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/eval.h"
27 #include "libavutil/fifo.h"
28 #include "libavcodec/dsputil.h"
34 static const char *const var_names[] = {
37 "pts", ///< original pts in the file of the frame
38 "start_pts", ///< first PTS in the stream, expressed in TB units
39 "prev_pts", ///< previous frame PTS
40 "prev_selected_pts", ///< previous selected frame PTS
42 "t", ///< first PTS in seconds
43 "start_t", ///< first PTS in the stream, expressed in seconds
44 "prev_t", ///< previous frame time
45 "prev_selected_t", ///< previously selected time
47 "pict_type", ///< the type of picture in the movie
56 "interlace_type", ///< the frame interlace type
61 "n", ///< frame number (starting from zero)
62 "selected_n", ///< selected frame number (starting from zero)
63 "prev_selected_n", ///< number of the last selected frame
65 "key", ///< tell if the frame is a key frame
66 "pos", ///< original position in the file of the frame
79 VAR_PREV_SELECTED_PTS,
116 double var_values[VAR_VARS_NB];
117 int do_scene_detect; ///< 1 if the expression requires scene detection variables, 0 otherwise
118 AVCodecContext *avctx; ///< codec context required for the DSPContext (scene detect only)
119 DSPContext c; ///< context providing optimized SAD methods (scene detect only)
120 double prev_mafd; ///< previous MAFD (scene detect only)
121 AVFilterBufferRef *prev_picref; ///< previous frame (scene detect only)
124 AVFifoBuffer *pending_frames; ///< FIFO buffer of video frames
127 static av_cold int init(AVFilterContext *ctx, const char *args)
129 SelectContext *select = ctx->priv;
132 if ((ret = av_expr_parse(&select->expr, args ? args : "1",
133 var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
134 av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
138 select->pending_frames = av_fifo_alloc(FIFO_SIZE*sizeof(AVFilterBufferRef*));
139 if (!select->pending_frames) {
140 av_log(ctx, AV_LOG_ERROR, "Failed to allocate pending frames buffer.\n");
141 return AVERROR(ENOMEM);
144 select->do_scene_detect = args && strstr(args, "scene");
148 #define INTERLACE_TYPE_P 0
149 #define INTERLACE_TYPE_T 1
150 #define INTERLACE_TYPE_B 2
152 static int config_input(AVFilterLink *inlink)
154 SelectContext *select = inlink->dst->priv;
156 select->var_values[VAR_N] = 0.0;
157 select->var_values[VAR_SELECTED_N] = 0.0;
159 select->var_values[VAR_TB] = av_q2d(inlink->time_base);
161 select->var_values[VAR_PREV_PTS] = NAN;
162 select->var_values[VAR_PREV_SELECTED_PTS] = NAN;
163 select->var_values[VAR_PREV_SELECTED_T] = NAN;
164 select->var_values[VAR_START_PTS] = NAN;
165 select->var_values[VAR_START_T] = NAN;
167 select->var_values[VAR_PICT_TYPE_I] = AV_PICTURE_TYPE_I;
168 select->var_values[VAR_PICT_TYPE_P] = AV_PICTURE_TYPE_P;
169 select->var_values[VAR_PICT_TYPE_B] = AV_PICTURE_TYPE_B;
170 select->var_values[VAR_PICT_TYPE_SI] = AV_PICTURE_TYPE_SI;
171 select->var_values[VAR_PICT_TYPE_SP] = AV_PICTURE_TYPE_SP;
173 select->var_values[VAR_INTERLACE_TYPE_P] = INTERLACE_TYPE_P;
174 select->var_values[VAR_INTERLACE_TYPE_T] = INTERLACE_TYPE_T;
175 select->var_values[VAR_INTERLACE_TYPE_B] = INTERLACE_TYPE_B;
177 if (select->do_scene_detect) {
178 select->avctx = avcodec_alloc_context3(NULL);
180 return AVERROR(ENOMEM);
181 dsputil_init(&select->c, select->avctx);
