FFmpeg: libavfilter/graphparser.c Source File

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libavfilter

graphparser.c

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1 /*

2 * filter graph parser

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 GNU

16 * 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 */

23 #include <string.h>

24 #include <stdio.h>

26 #include "libavutil/avstring.h"

27 #include "libavutil/mem.h"

28 #include "avfilter.h"

30 #define WHITESPACES " \n\t"

32 /**

33 * Link two filters together.

34 *

35 * @see avfilter_link()

36 */

37 static int link_filter(AVFilterContext *src, int srcpad,

38 AVFilterContext *dst, int dstpad,

39 void *log_ctx)

40 {

41 int ret;

42 if ((ret = avfilter_link(src, srcpad, dst, dstpad))) {

43 av_log(log_ctx, AV_LOG_ERROR,

44 "Cannot create the link %s:%d -> %s:%d\n",

45 src->filter->name, srcpad, dst->filter->name, dstpad);

46 return ret;

47 }

49 return 0;

50 }

52 /**

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

57 */

58 static char *parse_link_name(const char **buf, void *log_ctx)

59 {

60 const char *start = *buf;

61 char *name;

62 (*buf)++;

64 name = av_get_token(buf, "]");

66 if (!name[0]) {

67 av_log(log_ctx, AV_LOG_ERROR,

68 "Bad (empty?) label found in the following: \"%s\".\n", start);

69 goto fail;

70 }

72 if (*(*buf)++ != ']') {

73 av_log(log_ctx, AV_LOG_ERROR,

74 "Mismatched '[' found in the following: \"%s\".\n", start);

75 fail:

76 av_freep(&name);

77 }

79 return name;

80 }

82 /**

83 * Create an instance of a filter, initialize and insert it in the

84 * filtergraph in *ctx.

85 *

86 * @param filt_ctx put here a filter context in case of successful creation and configuration, NULL otherwise.

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

92 * @return >= 0 in case of success, a negative AVERROR code otherwise

93 */

94 static int create_filter(AVFilterContext **filt_ctx, AVFilterGraph *ctx, int index,

95 const char *filt_name, const char *args, void *log_ctx)

96 {

97 AVFilter *filt;

98 char inst_name[30];

99 char *tmp_args = NULL;

100 int ret;

101

102 snprintf(inst_name, sizeof(inst_name), "Parsed_%s_%d", filt_name, index);

103

104 filt = avfilter_get_by_name(filt_name);

105

106 if (!filt) {

107 av_log(log_ctx, AV_LOG_ERROR,

108 "No such filter: '%s'\n", filt_name);

109 return AVERROR(EINVAL);

110 }

111

112 *filt_ctx = avfilter_graph_alloc_filter(ctx, filt, inst_name);

113 if (!*filt_ctx) {

114 av_log(log_ctx, AV_LOG_ERROR,

115 "Error creating filter '%s'\n", filt_name);

116 return AVERROR(ENOMEM);

117 }

118

119 if (!strcmp(filt_name, "scale") && args && !strstr(args, "flags") &&

120 ctx->scale_sws_opts) {

121 tmp_args = av_asprintf("%s:%s",

122 args, ctx->scale_sws_opts);

123 if (!tmp_args)

124 return AVERROR(ENOMEM);

125 args = tmp_args;

126 }

127

128 ret = avfilter_init_str(*filt_ctx, args);

129 if (ret < 0) {

130 av_log(log_ctx, AV_LOG_ERROR,

131 "Error initializing filter '%s'", filt_name);

132 if (args)

133 av_log(log_ctx, AV_LOG_ERROR, " with args '%s'", args);

134 av_log(log_ctx, AV_LOG_ERROR, "\n");

135 avfilter_free(*filt_ctx);

136 *filt_ctx = NULL;

137 }

138

139 av_free(tmp_args);

140 return ret;

141 }

142

143 /**

144 * Parse a string of the form FILTER_NAME[=PARAMS], and create a

145 * corresponding filter instance which is added to graph with

146 * create_filter().

