FFmpeg: libavfilter/f_select.c Source File

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libavfilter

f_select.c

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1 /*

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 */

21 /**

22 * @file

23 * filter for selecting which frame passes in the filterchain

24 */

26 #include "libavutil/avstring.h"

27 #include "libavutil/eval.h"

28 #include "libavutil/fifo.h"

29 #include "libavutil/internal.h"

30 #include "libavutil/opt.h"

31 #include "avfilter.h"

32 #include "audio.h"

33 #include "formats.h"

34 #include "internal.h"

35 #include "video.h"

37 #if CONFIG_AVCODEC

38 #include "libavcodec/dsputil.h"

39 #endif

41 static const char *const var_names[] = {

42 "TB", ///< timebase

44 "pts", ///< original pts in the file of the frame

45 "start_pts", ///< first PTS in the stream, expressed in TB units

46 "prev_pts", ///< previous frame PTS

47 "prev_selected_pts", ///< previous selected frame PTS

49 "t", ///< first PTS in seconds

50 "start_t", ///< first PTS in the stream, expressed in seconds

51 "prev_t", ///< previous frame time

52 "prev_selected_t", ///< previously selected time

54 "pict_type", ///< the type of picture in the movie

55 "I",

56 "P",

57 "B",

58 "S",

59 "SI",

60 "SP",

61 "BI",

62 "PICT_TYPE_I",

63 "PICT_TYPE_P",

64 "PICT_TYPE_B",

65 "PICT_TYPE_S",

66 "PICT_TYPE_SI",

67 "PICT_TYPE_SP",

68 "PICT_TYPE_BI",

70 "interlace_type", ///< the frame interlace type

71 "PROGRESSIVE",

72 "TOPFIRST",

73 "BOTTOMFIRST",

75 "consumed_samples_n",///< number of samples consumed by the filter (only audio)

76 "samples_n", ///< number of samples in the current frame (only audio)

77 "sample_rate", ///< sample rate (only audio)

79 "n", ///< frame number (starting from zero)

80 "selected_n", ///< selected frame number (starting from zero)

81 "prev_selected_n", ///< number of the last selected frame

83 "key", ///< tell if the frame is a key frame

84 "pos", ///< original position in the file of the frame

86 "scene",

88 NULL

89 };

91 enum var_name {

92 VAR_TB,

94 VAR_PTS,

95 VAR_START_PTS,

96 VAR_PREV_PTS,

97 VAR_PREV_SELECTED_PTS,

99 VAR_T,

100 VAR_START_T,

101 VAR_PREV_T,

102 VAR_PREV_SELECTED_T,

103

104 VAR_PICT_TYPE,

105 VAR_I,

106 VAR_P,

107 VAR_B,

108 VAR_S,

109 VAR_SI,

110 VAR_SP,

111 VAR_BI,

112 VAR_PICT_TYPE_I,

113 VAR_PICT_TYPE_P,

114 VAR_PICT_TYPE_B,

115 VAR_PICT_TYPE_S,

116 VAR_PICT_TYPE_SI,

117 VAR_PICT_TYPE_SP,

118 VAR_PICT_TYPE_BI,

119

120 VAR_INTERLACE_TYPE,

121 VAR_INTERLACE_TYPE_P,

122 VAR_INTERLACE_TYPE_T,

123 VAR_INTERLACE_TYPE_B,

124

125 VAR_CONSUMED_SAMPLES_N,

126 VAR_SAMPLES_N,

127 VAR_SAMPLE_RATE,

128

129 VAR_N,

130 VAR_SELECTED_N,

131 VAR_PREV_SELECTED_N,

132

133 VAR_KEY,

134 VAR_POS,

135

136 VAR_SCENE,

137

138 VAR_VARS_NB

139 };

140

141 typedef struct {

142 const AVClass *class;

143 char *expr_str;

144 AVExpr *expr;

145 double var_values[VAR_VARS_NB];

146 int do_scene_detect; ///< 1 if the expression requires scene detection variables, 0 otherwise

