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1/*
2 * Copyright (c) 2011 Stefano Sabatini
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 * filter for selecting which frame passes in the filterchain
24 */
25
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 "libavutil/pixelutils.h"
32#include "avfilter.h"
33#include "audio.h"
34#include "formats.h"
35#include "internal.h"
36#include "video.h"
37
38static const char *const var_names[] = {
39 "TB", ///< timebase
40
41 "pts", ///< original pts in the file of the frame
42 "start_pts", ///< first PTS in the stream, expressed in TB units
43 "prev_pts", ///< previous frame PTS
44 "prev_selected_pts", ///< previous selected frame PTS
45
46 "t", ///< timestamp expressed in seconds
47 "start_t", ///< first PTS in the stream, expressed in seconds
48 "prev_t", ///< previous frame time
49 "prev_selected_t", ///< previously selected time
50
51 "pict_type", ///< the type of picture in the movie
52 "I",
53 "P",
54 "B",
55 "S",
56 "SI",
57 "SP",
58 "BI",
59 "PICT_TYPE_I",
60 "PICT_TYPE_P",
61 "PICT_TYPE_B",
62 "PICT_TYPE_S",
63 "PICT_TYPE_SI",
64 "PICT_TYPE_SP",
65 "PICT_TYPE_BI",
66
67 "interlace_type", ///< the frame interlace type
68 "PROGRESSIVE",
69 "TOPFIRST",
70 "BOTTOMFIRST",
71
72 "consumed_samples_n",///< number of samples consumed by the filter (only audio)
73 "samples_n", ///< number of samples in the current frame (only audio)
74 "sample_rate", ///< sample rate (only audio)
75
76 "n", ///< frame number (starting from zero)
77 "selected_n", ///< selected frame number (starting from zero)
78 "prev_selected_n", ///< number of the last selected frame
79
80 "key", ///< tell if the frame is a key frame
81 "pos", ///< original position in the file of the frame
82
83 "scene",
84
85 "concatdec_select", ///< frame is within the interval set by the concat demuxer
86
87 NULL
88};
89
90enum var_name {
91 VAR_TB,
92
93 VAR_PTS,
94 VAR_START_PTS,
95 VAR_PREV_PTS,
96 VAR_PREV_SELECTED_PTS,
97
98 VAR_T,
99 VAR_START_T,
100 VAR_PREV_T,
101 VAR_PREV_SELECTED_T,
102
103 VAR_PICT_TYPE,
104 VAR_I,
105 VAR_P,
106 VAR_B,
107 VAR_S,
108 VAR_SI,
109 VAR_SP,
110 VAR_BI,
111 VAR_PICT_TYPE_I,
112 VAR_PICT_TYPE_P,
113 VAR_PICT_TYPE_B,
114 VAR_PICT_TYPE_S,
115 VAR_PICT_TYPE_SI,
116 VAR_PICT_TYPE_SP,
117 VAR_PICT_TYPE_BI,
118
119 VAR_INTERLACE_TYPE,
120 VAR_INTERLACE_TYPE_P,
121 VAR_INTERLACE_TYPE_T,
122 VAR_INTERLACE_TYPE_B,
123
124 VAR_CONSUMED_SAMPLES_N,
125 VAR_SAMPLES_N,
126 VAR_SAMPLE_RATE,
127
128 VAR_N,
129 VAR_SELECTED_N,
130 VAR_PREV_SELECTED_N,
131
132 VAR_KEY,
133 VAR_POS,
134
135 VAR_SCENE,
136
137 VAR_CONCATDEC_SELECT,
138
139 VAR_VARS_NB
140};
141
142typedef struct SelectContext {
143 const AVClass *class;
144 char *expr_str;
145 AVExpr *expr;
146 double var_values[VAR_VARS_NB];
147 int do_scene_detect; ///< 1 if the expression requires scene detection variables, 0 otherwise
148 av_pixelutils_sad_fn sad; ///< Sum of the absolute difference function (scene detect only)
149 double prev_mafd; ///< previous MAFD (scene detect only)
150 AVFrame *prev_picref; ///< previous frame (scene detect only)