147 *

148 * @param filt_ctx Pointer that is set to the created and configured filter

149 * context on success, set to NULL on failure.

150 * @param filt_ctx put here a pointer to the created filter context on

151 * success, NULL otherwise

152 * @param buf pointer to the buffer to parse, *buf will be updated to

153 * point to the char next after the parsed string

154 * @param index an index which is assigned to the created filter

155 * instance, and which is supposed to be unique for each filter

156 * instance added to the filtergraph

157 * @return >= 0 in case of success, a negative AVERROR code otherwise

158 */

159 static int parse_filter(AVFilterContext **filt_ctx, const char **buf, AVFilterGraph *graph,

160 int index, void *log_ctx)

161 {

162 char *opts = NULL;

163 char *name = av_get_token(buf, "=,;[\n");

164 int ret;

165

166 if (**buf == '=') {

167 (*buf)++;

168 opts = av_get_token(buf, "[],;\n");

169 }

170

171 ret = create_filter(filt_ctx, graph, index, name, opts, log_ctx);

172 av_free(name);

173 av_free(opts);

174 return ret;

175 }

176

177 AVFilterInOut *avfilter_inout_alloc(void)

178 {

179 return av_mallocz(sizeof(AVFilterInOut));

180 }

181

182 void avfilter_inout_free(AVFilterInOut **inout)

183 {

184 while (*inout) {

185 AVFilterInOut *next = (*inout)->next;

186 av_freep(&(*inout)->name);

187 av_freep(inout);

188 *inout = next;

189 }

190 }

191

192 static AVFilterInOut *extract_inout(const char *label, AVFilterInOut **links)

193 {

194 AVFilterInOut *ret;

195

196 while (*links && (!(*links)->name || strcmp((*links)->name, label)))

197 links = &((*links)->next);

198

199 ret = *links;

200

201 if (ret) {

202 *links = ret->next;

203 ret->next = NULL;

204 }

205

206 return ret;

207 }

208

209 static void insert_inout(AVFilterInOut **inouts, AVFilterInOut *element)

210 {

211 element->next = *inouts;

212 *inouts = element;

213 }

214

215 static void append_inout(AVFilterInOut **inouts, AVFilterInOut **element)

216 {

217 while (*inouts && (*inouts)->next)

218 inouts = &((*inouts)->next);

219

220 if (!*inouts)

221 *inouts = *element;

222 else

223 (*inouts)->next = *element;

224 *element = NULL;

225 }

226

227 static int link_filter_inouts(AVFilterContext *filt_ctx,

228 AVFilterInOut **curr_inputs,

229 AVFilterInOut **open_inputs, void *log_ctx)

230 {

231 int pad, ret;

232

233 for (pad = 0; pad < filt_ctx->nb_inputs; pad++) {

234 AVFilterInOut *p = *curr_inputs;

235

236 if (p) {

237 *curr_inputs = (*curr_inputs)->next;

238 p->next = NULL;

239 } else if (!(p = av_mallocz(sizeof(*p))))

240 return AVERROR(ENOMEM);

241

242 if (p->filter_ctx) {

243 ret = link_filter(p->filter_ctx, p->pad_idx, filt_ctx, pad, log_ctx);

244 av_free(p->name);

245 av_free(p);

246 if (ret < 0)

247 return ret;

248 } else {

249 p->filter_ctx = filt_ctx;

250 p->pad_idx = pad;

251 append_inout(open_inputs, &p);

252 }

253 }

254

255 if (*curr_inputs) {

256 av_log(log_ctx, AV_LOG_ERROR,

257 "Too many inputs specified for the \"%s\" filter.\n",

258 filt_ctx->filter->name);

259 return AVERROR(EINVAL);

260 }

261

262 pad = filt_ctx->nb_outputs;

263 while (pad--) {

264 AVFilterInOut *currlinkn = av_mallocz(sizeof(AVFilterInOut));

265 if (!currlinkn)