147 #if CONFIG_AVCODEC

148 AVCodecContext *avctx; ///< codec context required for the DSPContext (scene detect only)

149 DSPContext c; ///< context providing optimized SAD methods (scene detect only)

150 double prev_mafd; ///< previous MAFD (scene detect only)

151 #endif

152 AVFrame *prev_picref; ///< previous frame (scene detect only)

153 double select;

154 int select_out; ///< mark the selected output pad index

155 int nb_outputs;

156 } SelectContext;

157

158 #define OFFSET(x) offsetof(SelectContext, x)

159 #define DEFINE_OPTIONS(filt_name, FLAGS) \

160 static const AVOption filt_name##_options[] = { \

161 { "expr", "set an expression to use for selecting frames", OFFSET(expr_str), AV_OPT_TYPE_STRING, { .str = "1" }, .flags=FLAGS }, \

162 { "e", "set an expression to use for selecting frames", OFFSET(expr_str), AV_OPT_TYPE_STRING, { .str = "1" }, .flags=FLAGS }, \

163 { "outputs", "set the number of outputs", OFFSET(nb_outputs), AV_OPT_TYPE_INT, {.i64 = 1}, 1, INT_MAX, .flags=FLAGS }, \

164 { "n", "set the number of outputs", OFFSET(nb_outputs), AV_OPT_TYPE_INT, {.i64 = 1}, 1, INT_MAX, .flags=FLAGS }, \

165 { NULL } \

166 }

167

168 static int request_frame(AVFilterLink *outlink);

169

170 static av_cold int init(AVFilterContext *ctx)

171 {

172 SelectContext *select = ctx->priv;

173 int i, ret;

174

175 if ((ret = av_expr_parse(&select->expr, select->expr_str,

176 var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {

177 av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n",

178 select->expr_str);

179 return ret;

180 }

181 select->do_scene_detect = !!strstr(select->expr_str, "scene");

182

183 for (i = 0; i < select->nb_outputs; i++) {

184 AVFilterPad pad = { 0 };

185

186 pad.name = av_asprintf("output%d", i);

187 if (!pad.name)

188 return AVERROR(ENOMEM);

189 pad.type = ctx->filter->inputs[0].type;

190 pad.request_frame = request_frame;

191 ff_insert_outpad(ctx, i, &pad);

192 }

193

194 return 0;

195 }

196

197 #define INTERLACE_TYPE_P 0

198 #define INTERLACE_TYPE_T 1

199 #define INTERLACE_TYPE_B 2

200

201 static int config_input(AVFilterLink *inlink)

202 {

203 SelectContext *select = inlink->dst->priv;

204

205 select->var_values[VAR_N] = 0.0;

206 select->var_values[VAR_SELECTED_N] = 0.0;

207

208 select->var_values[VAR_TB] = av_q2d(inlink->time_base);

209

210 select->var_values[VAR_PREV_PTS] = NAN;

211 select->var_values[VAR_PREV_SELECTED_PTS] = NAN;

212 select->var_values[VAR_PREV_SELECTED_T] = NAN;

213 select->var_values[VAR_PREV_T] = NAN;

214 select->var_values[VAR_START_PTS] = NAN;

215 select->var_values[VAR_START_T] = NAN;

216

217 select->var_values[VAR_I] = AV_PICTURE_TYPE_I;

218 select->var_values[VAR_P] = AV_PICTURE_TYPE_P;

219 select->var_values[VAR_B] = AV_PICTURE_TYPE_B;

220 select->var_values[VAR_SI] = AV_PICTURE_TYPE_SI;

221 select->var_values[VAR_SP] = AV_PICTURE_TYPE_SP;

222 select->var_values[VAR_BI] = AV_PICTURE_TYPE_BI;

223 select->var_values[VAR_PICT_TYPE_I] = AV_PICTURE_TYPE_I;

224 select->var_values[VAR_PICT_TYPE_P] = AV_PICTURE_TYPE_P;

225 select->var_values[VAR_PICT_TYPE_B] = AV_PICTURE_TYPE_B;

226 select->var_values[VAR_PICT_TYPE_SI] = AV_PICTURE_TYPE_SI;