151 double select;
152 int select_out; ///< mark the selected output pad index
153 int nb_outputs;
154} SelectContext;
155
156#define OFFSET(x) offsetof(SelectContext, x)
157#define DEFINE_OPTIONS(filt_name, FLAGS) \
158static const AVOption filt_name##_options[] = { \
159 { "expr", "set an expression to use for selecting frames", OFFSET(expr_str), AV_OPT_TYPE_STRING, { .str = "1" }, .flags=FLAGS }, \
160 { "e", "set an expression to use for selecting frames", OFFSET(expr_str), AV_OPT_TYPE_STRING, { .str = "1" }, .flags=FLAGS }, \
161 { "outputs", "set the number of outputs", OFFSET(nb_outputs), AV_OPT_TYPE_INT, {.i64 = 1}, 1, INT_MAX, .flags=FLAGS }, \
162 { "n", "set the number of outputs", OFFSET(nb_outputs), AV_OPT_TYPE_INT, {.i64 = 1}, 1, INT_MAX, .flags=FLAGS }, \
163 { NULL } \
164}
165
166static int request_frame(AVFilterLink *outlink);
167
168static av_cold int init(AVFilterContext *ctx)
169{
170 SelectContext *select = ctx->priv;
171 int i, ret;
172
173 if ((ret = av_expr_parse(&select->expr, select->expr_str,
174 var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
175 av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n",
176 select->expr_str);
177 return ret;
178 }
179 select->do_scene_detect = !!strstr(select->expr_str, "scene");
180
181 for (i = 0; i < select->nb_outputs; i++) {
182 AVFilterPad pad = { 0 };
183
184 pad.name = av_asprintf("output%d", i);
185 if (!pad.name)
186 return AVERROR(ENOMEM);
187 pad.type = ctx->filter->inputs[0].type;
188 pad.request_frame = request_frame;
189 ff_insert_outpad(ctx, i, &pad);
190 }
191
192 return 0;
193}
194
195#define INTERLACE_TYPE_P 0
196#define INTERLACE_TYPE_T 1
197#define INTERLACE_TYPE_B 2
198
199static int config_input(AVFilterLink *inlink)
200{
201 SelectContext *select = inlink->dst->priv;
202
203 select->var_values[VAR_N] = 0.0;
204 select->var_values[VAR_SELECTED_N] = 0.0;
205
206 select->var_values[VAR_TB] = av_q2d(inlink->time_base);
207
208 select->var_values[VAR_PREV_PTS] = NAN;
209 select->var_values[VAR_PREV_SELECTED_PTS] = NAN;
210 select->var_values[VAR_PREV_SELECTED_T] = NAN;
211 select->var_values[VAR_PREV_T] = NAN;
212 select->var_values[VAR_START_PTS] = NAN;
213 select->var_values[VAR_START_T] = NAN;
214
215 select->var_values[VAR_I] = AV_PICTURE_TYPE_I;
216 select->var_values[VAR_P] = AV_PICTURE_TYPE_P;
217 select->var_values[VAR_B] = AV_PICTURE_TYPE_B;
218 select->var_values[VAR_SI] = AV_PICTURE_TYPE_SI;
219 select->var_values[VAR_SP] = AV_PICTURE_TYPE_SP;
220 select->var_values[VAR_BI] = AV_PICTURE_TYPE_BI;
221 select->var_values[VAR_PICT_TYPE_I] = AV_PICTURE_TYPE_I;
222 select->var_values[VAR_PICT_TYPE_P] = AV_PICTURE_TYPE_P;
223 select->var_values[VAR_PICT_TYPE_B] = AV_PICTURE_TYPE_B;
224 select->var_values[VAR_PICT_TYPE_SI] = AV_PICTURE_TYPE_SI;
225 select->var_values[VAR_PICT_TYPE_SP] = AV_PICTURE_TYPE_SP;
226 select->var_values[VAR_PICT_TYPE_BI] = AV_PICTURE_TYPE_BI;
227
228 select->var_values[VAR_INTERLACE_TYPE_P] = INTERLACE_TYPE_P;
229 select->var_values[VAR_INTERLACE_TYPE_T] = INTERLACE_TYPE_T;
230 select->var_values[VAR_INTERLACE_TYPE_B] = INTERLACE_TYPE_B;