266 return AVERROR(ENOMEM);

267 currlinkn->filter_ctx = filt_ctx;

268 currlinkn->pad_idx = pad;

269 insert_inout(curr_inputs, currlinkn);

270 }

271

272 return 0;

273 }

274

275 static int parse_inputs(const char **buf, AVFilterInOut **curr_inputs,

276 AVFilterInOut **open_outputs, void *log_ctx)

277 {

278 AVFilterInOut *parsed_inputs = NULL;

279 int pad = 0;

280

281 while (**buf == '[') {

282 char *name = parse_link_name(buf, log_ctx);

283 AVFilterInOut *match;

284

285 if (!name)

286 return AVERROR(EINVAL);

287

288 /* First check if the label is not in the open_outputs list */

289 match = extract_inout(name, open_outputs);

290

291 if (match) {

292 av_free(name);

293 } else {

294 /* Not in the list, so add it as an input */

295 if (!(match = av_mallocz(sizeof(AVFilterInOut)))) {

296 av_free(name);

297 return AVERROR(ENOMEM);

298 }

299 match->name = name;

300 match->pad_idx = pad;

301 }

302

303 append_inout(&parsed_inputs, &match);

304

305 *buf += strspn(*buf, WHITESPACES);

306 pad++;

307 }

308

309 append_inout(&parsed_inputs, curr_inputs);

310 *curr_inputs = parsed_inputs;

311

312 return pad;

313 }

314

315 static int parse_outputs(const char **buf, AVFilterInOut **curr_inputs,

316 AVFilterInOut **open_inputs,

317 AVFilterInOut **open_outputs, void *log_ctx)

318 {

319 int ret, pad = 0;

320

321 while (**buf == '[') {

322 char *name = parse_link_name(buf, log_ctx);

323 AVFilterInOut *match;

324

325 AVFilterInOut *input = *curr_inputs;

326

327 if (!name)

328 return AVERROR(EINVAL);

329

330 if (!input) {

331 av_log(log_ctx, AV_LOG_ERROR,

332 "No output pad can be associated to link label '%s'.\n", name);

333 av_free(name);

334 return AVERROR(EINVAL);

335 }

336 *curr_inputs = (*curr_inputs)->next;

337

338 /* First check if the label is not in the open_inputs list */

339 match = extract_inout(name, open_inputs);

340

341 if (match) {

342 if ((ret = link_filter(input->filter_ctx, input->pad_idx,

343 match->filter_ctx, match->pad_idx, log_ctx)) < 0) {

344 av_free(name);

345 return ret;

346 }

347 av_free(match->name);

348 av_free(name);

349 av_free(match);

350 av_free(input);

351 } else {

352 /* Not in the list, so add the first input as a open_output */

353 input->name = name;

354 insert_inout(open_outputs, input);

355 }

356 *buf += strspn(*buf, WHITESPACES);

357 pad++;

358 }

359

360 return pad;

361 }

362

363 static int parse_sws_flags(const char **buf, AVFilterGraph *graph)

364 {

365 char *p = strchr(*buf, ';');

366

367 if (strncmp(*buf, "sws_flags=", 10))

368 return 0;

369

370 if (!p) {

371 av_log(graph, AV_LOG_ERROR, "sws_flags not terminated with ';'.\n");

372 return AVERROR(EINVAL);

373 }

374

375 *buf += 4; // keep the 'flags=' part

376

377 av_freep(&graph->scale_sws_opts);

378 if (!(graph->scale_sws_opts = av_mallocz(p - *buf + 1)))

379 return AVERROR(ENOMEM);

380 av_strlcpy(graph->scale_sws_opts, *buf, p - *buf + 1);

381

382 *buf = p + 1;

383 return 0;

384 }

385

386 int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,

387 AVFilterInOut **inputs,

388 AVFilterInOut **outputs)

389 {

390 int index = 0, ret = 0;

391 char chr = 0;

392

393 AVFilterInOut *curr_inputs = NULL, *open_inputs = NULL, *open_outputs = NULL;

394

395 filters += strspn(filters, WHITESPACES);