227 select->var_values[VAR_PICT_TYPE_SP] = AV_PICTURE_TYPE_SP;

228 select->var_values[VAR_PICT_TYPE_BI] = AV_PICTURE_TYPE_BI;

229

230 select->var_values[VAR_INTERLACE_TYPE_P] = INTERLACE_TYPE_P;

231 select->var_values[VAR_INTERLACE_TYPE_T] = INTERLACE_TYPE_T;

232 select->var_values[VAR_INTERLACE_TYPE_B] = INTERLACE_TYPE_B;

233

234 select->var_values[VAR_PICT_TYPE] = NAN;

235 select->var_values[VAR_INTERLACE_TYPE] = NAN;

236 select->var_values[VAR_SCENE] = NAN;

237 select->var_values[VAR_CONSUMED_SAMPLES_N] = NAN;

238 select->var_values[VAR_SAMPLES_N] = NAN;

239

240 select->var_values[VAR_SAMPLE_RATE] =

241 inlink->type == AVMEDIA_TYPE_AUDIO ? inlink->sample_rate : NAN;

242

243 #if CONFIG_AVCODEC

244 if (select->do_scene_detect) {

245 select->avctx = avcodec_alloc_context3(NULL);

246 if (!select->avctx)

247 return AVERROR(ENOMEM);

248 avpriv_dsputil_init(&select->c, select->avctx);

249 }

250 #endif

251 return 0;

252 }

253

254 #if CONFIG_AVCODEC

255 static double get_scene_score(AVFilterContext *ctx, AVFrame *frame)

256 {

257 double ret = 0;

258 SelectContext *select = ctx->priv;

259 AVFrame *prev_picref = select->prev_picref;

260

261 if (prev_picref &&

262 frame->height == prev_picref->height &&

263 frame->width == prev_picref->width &&

264 frame->linesize[0] == prev_picref->linesize[0]) {

265 int x, y, nb_sad = 0;

266 int64_t sad = 0;

267 double mafd, diff;

268 uint8_t *p1 = frame->data[0];

269 uint8_t *p2 = prev_picref->data[0];

270 const int linesize = frame->linesize[0];

271

272 for (y = 0; y < frame->height - 8; y += 8) {

273 for (x = 0; x < frame->width*3 - 8; x += 8) {

274 sad += select->c.sad[1](select, p1 + x, p2 + x,

275 linesize, 8);

276 nb_sad += 8 * 8;

277 }

278 p1 += 8 * linesize;

279 p2 += 8 * linesize;

280 }

281 emms_c();

282 mafd = nb_sad ? sad / nb_sad : 0;

283 diff = fabs(mafd - select->prev_mafd);

284 ret = av_clipf(FFMIN(mafd, diff) / 100., 0, 1);

285 select->prev_mafd = mafd;

286 av_frame_free(&prev_picref);

287 }

288 select->prev_picref = av_frame_clone(frame);

289 return ret;

290 }

291 #endif

292

293 #define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))

294 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))

295

296 static void select_frame(AVFilterContext *ctx, AVFrame *frame)

297 {

298 SelectContext *select = ctx->priv;

299 AVFilterLink *inlink = ctx->inputs[0];

300 double res;

301

302 if (isnan(select->var_values[VAR_START_PTS]))

303 select->var_values[VAR_START_PTS] = TS2D(frame->pts);

304 if (isnan(select->var_values[VAR_START_T]))

305 select->var_values[VAR_START_T] = TS2D(frame->pts) * av_q2d(inlink->time_base);

306

307 select->var_values[VAR_N ] = inlink->frame_count;

308 select->var_values[VAR_PTS] = TS2D(frame->pts);

309 select->var_values[VAR_T ] = TS2D(frame->pts) * av_q2d(inlink->time_base);

310 select->var_values[VAR_POS] = av_frame_get_pkt_pos(frame) == -1 ? NAN : av_frame_get_pkt_pos(frame);

311

312 switch (inlink->type) {

313 case AVMEDIA_TYPE_AUDIO:

314 select->var_values[VAR_SAMPLES_N] = frame->nb_samples;

315 break;

316

317 case AVMEDIA_TYPE_VIDEO:

318 select->var_values[VAR_INTERLACE_TYPE] =

319 !frame->interlaced_frame ? INTERLACE_TYPE_P :

320 frame->top_field_first ? INTERLACE_TYPE_T : INTERLACE_TYPE_B;

321 select->var_values[VAR_PICT_TYPE] = frame->pict_type;

322 #if CONFIG_AVCODEC

323 if (select->do_scene_detect) {

324 char buf[32];

325 select->var_values[VAR_SCENE] = get_scene_score(ctx, frame);

326 // TODO: document metadata

327 snprintf(buf, sizeof(buf), "%f", select->var_values[VAR_SCENE]);

328 av_dict_set(avpriv_frame_get_metadatap(frame), "lavfi.scene_score", buf, 0);

329 }

330 #endif

331 break;

332 }

333

334 select->select = res = av_expr_eval(select->expr, select->var_values, NULL);

335 av_log(inlink->dst, AV_LOG_DEBUG,

336 "n:%f pts:%f t:%f key:%d",

337 select->var_values[VAR_N],

338 select->var_values[VAR_PTS],

339 select->var_values[VAR_T],

340 (int)select->var_values[VAR_KEY]);

341

342 switch (inlink->type) {

343 case AVMEDIA_TYPE_VIDEO:

344 av_log(inlink->dst, AV_LOG_DEBUG, " interlace_type:%c pict_type:%c scene:%f",

345 select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_P ? 'P' :

346 select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_T ? 'T' :

347 select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_B ? 'B' : '?',

348 av_get_picture_type_char(select->var_values[VAR_PICT_TYPE]),

349 select->var_values[VAR_SCENE]);

350 break;

351 case AVMEDIA_TYPE_AUDIO:

352 av_log(inlink->dst, AV_LOG_DEBUG, " samples_n:%d consumed_samples_n:%d",

353 (int)select->var_values[VAR_SAMPLES_N],

354 (int)select->var_values[VAR_CONSUMED_SAMPLES_N]);

355 break;

356 }

357

358 if (res == 0) {

359 select->select_out = -1; /* drop */

360 } else if (isnan(res) || res < 0) {

361 select->select_out = 0; /* first output */

362 } else {

363 select->select_out = FFMIN(ceilf(res)-1, select->nb_outputs-1); /* other outputs */

364 }

365

366 av_log(inlink->dst, AV_LOG_DEBUG, " -> select:%f select_out:%d\n", res, select->select_out);

367

368 if (res) {

369 select->var_values[VAR_PREV_SELECTED_N] = select->var_values[VAR_N];

370 select->var_values[VAR_PREV_SELECTED_PTS] = select->var_values[VAR_PTS];

371 select->var_values[VAR_PREV_SELECTED_T] = select->var_values[VAR_T];

372 select->var_values[VAR_SELECTED_N] += 1.0;

373 if (inlink->type == AVMEDIA_TYPE_AUDIO)

374 select->var_values[VAR_CONSUMED_SAMPLES_N] += frame->nb_samples;

375 }

376

377 select->var_values[VAR_PREV_PTS] = select->var_values[VAR_PTS];

378 select->var_values[VAR_PREV_T] = select->var_values[VAR_T];

379 }

380

381 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)

382 {

383 AVFilterContext *ctx = inlink->dst;

384 SelectContext *select = ctx->priv;

385

386 select_frame(ctx, frame);

387 if (select->select)

388 return ff_filter_frame(ctx->outputs[select->select_out], frame);

389

390 av_frame_free(&frame);

391 return 0;

392 }

393

394 static int request_frame(AVFilterLink *outlink)

395 {

396 AVFilterContext *ctx = outlink->src;

397 SelectContext *select = ctx->priv;

398 AVFilterLink *inlink = outlink->src->inputs[0];

399 int out_no = FF_OUTLINK_IDX(outlink);

400

401 do {

402 int ret = ff_request_frame(inlink);

403 if (ret < 0)

404 return ret;

405 } while (select->select_out != out_no);

406

407 return 0;

408 }

409

410 static av_cold void uninit(AVFilterContext *ctx)