231
232 select->var_values[VAR_PICT_TYPE] = NAN;
233 select->var_values[VAR_INTERLACE_TYPE] = NAN;
234 select->var_values[VAR_SCENE] = NAN;
235 select->var_values[VAR_CONSUMED_SAMPLES_N] = NAN;
236 select->var_values[VAR_SAMPLES_N] = NAN;
237
238 select->var_values[VAR_SAMPLE_RATE] =
239 inlink->type == AVMEDIA_TYPE_AUDIO ? inlink->sample_rate : NAN;
240
241 if (select->do_scene_detect) {
242 select->sad = av_pixelutils_get_sad_fn(3, 3, 2, select); // 8x8 both sources aligned
243 if (!select->sad)
244 return AVERROR(EINVAL);
245 }
246 return 0;
247}
248
249static double get_scene_score(AVFilterContext *ctx, AVFrame *frame)
250{
251 double ret = 0;
252 SelectContext *select = ctx->priv;
253 AVFrame *prev_picref = select->prev_picref;
254
255 if (prev_picref &&
256 frame->height == prev_picref->height &&
257 frame->width == prev_picref->width) {
258 int x, y, nb_sad = 0;
259 int64_t sad = 0;
260 double mafd, diff;
261 uint8_t *p1 = frame->data[0];
262 uint8_t *p2 = prev_picref->data[0];
263 const int p1_linesize = frame->linesize[0];
264 const int p2_linesize = prev_picref->linesize[0];
265
266 for (y = 0; y < frame->height - 7; y += 8) {
267 for (x = 0; x < frame->width*3 - 7; x += 8) {
268 sad += select->sad(p1 + x, p1_linesize, p2 + x, p2_linesize);
269 nb_sad += 8 * 8;
270 }
271 p1 += 8 * p1_linesize;
272 p2 += 8 * p2_linesize;
273 }
274 emms_c();
275 mafd = nb_sad ? (double)sad / nb_sad : 0;
276 diff = fabs(mafd - select->prev_mafd);
277 ret = av_clipf(FFMIN(mafd, diff) / 100., 0, 1);
278 select->prev_mafd = mafd;
279 av_frame_free(&prev_picref);
280 }
281 select->prev_picref = av_frame_clone(frame);
282 return ret;
283}
284
285static double get_concatdec_select(AVFrame *frame, int64_t pts)
286{
287 AVDictionary *metadata = av_frame_get_metadata(frame);
288 AVDictionaryEntry *start_time_entry = av_dict_get(metadata, "lavf.concatdec.start_time", NULL, 0);
289 AVDictionaryEntry *duration_entry = av_dict_get(metadata, "lavf.concatdec.duration", NULL, 0);
290 if (start_time_entry) {
291 int64_t start_time = strtoll(start_time_entry->value, NULL, 10);
292 if (pts >= start_time) {
293 if (duration_entry) {
294 int64_t duration = strtoll(duration_entry->value, NULL, 10);
295 if (pts < start_time + duration)
296 return -1;
297 else
298 return 0;
299 }
300 return -1;
301 }
302 return 0;
303 }
304 return NAN;
305}
306
307#define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
308#define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
309
310static void select_frame(AVFilterContext *ctx, AVFrame *frame)
311{
312 SelectContext *select = ctx->priv;
313 AVFilterLink *inlink = ctx->inputs[0];
314 double res;
315
316 if (isnan(select->var_values[VAR_START_PTS]))
317 select->var_values[VAR_START_PTS] = TS2D(frame->pts);
318 if (isnan(select->var_values[VAR_START_T]))
319 select->var_values[VAR_START_T] = TS2D(frame->pts) * av_q2d(inlink->time_base);
320
321 select->var_values[VAR_N ] = inlink->frame_count_out;
322 select->var_values[VAR_PTS] = TS2D(frame->pts);
323 select->var_values[VAR_T ] = TS2D(frame->pts) * av_q2d(inlink->time_base);
