vsrc_buffer: allow using a NULL buffer to signal EOF.
[libav.git] / libavfilter / graphparser.c
CommitLineData
27afb09d
VS
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
VS
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
27afb09d
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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
VS
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;
27afb09d
VS
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
VS
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
VS
134 }
135
c58572f8 136 return 0;
8e74c889
VS
137}
138
f5cbde2e 139/**
55b2a9ba
SS
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 *
96c1e6d4
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
VS
171}
172
27afb09d
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173static void free_inout(AVFilterInOut *head)
174{
f219eee5 175 while (head) {
55672c83 176 AVFilterInOut *next = head->next;
64b164f4 177 av_free(head->name);
27afb09d
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178 av_free(head);
179 head = next;
180 }
181}
182
c9987633
VS
183static AVFilterInOut *extract_inout(const char *label, AVFilterInOut **links)
184{
185 AVFilterInOut *ret;
c9987633 186
f219eee5 187 while (*links && strcmp((*links)->name, label))
f6557d5e 188 links = &((*links)->next);
c9987633 189
f6557d5e 190 ret = *links;
c9987633 191
f219eee5 192 if (ret)
f6557d5e 193 *links = ret->next;
c9987633
VS
194
195 return ret;
196}
197
e97908ee
VS
198static void insert_inout(AVFilterInOut **inouts, AVFilterInOut *element)
199{
200 element->next = *inouts;
201 *inouts = element;
202}
c9987633 203
ed581e65 204static int link_filter_inouts(AVFilterContext *filt_ctx,
7f9b3266 205 AVFilterInOut **curr_inputs,
64abd375 206 AVFilterInOut **open_inputs, void *log_ctx)
c9987633 207{
ed581e65 208 int pad = filt_ctx->input_count, ret;
c9987633 209
f219eee5 210 while (pad--) {
7f9b3266 211 AVFilterInOut *p = *curr_inputs;
f219eee5 212 if (!p) {
c9987633
VS
213 av_log(log_ctx, AV_LOG_ERROR,
214 "Not enough inputs specified for the \"%s\" filter.\n",
ed581e65 215 filt_ctx->filter->name);
684ade49 216 return AVERROR(EINVAL);
c9987633
VS
217 }
218
7f9b3266 219 *curr_inputs = (*curr_inputs)->next;
4d11beb2 220
7313132b
SS
221 if (p->filter_ctx) {
222 if ((ret = link_filter(p->filter_ctx, p->pad_idx, filt_ctx, pad, log_ctx)) < 0)
684ade49 223 return ret;
64b164f4 224 av_free(p->name);
c9987633
VS
225 av_free(p);
226 } else {
7313132b 227 p->filter_ctx = filt_ctx;
c9987633 228 p->pad_idx = pad;
7f9b3266 229 insert_inout(open_inputs, p);
c9987633
VS
230 }
231 }
232
f219eee5 233 if (*curr_inputs) {
c9987633
VS
234 av_log(log_ctx, AV_LOG_ERROR,
235 "Too many inputs specified for the \"%s\" filter.\n",
ed581e65 236 filt_ctx->filter->name);
684ade49 237 return AVERROR(EINVAL);
c9987633
VS
238 }
239
ed581e65 240 pad = filt_ctx->output_count;
f219eee5 241 while (pad--) {
c956dd43 242 AVFilterInOut *currlinkn = av_mallocz(sizeof(AVFilterInOut));
fbd97184
SS
243 if (!currlinkn)
244 return AVERROR(ENOMEM);
7313132b 245 currlinkn->filter_ctx = filt_ctx;
c9987633 246 currlinkn->pad_idx = pad;
7f9b3266 247 insert_inout(curr_inputs, currlinkn);
c9987633
VS
248 }
249
250 return 0;
251}
252
7f9b3266 253static int parse_inputs(const char **buf, AVFilterInOut **curr_inputs,
64abd375 254 AVFilterInOut **open_outputs, void *log_ctx)
27afb09d 255{
c9987633 256 int pad = 0;
c9987633 257
f219eee5 258 while (**buf == '[') {
bd80b349 259 char *name = parse_link_name(buf, log_ctx);
b2ac16da 260 AVFilterInOut *match;
22260824 261
f219eee5 262 if (!name)
42e7f6d7 263 return AVERROR(EINVAL);
22260824 264
7f9b3266
SS
265 /* First check if the label is not in the open_outputs list */
266 match = extract_inout(name, open_outputs);
cf4f7d38 267
f219eee5 268 if (match) {
64fbf5e2 269 av_free(name);
0de3407b
VS
270 } else {
271 /* Not in the list, so add it as an input */
00b3ca3c
SS
272 if (!(match = av_mallocz(sizeof(AVFilterInOut))))
273 return AVERROR(ENOMEM);
c880791f 274 match->name = name;
c880791f 275 match->pad_idx = pad;
cf4f7d38 276 }
e97908ee 277
7f9b3266 278 insert_inout(curr_inputs, match);
e97908ee 279
fd548e5b 280 *buf += strspn(*buf, WHITESPACES);
c9987633 281 pad++;