411 {

412 SelectContext *select = ctx->priv;

413 int i;

414

415 av_expr_free(select->expr);

416 select->expr = NULL;

417

418 for (i = 0; i < ctx->nb_outputs; i++)

419 av_freep(&ctx->output_pads[i].name);

420

421 #if CONFIG_AVCODEC

422 if (select->do_scene_detect) {

423 av_frame_free(&select->prev_picref);

424 if (select->avctx) {

425 avcodec_close(select->avctx);

426 av_freep(&select->avctx);

427 }

428 }

429 #endif

430 }

431

432 static int query_formats(AVFilterContext *ctx)

433 {

434 SelectContext *select = ctx->priv;

435

436 if (!select->do_scene_detect) {

437 return ff_default_query_formats(ctx);

438 } else {

439 static const enum AVPixelFormat pix_fmts[] = {

440 AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24,

441 AV_PIX_FMT_NONE

442 };

443 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));

444 }

445 return 0;

446 }

447

448 #if CONFIG_ASELECT_FILTER

449

450 DEFINE_OPTIONS(aselect, AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM);

451 AVFILTER_DEFINE_CLASS(aselect);

452

453 static av_cold int aselect_init(AVFilterContext *ctx)

454 {

455 SelectContext *select = ctx->priv;

456 int ret;

457

458 if ((ret = init(ctx)) < 0)

459 return ret;

460

461 if (select->do_scene_detect) {

462 av_log(ctx, AV_LOG_ERROR, "Scene detection is ignored in aselect filter\n");

463 return AVERROR(EINVAL);

464 }

465

466 return 0;

467 }

468

469 static const AVFilterPad avfilter_af_aselect_inputs[] = {

470 {

471 .name = "default",

472 .type = AVMEDIA_TYPE_AUDIO,

473 .get_audio_buffer = ff_null_get_audio_buffer,

474 .config_props = config_input,

475 .filter_frame = filter_frame,

476 },

477 { NULL }

478 };

479

480 AVFilter avfilter_af_aselect = {

481 .name = "aselect",

482 .description = NULL_IF_CONFIG_SMALL("Select audio frames to pass in output."),

483 .init = aselect_init,

484 .uninit = uninit,

485 .priv_size = sizeof(SelectContext),

486 .inputs = avfilter_af_aselect_inputs,

487 .priv_class = &aselect_class,

488 .flags = AVFILTER_FLAG_DYNAMIC_OUTPUTS,

489 };

490 #endif /* CONFIG_ASELECT_FILTER */

491

492 #if CONFIG_SELECT_FILTER

493

494 DEFINE_OPTIONS(select, AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM);

495 AVFILTER_DEFINE_CLASS(select);

496

497 static av_cold int select_init(AVFilterContext *ctx)

498 {

499 SelectContext *select = ctx->priv;

500 int ret;

501

502 if ((ret = init(ctx)) < 0)

503 return ret;

504

505 if (select->do_scene_detect && !CONFIG_AVCODEC) {

506 av_log(ctx, AV_LOG_ERROR, "Scene detection is not available without libavcodec.\n");

507 return AVERROR(EINVAL);

508 }

509

510 return 0;

511 }

512

513 static const AVFilterPad avfilter_vf_select_inputs[] = {

514 {

515 .name = "default",

516 .type = AVMEDIA_TYPE_VIDEO,

517 .get_video_buffer = ff_null_get_video_buffer,

518 .config_props = config_input,

519 .filter_frame = filter_frame,

520 },

521 { NULL }

522 };

523

524 AVFilter avfilter_vf_select = {

525 .name = "select",

526 .description = NULL_IF_CONFIG_SMALL("Select video frames to pass in output."),

527 .init = select_init,

528 .uninit = uninit,

529 .query_formats = query_formats,

530

531 .priv_size = sizeof(SelectContext),

532 .priv_class = &select_class,

533

534 .inputs = avfilter_vf_select_inputs,

535 .flags = AVFILTER_FLAG_DYNAMIC_OUTPUTS,

536 };

537 #endif /* CONFIG_SELECT_FILTER */

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