324 select->var_values[VAR_POS] = av_frame_get_pkt_pos(frame) == -1 ? NAN : av_frame_get_pkt_pos(frame);
325 select->var_values[VAR_KEY] = frame->key_frame;
326 select->var_values[VAR_CONCATDEC_SELECT] = get_concatdec_select(frame, av_rescale_q(frame->pts, inlink->time_base, AV_TIME_BASE_Q));
327
328 switch (inlink->type) {
329 case AVMEDIA_TYPE_AUDIO:
330 select->var_values[VAR_SAMPLES_N] = frame->nb_samples;
331 break;
332
333 case AVMEDIA_TYPE_VIDEO:
334 select->var_values[VAR_INTERLACE_TYPE] =
335 !frame->interlaced_frame ? INTERLACE_TYPE_P :
336 frame->top_field_first ? INTERLACE_TYPE_T : INTERLACE_TYPE_B;
337 select->var_values[VAR_PICT_TYPE] = frame->pict_type;
338 if (select->do_scene_detect) {
339 char buf[32];
340 select->var_values[VAR_SCENE] = get_scene_score(ctx, frame);
341 // TODO: document metadata
342 snprintf(buf, sizeof(buf), "%f", select->var_values[VAR_SCENE]);
343 av_dict_set(avpriv_frame_get_metadatap(frame), "lavfi.scene_score", buf, 0);
344 }
345 break;
346 }
347
348 select->select = res = av_expr_eval(select->expr, select->var_values, NULL);
349 av_log(inlink->dst, AV_LOG_DEBUG,
350 "n:%f pts:%f t:%f key:%d",
351 select->var_values[VAR_N],
352 select->var_values[VAR_PTS],
353 select->var_values[VAR_T],
354 frame->key_frame);
355
356 switch (inlink->type) {
357 case AVMEDIA_TYPE_VIDEO:
358 av_log(inlink->dst, AV_LOG_DEBUG, " interlace_type:%c pict_type:%c scene:%f",
359 (!frame->interlaced_frame) ? 'P' :
360 frame->top_field_first ? 'T' : 'B',
361 av_get_picture_type_char(frame->pict_type),
362 select->var_values[VAR_SCENE]);
363 break;
364 case AVMEDIA_TYPE_AUDIO:
365 av_log(inlink->dst, AV_LOG_DEBUG, " samples_n:%d consumed_samples_n:%f",
366 frame->nb_samples,
367 select->var_values[VAR_CONSUMED_SAMPLES_N]);
368 break;
369 }
370
371 if (res == 0) {
372 select->select_out = -1; /* drop */
373 } else if (isnan(res) || res < 0) {
374 select->select_out = 0; /* first output */
375 } else {
376 select->select_out = FFMIN(ceilf(res)-1, select->nb_outputs-1); /* other outputs */
377 }
378
379 av_log(inlink->dst, AV_LOG_DEBUG, " -> select:%f select_out:%d\n", res, select->select_out);
380
381 if (res) {
382 select->var_values[VAR_PREV_SELECTED_N] = select->var_values[VAR_N];
383 select->var_values[VAR_PREV_SELECTED_PTS] = select->var_values[VAR_PTS];
384 select->var_values[VAR_PREV_SELECTED_T] = select->var_values[VAR_T];
385 select->var_values[VAR_SELECTED_N] += 1.0;
386 if (inlink->type == AVMEDIA_TYPE_AUDIO)
387 select->var_values[VAR_CONSUMED_SAMPLES_N] += frame->nb_samples;
388 }
389
390 select->var_values[VAR_PREV_PTS] = select->var_values[VAR_PTS];
391 select->var_values[VAR_PREV_T] = select->var_values[VAR_T];
392}
393
394static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
395{
396 AVFilterContext *ctx = inlink->dst;
397 SelectContext *select = ctx->priv;
398
399 select_frame(ctx, frame);
400 if (select->select)
401 return ff_filter_frame(ctx->outputs[select->select_out], frame);
402
403 av_frame_free(&frame);
404 return 0;
405}
406
407static int request_frame(AVFilterLink *outlink)
408{
409 AVFilterLink *inlink = outlink->src->inputs[0];
