element = NULL;
221}
222
ed581e65 223static int link_filter_inouts(AVFilterContext *filt_ctx,
7f9b3266 224 AVFilterInOut **curr_inputs,
64abd375 225 AVFilterInOut **open_inputs, void *log_ctx)
c9987633 226{
4e781c25 227 int pad, ret;
c9987633 228
4e781c25 229 for (pad = 0; pad < filt_ctx->input_count; pad++) {
7f9b3266 230 AVFilterInOut *p = *curr_inputs;
c9987633 231
d7bcc71d
AK
232 if (p)
233 *curr_inputs = (*curr_inputs)->next;
234 else if (!(p = av_mallocz(sizeof(*p))))
235 return AVERROR(ENOMEM);
4d11beb2 236
7313132b
SS
237 if (p->filter_ctx) {
238 if ((ret = link_filter(p->filter_ctx, p->pad_idx, filt_ctx, pad, log_ctx)) < 0)
684ade49 239 return ret;
64b164f4 240 av_free(p->name);
c9987633
VS
241 av_free(p);
242 } else {
7313132b 243 p->filter_ctx = filt_ctx;
c9987633 244 p->pad_idx = pad;
7af99a01 245 append_inout(open_inputs, &p);
c9987633
VS
246 }
247 }
248
f219eee5 249 if (*curr_inputs) {
c9987633
VS
250 av_log(log_ctx, AV_LOG_ERROR,
251 "Too many inputs specified for the \"%s\" filter.\n",
ed581e65 252 filt_ctx->filter->name);
684ade49 253 return AVERROR(EINVAL);
c9987633
VS
254 }
255
ed581e65 256 pad = filt_ctx->output_count;
f219eee5 257 while (pad--) {
c956dd43 258 AVFilterInOut *currlinkn = av_mallocz(sizeof(AVFilterInOut));
fbd97184
SS
259 if (!currlinkn)
260 return AVERROR(ENOMEM);
7313132b 261 currlinkn->filter_ctx = filt_ctx;
c9987633 262 currlinkn->pad_idx = pad;
7f9b3266 263 insert_inout(curr_inputs, currlinkn);
c9987633
VS
264 }
265
266 return 0;
267}
268
7f9b3266 269static int parse_inputs(const char **buf, AVFilterInOut **curr_inputs,
64abd375 270 AVFilterInOut **open_outputs, void *log_ctx)
27afb09d 271{
4e781c25 272 AVFilterInOut *parsed_inputs = NULL;
c9987633 273 int pad = 0;
c9987633 274
f219eee5 275 while (**buf == '[') {
bd80b349 276 char *name = parse_link_name(buf, log_ctx);
b2ac16da 277 AVFilterInOut *match;
22260824 278
f219eee5 279 if (!name)
42e7f6d7 280 return AVERROR(EINVAL);
22260824 281
7f9b3266
SS
282 /* First check if the label is not in the open_outputs list */
283 match = extract_inout(name, open_outputs);
cf4f7d38 284
f219eee5 285 if (match) {
64fbf5e2 286 av_free(name);
0de3407b
VS
287 } else {
288 /* Not in the list, so add it as an input */
00b3ca3c
SS
289 if (!(match = av_mallocz(sizeof(AVFilterInOut))))
290 return AVERROR(ENOMEM);
c880791f 291 match->name = name;
c880791f 292 match->pad_idx = pad;
cf4f7d38 293 }
e97908ee 294
4e781c25 295 append_inout(&parsed_inputs, &match);
e97908ee 296
fd548e5b 297 *buf += strspn(*buf, WHITESPACES);
c9987633 298 pad++;
27afb09d 299 }
cf4f7d38 300
4e781c25
AK
301 append_inout(&parsed_inputs, curr_inputs);
302 *curr_inputs = parsed_inputs;
303
27afb09d
VS
304 return pad;
305}
306
7f9b3266
SS
307static int parse_outputs(const char **buf, AVFilterInOut **curr_inputs,
308 AVFilterInOut **open_inputs,
64abd375 309 AVFilterInOut **open_outputs, void *log_ctx)
9710beaf 310{
0cc8b659 311 int ret, pad = 0;
c9987633 312
f219eee5 313 while (**buf == '[') {
bd80b349 314 char *name = parse_link_name(buf, log_ctx);