396

397 if ((ret = parse_sws_flags(&filters, graph)) < 0)

398 goto fail;

399

400 do {

401 AVFilterContext *filter;

402 filters += strspn(filters, WHITESPACES);

403

404 if ((ret = parse_inputs(&filters, &curr_inputs, &open_outputs, graph)) < 0)

405 goto end;

406 if ((ret = parse_filter(&filter, &filters, graph, index, graph)) < 0)

407 goto end;

408

409

410 if ((ret = link_filter_inouts(filter, &curr_inputs, &open_inputs, graph)) < 0)

411 goto end;

412

413 if ((ret = parse_outputs(&filters, &curr_inputs, &open_inputs, &open_outputs,

414 graph)) < 0)

415 goto end;

416

417 filters += strspn(filters, WHITESPACES);

418 chr = *filters++;

419

420 if (chr == ';' && curr_inputs)

421 append_inout(&open_outputs, &curr_inputs);

422 index++;

423 } while (chr == ',' || chr == ';');

424

425 if (chr) {

426 av_log(graph, AV_LOG_ERROR,

427 "Unable to parse graph description substring: \"%s\"\n",

428 filters - 1);

429 ret = AVERROR(EINVAL);

430 goto end;

431 }

432

433 append_inout(&open_outputs, &curr_inputs);

434

435

436 *inputs = open_inputs;

437 *outputs = open_outputs;

438 return 0;

439

440 fail:end:

441 while (graph->nb_filters)

442 avfilter_free(graph->filters[0]);

443 av_freep(&graph->filters);

444 avfilter_inout_free(&open_inputs);

445 avfilter_inout_free(&open_outputs);

446 avfilter_inout_free(&curr_inputs);

447

448 *inputs = NULL;

449 *outputs = NULL;

450

451 return ret;

452 }

453

454 #if HAVE_INCOMPATIBLE_LIBAV_ABI || !FF_API_OLD_GRAPH_PARSE

455 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,

456 AVFilterInOut *open_inputs,

457 AVFilterInOut *open_outputs, void *log_ctx)

458 {

459 int ret;

460 AVFilterInOut *cur, *match, *inputs = NULL, *outputs = NULL;

461

462 if ((ret = avfilter_graph_parse2(graph, filters, &inputs, &outputs)) < 0)

463 goto fail;

464

465 /* First input can be omitted if it is "[in]" */

466 if (inputs && !inputs->name)

467 inputs->name = av_strdup("in");

468 for (cur = inputs; cur; cur = cur->next) {

469 if (!cur->name) {

470 av_log(log_ctx, AV_LOG_ERROR,

471 "Not enough inputs specified for the \"%s\" filter.\n",

472 cur->filter_ctx->filter->name);

473 ret = AVERROR(EINVAL);

474 goto fail;

475 }

476 if (!(match = extract_inout(cur->name, &open_outputs)))

477 continue;

478 ret = avfilter_link(match->filter_ctx, match->pad_idx,

479 cur->filter_ctx, cur->pad_idx);

480 avfilter_inout_free(&match);

481 if (ret < 0)

482 goto fail;

483 }

484

485 /* Last output can be omitted if it is "[out]" */

486 if (outputs && !outputs->name)

487 outputs->name = av_strdup("out");

488 for (cur = outputs; cur; cur = cur->next) {

489 if (!cur->name) {

490 av_log(log_ctx, AV_LOG_ERROR,

491 "Invalid filterchain containing an unlabelled output pad: \"%s\"\n",

492 filters);

493 ret = AVERROR(EINVAL);

494 goto fail;

495 }

496 if (!(match = extract_inout(cur->name, &open_inputs)))

497 continue;

498 ret = avfilter_link(cur->filter_ctx, cur->pad_idx,

499 match->filter_ctx, match->pad_idx);

500 avfilter_inout_free(&match);

501 if (ret < 0)

502 goto fail;

