2 * Copyright (c) 2011 Stefano Sabatini
4 * This file is part of FFmpeg.
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.
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.
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
23 * filter for selecting which frame passes in the filterchain
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"
38 #include "libavcodec/dsputil.h"
41 static const char *const var_names[] = {
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
70 "interlace_type", ///< the frame interlace type
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
97 VAR_PREV_SELECTED_PTS,
121 VAR_INTERLACE_TYPE_P,
122 VAR_INTERLACE_TYPE_T,
123 VAR_INTERLACE_TYPE_B,
125 VAR_CONSUMED_SAMPLES_N,
141 typedef struct SelectContext {
142 const AVClass *class;
145 double var_values[VAR_VARS_NB];
146 int do_scene_detect; ///< 1 if the expression requires scene detection variables, 0 otherwise
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)
152 AVFrame *prev_picref; ///< previous frame (scene detect only)
154 int select_out; ///< mark the selected output pad index
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 }, \
168 static int request_frame(AVFilterLink *outlink);
170 static av_cold int init(AVFilterContext *ctx)
172 SelectContext *select = ctx->priv;
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",
181 select->do_scene_detect = !!strstr(select->expr_str, "scene");
183 for (i = 0; i < select->nb_outputs; i++) {
184 AVFilterPad pad = { 0 };
186 pad.name = av_asprintf("output%d", i);
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);
197 #define INTERLACE_TYPE_P 0
198 #define INTERLACE_TYPE_T 1
199 #define INTERLACE_TYPE_B 2
201 static int config_input(AVFilterLink *inlink)
203 SelectContext *select = inlink->dst->priv;
205 select->var_values[VAR_N] = 0.0;
206 select->var_values[VAR_SELECTED_N] = 0.0;
208 select->var_values[VAR_TB] = av_q2d(inlink->time_base);
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;
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;
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;
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;
240 select->var_values[VAR_SAMPLE_RATE] =
241 inlink->type == AVMEDIA_TYPE_AUDIO ? inlink->sample_rate : NAN;
244 if (select->do_scene_detect) {
245 select->avctx = avcodec_alloc_context3(NULL);
247 return AVERROR(ENOMEM);
248 avpriv_dsputil_init(&select->c, select->avctx);
255 static double get_scene_score(AVFilterContext *ctx, AVFrame *frame)
258 SelectContext *select = ctx->priv;
259 AVFrame *prev_picref = select->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;
268 uint8_t *p1 = frame->data[0];
269 uint8_t *p2 = prev_picref->data[0];
270 const int linesize = frame->linesize[0];
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](NULL, p1 + x, p2 + x,
282 mafd = nb_sad ? (double)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);
288 select->prev_picref = av_frame_clone(frame);
293 #define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
294 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
296 static void select_frame(AVFilterContext *ctx, AVFrame *frame)
298 SelectContext *select = ctx->priv;
299 AVFilterLink *inlink = ctx->inputs[0];
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);
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);
312 switch (inlink->type) {
313 case AVMEDIA_TYPE_AUDIO:
314 select->var_values[VAR_SAMPLES_N] = frame->nb_samples;
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;
323 if (select->do_scene_detect) {
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);
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]);
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]);
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]);
359 select->select_out = -1; /* drop */
360 } else if (isnan(res) || res < 0) {
361 select->select_out = 0; /* first output */
363 select->select_out = FFMIN(ceilf(res)-1, select->nb_outputs-1); /* other outputs */
366 av_log(inlink->dst, AV_LOG_DEBUG, " -> select:%f select_out:%d\n", res, select->select_out);
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;
377 select->var_values[VAR_PREV_PTS] = select->var_values[VAR_PTS];
378 select->var_values[VAR_PREV_T] = select->var_values[VAR_T];
381 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
383 AVFilterContext *ctx = inlink->dst;
384 SelectContext *select = ctx->priv;
386 select_frame(ctx, frame);
388 return ff_filter_frame(ctx->outputs[select->select_out], frame);
390 av_frame_free(&frame);
394 static int request_frame(AVFilterLink *outlink)
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);
402 int ret = ff_request_frame(inlink);
405 } while (select->select_out != out_no);
410 static av_cold void uninit(AVFilterContext *ctx)
412 SelectContext *select = ctx->priv;
415 av_expr_free(select->expr);
418 for (i = 0; i < ctx->nb_outputs; i++)
419 av_freep(&ctx->output_pads[i].name);
422 if (select->do_scene_detect) {
423 av_frame_free(&select->prev_picref);
425 avcodec_close(select->avctx);
426 av_freep(&select->avctx);
432 static int query_formats(AVFilterContext *ctx)
434 SelectContext *select = ctx->priv;
436 if (!select->do_scene_detect) {
437 return ff_default_query_formats(ctx);
439 static const enum AVPixelFormat pix_fmts[] = {
440 AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24,
443 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
448 #if CONFIG_ASELECT_FILTER
450 DEFINE_OPTIONS(aselect, AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM);
451 AVFILTER_DEFINE_CLASS(aselect);
453 static av_cold int aselect_init(AVFilterContext *ctx)
455 SelectContext *select = ctx->priv;
458 if ((ret = init(ctx)) < 0)
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);
469 static const AVFilterPad avfilter_af_aselect_inputs[] = {
472 .type = AVMEDIA_TYPE_AUDIO,
473 .config_props = config_input,
474 .filter_frame = filter_frame,
479 AVFilter ff_af_aselect = {
481 .description = NULL_IF_CONFIG_SMALL("Select audio frames to pass in output."),
482 .init = aselect_init,
484 .priv_size = sizeof(SelectContext),
485 .inputs = avfilter_af_aselect_inputs,
486 .priv_class = &aselect_class,
487 .flags = AVFILTER_FLAG_DYNAMIC_OUTPUTS,
489 #endif /* CONFIG_ASELECT_FILTER */
491 #if CONFIG_SELECT_FILTER
493 DEFINE_OPTIONS(select, AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM);
494 AVFILTER_DEFINE_CLASS(select);
496 static av_cold int select_init(AVFilterContext *ctx)
498 SelectContext *select = ctx->priv;
501 if ((ret = init(ctx)) < 0)
504 if (select->do_scene_detect && !CONFIG_AVCODEC) {
505 av_log(ctx, AV_LOG_ERROR, "Scene detection is not available without libavcodec.\n");
506 return AVERROR(EINVAL);
512 static const AVFilterPad avfilter_vf_select_inputs[] = {
515 .type = AVMEDIA_TYPE_VIDEO,
516 .config_props = config_input,
517 .filter_frame = filter_frame,
522 AVFilter ff_vf_select = {
524 .description = NULL_IF_CONFIG_SMALL("Select video frames to pass in output."),
527 .query_formats = query_formats,
528 .priv_size = sizeof(SelectContext),
529 .priv_class = &select_class,
530 .inputs = avfilter_vf_select_inputs,
531 .flags = AVFILTER_FLAG_DYNAMIC_OUTPUTS,
533 #endif /* CONFIG_SELECT_FILTER */