186 static double get_scene_score(AVFilterContext *ctx, AVFilterBufferRef *picref)
189 SelectContext *select = ctx->priv;
190 AVFilterBufferRef *prev_picref = select->prev_picref;
193 picref->video->h == prev_picref->video->h &&
194 picref->video->w == prev_picref->video->w &&
195 picref->linesize[0] == prev_picref->linesize[0]) {
199 uint8_t *p1 = picref->data[0];
200 uint8_t *p2 = prev_picref->data[0];
201 const int linesize = picref->linesize[0];
203 for (sad = y = 0; y < picref->video->h; y += 8)
204 for (x = 0; x < linesize; x += 8)
205 sad += select->c.sad[1](select,
206 p1 + y * linesize + x,
207 p2 + y * linesize + x,
210 mafd = sad / (picref->video->h * picref->video->w * 3);
211 diff = fabs(mafd - select->prev_mafd);
212 ret = av_clipf(FFMIN(mafd, diff) / 100., 0, 1);
213 select->prev_mafd = mafd;
214 avfilter_unref_buffer(prev_picref);
216 select->prev_picref = avfilter_ref_buffer(picref, ~0);
220 #define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
221 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
223 static int select_frame(AVFilterContext *ctx, AVFilterBufferRef *picref)
225 SelectContext *select = ctx->priv;
226 AVFilterLink *inlink = ctx->inputs[0];
229 if (select->do_scene_detect)
230 select->var_values[VAR_SCENE] = get_scene_score(ctx, picref);
231 if (isnan(select->var_values[VAR_START_PTS]))
232 select->var_values[VAR_START_PTS] = TS2D(picref->pts);
233 if (isnan(select->var_values[VAR_START_T]))
234 select->var_values[VAR_START_T] = TS2D(picref->pts) * av_q2d(inlink->time_base);
236 select->var_values[VAR_PTS] = TS2D(picref->pts);
237 select->var_values[VAR_T ] = TS2D(picref->pts) * av_q2d(inlink->time_base);
238 select->var_values[VAR_POS] = picref->pos == -1 ? NAN : picref->pos;
239 select->var_values[VAR_PREV_PTS] = TS2D(picref ->pts);
241 select->var_values[VAR_INTERLACE_TYPE] =
242 !picref->video->interlaced ? INTERLACE_TYPE_P :
243 picref->video->top_field_first ? INTERLACE_TYPE_T : INTERLACE_TYPE_B;
244 select->var_values[VAR_PICT_TYPE] = picref->video->pict_type;
246 res = av_expr_eval(select->expr, select->var_values, NULL);
247 av_log(inlink->dst, AV_LOG_DEBUG,
248 "n:%d pts:%d t:%f pos:%d interlace_type:%c key:%d pict_type:%c "
250 (int)select->var_values[VAR_N],
251 (int)select->var_values[VAR_PTS],
252 select->var_values[VAR_T],
253 (int)select->var_values[VAR_POS],
254 select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_P ? 'P' :
255 select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_T ? 'T' :
256 select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_B ? 'B' : '?',
257 (int)select->var_values[VAR_KEY],
258 av_get_picture_type_char(select->var_values[VAR_PICT_TYPE]),
261 select->var_values[VAR_N] += 1.0;
264 select->var_values[VAR_PREV_SELECTED_N] = select->var_values[VAR_N];
265 select->var_values[VAR_PREV_SELECTED_PTS] = select->var_values[VAR_PTS];
266 select->var_values[VAR_PREV_SELECTED_T] = select->var_values[VAR_T];
267 select->var_values[VAR_SELECTED_N] += 1.0;
272 static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
274 SelectContext *select = inlink->dst->priv;
276 select->select = select_frame(inlink->dst, picref);
277 if (select->select) {
278 AVFilterBufferRef *buf_out;
279 /* frame was requested through poll_frame */
280 if (select->cache_frames) {
281 if (!av_fifo_space(select->pending_frames))