c9987633
VS
315 AVFilterInOut *match;
316
7f9b3266 317 AVFilterInOut *input = *curr_inputs;
668673f1
SS
318 if (!input) {
319 av_log(log_ctx, AV_LOG_ERROR,
320 "No output pad can be associated to link label '%s'.\n",
321 name);
322 return AVERROR(EINVAL);
323 }
7f9b3266 324 *curr_inputs = (*curr_inputs)->next;
443c10ef 325
f219eee5 326 if (!name)
0cc8b659 327 return AVERROR(EINVAL);
c9987633 328
7f9b3266
SS
329 /* First check if the label is not in the open_inputs list */
330 match = extract_inout(name, open_inputs);
c9987633 331
f219eee5 332 if (match) {
7313132b
SS
333 if ((ret = link_filter(input->filter_ctx, input->pad_idx,
334 match->filter_ctx, match->pad_idx, log_ctx)) < 0)
0cc8b659 335 return ret;
64b164f4
VS
336 av_free(match->name);
337 av_free(name);
c9987633 338 av_free(match);
7baa6210 339 av_free(input);
0de3407b 340 } else {
7f9b3266 341 /* Not in the list, so add the first input as a open_output */
7baa6210 342 input->name = name;
7f9b3266 343 insert_inout(open_outputs, input);
c9987633 344 }
fd548e5b 345 *buf += strspn(*buf, WHITESPACES);
c9987633 346 pad++;
8095a014 347 }
9710beaf 348
c9987633
VS
349 return pad;
350}
9710beaf 351
d7bcc71d
AK
352#if FF_API_GRAPH_AVCLASS
353#define log_ctx graph
354#else
355#define log_ctx NULL
356#endif
12e7e1d0
AK
357
358static int parse_sws_flags(const char **buf, AVFilterGraph *graph)
359{
360 char *p = strchr(*buf, ';');
361
362 if (strncmp(*buf, "sws_flags=", 10))
363 return 0;
364
365 if (!p) {
366 av_log(log_ctx, AV_LOG_ERROR, "sws_flags not terminated with ';'.\n");
367 return AVERROR(EINVAL);
368 }
369
370 *buf += 4; // keep the 'flags=' part
371
372 av_freep(&graph->scale_sws_opts);
373 if (!(graph->scale_sws_opts = av_mallocz(p - *buf + 1)))
374 return AVERROR(ENOMEM);
375 av_strlcpy(graph->scale_sws_opts, *buf, p - *buf + 1);
376
377 *buf = p + 1;
378 return 0;
379}
380
d7bcc71d
AK
381int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
382 AVFilterInOut **inputs,
383 AVFilterInOut **outputs)
27afb09d 384{
c24f76b9 385 int index = 0, ret;
27afb09d 386 char chr = 0;
27afb09d 387
d7bcc71d 388 AVFilterInOut *curr_inputs = NULL, *open_inputs = NULL, *open_outputs = NULL;
27afb09d 389
12e7e1d0
AK
390 filters += strspn(filters, WHITESPACES);
391
392 if ((ret = parse_sws_flags(&filters, graph)) < 0)
393 goto fail;
394
27afb09d 395 do {
9710beaf 396 AVFilterContext *filter;
fd548e5b 397 filters += strspn(filters, WHITESPACES);
27afb09d 398
c24f76b9 399 if ((ret = parse_inputs(&filters, &curr_inputs, &open_outputs, log_ctx)) < 0)
27afb09d
VS
400 goto fail;
401
c24f76b9 402 if ((ret = parse_filter(&filter, &filters, graph, index, log_ctx)) < 0)
22260824
VS
403 goto fail;
404
27afb09d 405
c24f76b9 406 if ((ret = link_filter_inouts(filter, &curr_inputs, &open_inputs, log_ctx)) < 0)
c9987633 407 goto fail;
da790674 408
c24f76b9
SS
409 if ((ret = parse_outputs(&filters, &curr_inputs, &open_inputs, &open_outputs,
410 log_ctx)) < 0)
e84f0b62
VS
411 goto fail;
412