410 int ret = ff_request_frame(inlink);
411 return ret;
412}
413
414static av_cold void uninit(AVFilterContext *ctx)
415{
416 SelectContext *select = ctx->priv;
417 int i;
418
419 av_expr_free(select->expr);
420 select->expr = NULL;
421
422 for (i = 0; i < ctx->nb_outputs; i++)
423 av_freep(&ctx->output_pads[i].name);
424
425 if (select->do_scene_detect) {
426 av_frame_free(&select->prev_picref);
427 }
428}
429
430static int query_formats(AVFilterContext *ctx)
431{
432 SelectContext *select = ctx->priv;
433
434 if (!select->do_scene_detect) {
435 return ff_default_query_formats(ctx);
436 } else {
437 int ret;
438 static const enum AVPixelFormat pix_fmts[] = {
439 AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24,
440 AV_PIX_FMT_NONE
441 };
442 AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
443
444 if (!fmts_list)
445 return AVERROR(ENOMEM);
446 ret = ff_set_common_formats(ctx, fmts_list);
447 if (ret < 0)
448 return ret;
449 }
450 return 0;
451}
452
453#if CONFIG_ASELECT_FILTER
454
455DEFINE_OPTIONS(aselect, AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM);
456AVFILTER_DEFINE_CLASS(aselect);
457
458static av_cold int aselect_init(AVFilterContext *ctx)
459{
460 SelectContext *select = ctx->priv;
461 int ret;
462
463 if ((ret = init(ctx)) < 0)
464 return ret;
465
466 if (select->do_scene_detect) {
467 av_log(ctx, AV_LOG_ERROR, "Scene detection is ignored in aselect filter\n");
468 return AVERROR(EINVAL);
469 }
470
471 return 0;
472}
473
474static const AVFilterPad avfilter_af_aselect_inputs[] = {
475 {
476 .name = "default",
477 .type = AVMEDIA_TYPE_AUDIO,
478 .config_props = config_input,
479 .filter_frame = filter_frame,
480 },
481 { NULL }
482};
483
484AVFilter ff_af_aselect = {
485 .name = "aselect",
486 .description = NULL_IF_CONFIG_SMALL("Select audio frames to pass in output."),
487 .init = aselect_init,
488 .uninit = uninit,
489 .priv_size = sizeof(SelectContext),
490 .inputs = avfilter_af_aselect_inputs,
491 .priv_class = &aselect_class,
492 .flags = AVFILTER_FLAG_DYNAMIC_OUTPUTS,
493};
494#endif /* CONFIG_ASELECT_FILTER */
495
496#if CONFIG_SELECT_FILTER
497
498DEFINE_OPTIONS(select, AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM);
499AVFILTER_DEFINE_CLASS(select);
500
501static av_cold int select_init(AVFilterContext *ctx)
502{
503 int ret;
504
505 if ((ret = init(ctx)) < 0)
506 return ret;
507
508 return 0;
509}
510
511static const AVFilterPad avfilter_vf_select_inputs[] = {
512 {
513 .name = "default",
514 .type = AVMEDIA_TYPE_VIDEO,
515 .config_props = config_input,
516 .filter_frame = filter_frame,
517 },
518 { NULL }
519};
520
521AVFilter ff_vf_select = {
522 .name = "select",
523 .description = NULL_IF_CONFIG_SMALL("Select video frames to pass in output."),
524 .init = select_init,
525 .uninit = uninit,
526 .query_formats = query_formats,
527 .priv_size = sizeof(SelectContext),
528 .priv_class = &select_class,
529 .inputs = avfilter_vf_select_inputs,
530 .flags = AVFILTER_FLAG_DYNAMIC_OUTPUTS,
531};
532#endif /* CONFIG_SELECT_FILTER */
533
generated by cgit at 2024-05-17 05:04:54 (GMT)