27afb09d 282 }
cf4f7d38 283
27afb09d
VS
284 return pad;
285}
286
7f9b3266
SS
287static int parse_outputs(const char **buf, AVFilterInOut **curr_inputs,
288 AVFilterInOut **open_inputs,
64abd375 289 AVFilterInOut **open_outputs, void *log_ctx)
9710beaf 290{
0cc8b659 291 int ret, pad = 0;
c9987633 292
f219eee5 293 while (**buf == '[') {
bd80b349 294 char *name = parse_link_name(buf, log_ctx);
c9987633
VS
295 AVFilterInOut *match;
296
7f9b3266 297 AVFilterInOut *input = *curr_inputs;
668673f1
SS
298 if (!input) {
299 av_log(log_ctx, AV_LOG_ERROR,
300 "No output pad can be associated to link label '%s'.\n",
301 name);
302 return AVERROR(EINVAL);
303 }
7f9b3266 304 *curr_inputs = (*curr_inputs)->next;
443c10ef 305
f219eee5 306 if (!name)
0cc8b659 307 return AVERROR(EINVAL);
c9987633 308
7f9b3266
SS
309 /* First check if the label is not in the open_inputs list */
310 match = extract_inout(name, open_inputs);
c9987633 311
f219eee5 312 if (match) {
7313132b
SS
313 if ((ret = link_filter(input->filter_ctx, input->pad_idx,
314 match->filter_ctx, match->pad_idx, log_ctx)) < 0)
0cc8b659 315 return ret;
64b164f4
VS
316 av_free(match->name);
317 av_free(name);
c9987633 318 av_free(match);
7baa6210 319 av_free(input);
0de3407b 320 } else {
7f9b3266 321 /* Not in the list, so add the first input as a open_output */
7baa6210 322 input->name = name;
7f9b3266 323 insert_inout(open_outputs, input);
c9987633 324 }
fd548e5b 325 *buf += strspn(*buf, WHITESPACES);
c9987633 326 pad++;
8095a014 327 }
9710beaf 328
c9987633
VS
329 return pad;
330}
9710beaf 331
86a47378 332int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
7f9b3266 333 AVFilterInOut *open_inputs,
57fa3140 334 AVFilterInOut *open_outputs, void *log_ctx)
27afb09d 335{
c24f76b9 336 int index = 0, ret;
27afb09d 337 char chr = 0;
27afb09d 338
7f9b3266 339 AVFilterInOut *curr_inputs = NULL;
27afb09d 340
27afb09d 341 do {
9710beaf 342 AVFilterContext *filter;
9241cd20 343 const char *filterchain = filters;
fd548e5b 344 filters += strspn(filters, WHITESPACES);
27afb09d 345
c24f76b9 346 if ((ret = parse_inputs(&filters, &curr_inputs, &open_outputs, log_ctx)) < 0)
27afb09d
VS
347 goto fail;
348
c24f76b9 349 if ((ret = parse_filter(&filter, &filters, graph, index, log_ctx)) < 0)
22260824
VS
350 goto fail;
351
f219eee5 352 if (filter->input_count == 1 && !curr_inputs && !index) {
e916c2ac 353 /* First input can be omitted if it is "[in]" */
c9987633 354 const char *tmp = "[in]";
c24f76b9 355 if ((ret = parse_inputs(&tmp, &curr_inputs, &open_outputs, log_ctx)) < 0)
27afb09d 356 goto fail;
27afb09d
VS
357 }
358
c24f76b9 359 if ((ret = link_filter_inouts(filter, &curr_inputs, &open_inputs, log_ctx)) < 0)
c9987633 360 goto fail;
da790674 361
c24f76b9
SS
362 if ((ret = parse_outputs(&filters, &curr_inputs, &open_inputs, &open_outputs,
363 log_ctx)) < 0)
e84f0b62
VS
364 goto fail;
365
fd548e5b 366 filters += strspn(filters, WHITESPACES);
27afb09d 367 chr = *filters++;
27afb09d 368
f219eee5 369 if (chr == ';' && curr_inputs) {
c9987633 370 av_log(log_ctx, AV_LOG_ERROR,
9241cd20
SS
371 "Invalid filterchain containing an unlabelled output pad: \"%s\"\n",
372 filterchain);
c24f76b9 373 ret = AVERROR(EINVAL);
c9987633 374 goto fail;
27afb09d 375 }
c9987633 376 index++;
f219eee5 377 } while (chr == ',' || chr == ';');
27afb09d 378
fd51ff16 379 if (chr) {
78471234
SS
380 av_log(log_ctx, AV_LOG_ERROR,
381 "Unable to parse graph description substring: \"%s\"\n",
382 filters - 1);
c24f76b9 383 ret = AVERROR(EINVAL);
78471234
SS
384 goto fail;
385 }
386
f219eee5 387 if (open_inputs && !strcmp(open_inputs->name, "out") && curr_inputs) {
e916c2ac 388 /* Last output can be omitted if it is "[out]" */
c9987633 389 const char *tmp = "[out]";
c24f76b9
SS
390 if ((ret = parse_outputs(&tmp, &curr_inputs, &open_inputs, &open_outputs,
391 log_ctx)) < 0)
27afb09d 392 goto fail;
27afb09d
VS
393 }
394
395 return 0;
396
397 fail:
e8e5dde7
SS
398 for (; graph->filter_count > 0; graph->filter_count--)
399 avfilter_free(graph->filters[graph->filter_count - 1]);
400 av_freep(&graph->filters);
7f9b3266
SS
401 free_inout(open_inputs);
402 free_inout(open_outputs);
403 free_inout(curr_inputs);
c24f76b9 404 return ret;
27afb09d 405}