fd548e5b 413 filters += strspn(filters, WHITESPACES);
27afb09d 414 chr = *filters++;
27afb09d 415
d7bcc71d
AK
416 if (chr == ';' && curr_inputs)
417 append_inout(&open_outputs, &curr_inputs);
c9987633 418 index++;
f219eee5 419 } while (chr == ',' || chr == ';');
27afb09d 420
fd51ff16 421 if (chr) {
78471234
SS
422 av_log(log_ctx, AV_LOG_ERROR,
423 "Unable to parse graph description substring: \"%s\"\n",
424 filters - 1);
c24f76b9 425 ret = AVERROR(EINVAL);
78471234
SS
426 goto fail;
427 }
428
d7bcc71d 429 append_inout(&open_outputs, &curr_inputs);
27afb09d 430
d7bcc71d
AK
431 *inputs = open_inputs;
432 *outputs = open_outputs;
27afb09d
VS
433 return 0;
434
435 fail:
e8e5dde7
SS
436 for (; graph->filter_count > 0; graph->filter_count--)
437 avfilter_free(graph->filters[graph->filter_count - 1]);
438 av_freep(&graph->filters);
91d3cbe0
SS
439 avfilter_inout_free(&open_inputs);
440 avfilter_inout_free(&open_outputs);
441 avfilter_inout_free(&curr_inputs);
d7bcc71d
AK
442
443 *inputs = NULL;
444 *outputs = NULL;
445
446 return ret;
447}
448#undef log_ctx
449
450int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
451 AVFilterInOut *open_inputs,
452 AVFilterInOut *open_outputs, void *log_ctx)
453{
454 int ret;
455 AVFilterInOut *cur, *match, *inputs = NULL, *outputs = NULL;
456
457 if ((ret = avfilter_graph_parse2(graph, filters, &inputs, &outputs)) < 0)
458 goto fail;
459
460 /* First input can be omitted if it is "[in]" */
461 if (inputs && !inputs->name)
462 inputs->name = av_strdup("in");
463 for (cur = inputs; cur; cur = cur->next) {
464 if (!cur->name) {
465 av_log(log_ctx, AV_LOG_ERROR,
466 "Not enough inputs specified for the \"%s\" filter.\n",
467 cur->filter_ctx->filter->name);
468 ret = AVERROR(EINVAL);
469 goto fail;
470 }
471 if (!(match = extract_inout(cur->name, &open_outputs)))
472 continue;
473 ret = avfilter_link(match->filter_ctx, match->pad_idx,
474 cur->filter_ctx, cur->pad_idx);
91d3cbe0 475 avfilter_inout_free(&match);
d7bcc71d
AK
476 if (ret < 0)
477 goto fail;
478 }
479
480 /* Last output can be omitted if it is "[out]" */
481 if (outputs && !outputs->name)
482 outputs->name = av_strdup("out");
483 for (cur = outputs; cur; cur = cur->next) {
484 if (!cur->name) {
485 av_log(log_ctx, AV_LOG_ERROR,
486 "Invalid filterchain containing an unlabelled output pad: \"%s\"\n",
487 filters);
488 ret = AVERROR(EINVAL);
489 goto fail;
490 }
491 if (!(match = extract_inout(cur->name, &open_inputs)))
492 continue;
493 ret = avfilter_link(cur->filter_ctx, cur->pad_idx,
494 match->filter_ctx, match->pad_idx);
91d3cbe0 495 avfilter_inout_free(&match);
d7bcc71d
AK
496 if (ret < 0)
497 goto fail;
498 }
499
500 fail:
501 if (ret < 0) {
502 for (; graph->filter_count > 0; graph->filter_count--)
503 avfilter_free(graph->filters[graph->filter_count - 1]);
504 av_freep(&graph->filters);
505 }
91d3cbe0
SS
506 avfilter_inout_free(&inputs);
507 avfilter_inout_free(&outputs);
508 avfilter_inout_free(&open_inputs);
509 avfilter_inout_free(&open_outputs);
c24f76b9 510 return ret;
27afb09d 511}