503 }

504

505 fail:

506 if (ret < 0) {

507 while (graph->nb_filters)

508 avfilter_free(graph->filters[0]);

509 av_freep(&graph->filters);

510 }

511 avfilter_inout_free(&inputs);

512 avfilter_inout_free(&outputs);

513 avfilter_inout_free(&open_inputs);

514 avfilter_inout_free(&open_outputs);

515 return ret;

516 #else

517 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,

518 AVFilterInOut **inputs, AVFilterInOut **outputs,

519 void *log_ctx)

520 {

521 return avfilter_graph_parse_ptr(graph, filters, inputs, outputs, log_ctx);

522 #endif

523 }

524

525 int avfilter_graph_parse_ptr(AVFilterGraph *graph, const char *filters,

526 AVFilterInOut **open_inputs_ptr, AVFilterInOut **open_outputs_ptr,

527 void *log_ctx)

528 {

529 int index = 0, ret = 0;

530 char chr = 0;

531

532 AVFilterInOut *curr_inputs = NULL;

533 AVFilterInOut *open_inputs = open_inputs_ptr ? *open_inputs_ptr : NULL;

534 AVFilterInOut *open_outputs = open_outputs_ptr ? *open_outputs_ptr : NULL;

535

536 if ((ret = parse_sws_flags(&filters, graph)) < 0)

537 goto end;

538

539 do {

540 AVFilterContext *filter;

541 const char *filterchain = filters;

542 filters += strspn(filters, WHITESPACES);

543

544 if ((ret = parse_inputs(&filters, &curr_inputs, &open_outputs, log_ctx)) < 0)

545 goto end;

546

547 if ((ret = parse_filter(&filter, &filters, graph, index, log_ctx)) < 0)

548 goto end;

549

550 if (filter->nb_inputs == 1 && !curr_inputs && !index) {

551 /* First input pad, assume it is "[in]" if not specified */

552 const char *tmp = "[in]";

553 if ((ret = parse_inputs(&tmp, &curr_inputs, &open_outputs, log_ctx)) < 0)

554 goto end;

555 }

556

557 if ((ret = link_filter_inouts(filter, &curr_inputs, &open_inputs, log_ctx)) < 0)

558 goto end;

559

560 if ((ret = parse_outputs(&filters, &curr_inputs, &open_inputs, &open_outputs,

561 log_ctx)) < 0)

562 goto end;

563

564 filters += strspn(filters, WHITESPACES);

565 chr = *filters++;

566

567 if (chr == ';' && curr_inputs) {

568 av_log(log_ctx, AV_LOG_ERROR,

569 "Invalid filterchain containing an unlabelled output pad: \"%s\"\n",

570 filterchain);

571 ret = AVERROR(EINVAL);

572 goto end;

573 }

574 index++;

575 } while (chr == ',' || chr == ';');

576

577 if (chr) {

578 av_log(log_ctx, AV_LOG_ERROR,

579 "Unable to parse graph description substring: \"%s\"\n",

580 filters - 1);

581 ret = AVERROR(EINVAL);

582 goto end;

583 }

584

585 if (curr_inputs) {

586 /* Last output pad, assume it is "[out]" if not specified */

587 const char *tmp = "[out]";

588 if ((ret = parse_outputs(&tmp, &curr_inputs, &open_inputs, &open_outputs,

589 log_ctx)) < 0)

590 goto end;

591 }

592

593 end:

594 /* clear open_in/outputs only if not passed as parameters */

595 if (open_inputs_ptr) *open_inputs_ptr = open_inputs;

596 else avfilter_inout_free(&open_inputs);

597 if (open_outputs_ptr) *open_outputs_ptr = open_outputs;

598 else avfilter_inout_free(&open_outputs);

599 avfilter_inout_free(&curr_inputs);

600

601 if (ret < 0) {

602 while (graph->nb_filters)

603 avfilter_free(graph->filters[0]);

604 av_freep(&graph->filters);

605 }

606 return ret;

607 }

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