282 av_log(inlink->dst, AV_LOG_ERROR,
283 "Buffering limit reached, cannot cache more frames\n");
285 av_fifo_generic_write(select->pending_frames, &picref,
286 sizeof(picref), NULL);
289 buf_out = avfilter_ref_buffer(picref, ~0);
291 return AVERROR(ENOMEM);
292 return ff_start_frame(inlink->dst->outputs[0], buf_out);
298 static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
300 SelectContext *select = inlink->dst->priv;
302 if (select->select && !select->cache_frames)
303 return ff_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
307 static int end_frame(AVFilterLink *inlink)
309 SelectContext *select = inlink->dst->priv;
311 if (select->select) {
312 if (select->cache_frames)
314 return ff_end_frame(inlink->dst->outputs[0]);
319 static int request_frame(AVFilterLink *outlink)
321 AVFilterContext *ctx = outlink->src;
322 SelectContext *select = ctx->priv;
323 AVFilterLink *inlink = outlink->src->inputs[0];
326 if (av_fifo_size(select->pending_frames)) {
327 AVFilterBufferRef *picref;
330 av_fifo_generic_read(select->pending_frames, &picref, sizeof(picref), NULL);
331 if ((ret = ff_start_frame(outlink, picref)) < 0 ||
332 (ret = ff_draw_slice(outlink, 0, outlink->h, 1)) < 0 ||
333 (ret = ff_end_frame(outlink)) < 0);
338 while (!select->select) {
339 int ret = ff_request_frame(inlink);
347 static int poll_frame(AVFilterLink *outlink)
349 SelectContext *select = outlink->src->priv;
350 AVFilterLink *inlink = outlink->src->inputs[0];
353 if (!av_fifo_size(select->pending_frames)) {
354 if ((count = ff_poll_frame(inlink)) <= 0)
356 /* request frame from input, and apply select condition to it */
357 select->cache_frames = 1;
358 while (count-- && av_fifo_space(select->pending_frames)) {
359 ret = ff_request_frame(inlink);
363 select->cache_frames = 0;
366 return av_fifo_size(select->pending_frames)/sizeof(AVFilterBufferRef *);
369 static av_cold void uninit(AVFilterContext *ctx)
371 SelectContext *select = ctx->priv;
372 AVFilterBufferRef *picref;
374 av_expr_free(select->expr);
377 while (select->pending_frames &&
378 av_fifo_generic_read(select->pending_frames, &picref, sizeof(picref), NULL) == sizeof(picref))
379 avfilter_unref_buffer(picref);
380 av_fifo_free(select->pending_frames);
381 select->pending_frames = NULL;
383 if (select->do_scene_detect) {
384 avfilter_unref_bufferp(&select->prev_picref);
385 avcodec_close(select->avctx);
386 av_freep(&select->avctx);
390 static int query_formats(AVFilterContext *ctx)
392 SelectContext *select = ctx->priv;
394 if (!select->do_scene_detect) {
395 return ff_default_query_formats(ctx);
397 static const enum PixelFormat pix_fmts[] = {
398 PIX_FMT_RGB24, PIX_FMT_BGR24,
401 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
406 AVFilter avfilter_vf_select = {
408 .description = NULL_IF_CONFIG_SMALL("Select frames to pass in output."),
411 .query_formats = query_formats,
413 .priv_size = sizeof(SelectContext),
415 .inputs = (const AVFilterPad[]) {{ .name = "default",
416 .type = AVMEDIA_TYPE_VIDEO,
417 .get_video_buffer = ff_null_get_video_buffer,
418 .config_props = config_input,
419 .start_frame = start_frame,
420 .draw_slice = draw_slice,
421 .end_frame = end_frame },
423 .outputs = (const AVFilterPad[]) {{ .name = "default",
424 .type = AVMEDIA_TYPE_VIDEO,
425 .poll_frame = poll_frame,
426 .request_frame = request_frame, },