lavfi: add error handling to start_frame().
[libav.git] / libavfilter / vf_select.c
1 /*
2 * Copyright (c) 2011 Stefano Sabatini
3 *
4 * This file is part of Libav.
5 *
6 * Libav 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 * Libav 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 Libav; 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/eval.h"
27 #include "libavutil/fifo.h"
28 #include "libavutil/mathematics.h"
29 #include "avfilter.h"
30 #include "internal.h"
31 #include "video.h"
32
33 static const char *const var_names[] = {
34 "E", ///< Euler number
35 "PHI", ///< golden ratio
36 "PI", ///< greek pi
37
38 "TB", ///< timebase
39
40 "pts", ///< original pts in the file of the frame
41 "start_pts", ///< first PTS in the stream, expressed in TB units
42 "prev_pts", ///< previous frame PTS
43 "prev_selected_pts", ///< previous selected frame PTS
44
45 "t", ///< first PTS in seconds
46 "start_t", ///< first PTS in the stream, expressed in seconds
47 "prev_t", ///< previous frame time
48 "prev_selected_t", ///< previously selected time
49
50 "pict_type", ///< the type of picture in the movie
51 "I",
52 "P",
53 "B",
54 "S",
55 "SI",
56 "SP",
57 "BI",
58
59 "interlace_type", ///< the frame interlace type
60 "PROGRESSIVE",
61 "TOPFIRST",
62 "BOTTOMFIRST",
63
64 "n", ///< frame number (starting from zero)
65 "selected_n", ///< selected frame number (starting from zero)
66 "prev_selected_n", ///< number of the last selected frame
67
68 "key", ///< tell if the frame is a key frame
69 "pos", ///< original position in the file of the frame
70
71 NULL
72 };
73
74 enum var_name {
75 VAR_E,
76 VAR_PHI,
77 VAR_PI,
78
79 VAR_TB,
80
81 VAR_PTS,
82 VAR_START_PTS,
83 VAR_PREV_PTS,
84 VAR_PREV_SELECTED_PTS,
85
86 VAR_T,
87 VAR_START_T,
88 VAR_PREV_T,
89 VAR_PREV_SELECTED_T,
90
91 VAR_PICT_TYPE,
92 VAR_PICT_TYPE_I,
93 VAR_PICT_TYPE_P,
94 VAR_PICT_TYPE_B,
95 VAR_PICT_TYPE_S,
96 VAR_PICT_TYPE_SI,
97 VAR_PICT_TYPE_SP,
98 VAR_PICT_TYPE_BI,
99
100 VAR_INTERLACE_TYPE,
101 VAR_INTERLACE_TYPE_P,
102 VAR_INTERLACE_TYPE_T,
103 VAR_INTERLACE_TYPE_B,
104
105 VAR_N,
106 VAR_SELECTED_N,
107 VAR_PREV_SELECTED_N,
108
109 VAR_KEY,
110 VAR_POS,
111
112 VAR_VARS_NB
113 };
114
115 #define FIFO_SIZE 8
116
117 typedef struct {
118 AVExpr *expr;
119 double var_values[VAR_VARS_NB];
120 double select;
121 int cache_frames;
122 AVFifoBuffer *pending_frames; ///< FIFO buffer of video frames
123 } SelectContext;
124
125 static av_cold int init(AVFilterContext *ctx, const char *args)
126 {
127 SelectContext *select = ctx->priv;
128 int ret;
129
130 if ((ret = av_expr_parse(&select->expr, args ? args : "1",
131 var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
132 av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
133 return ret;
134 }
135
136 select->pending_frames = av_fifo_alloc(FIFO_SIZE*sizeof(AVFilterBufferRef*));
137 if (!select->pending_frames) {
138 av_log(ctx, AV_LOG_ERROR, "Failed to allocate pending frames buffer.\n");
139 return AVERROR(ENOMEM);
140 }
141 return 0;
142 }
143
144 #define INTERLACE_TYPE_P 0
145 #define INTERLACE_TYPE_T 1
146 #define INTERLACE_TYPE_B 2
147
148 static int config_input(AVFilterLink *inlink)
149 {
150 SelectContext *select = inlink->dst->priv;
151
152 select->var_values[VAR_E] = M_E;
153 select->var_values[VAR_PHI] = M_PHI;
154 select->var_values[VAR_PI] = M_PI;
155
156 select->var_values[VAR_N] = 0.0;
157 select->var_values[VAR_SELECTED_N] = 0.0;
158
159 select->var_values[VAR_TB] = av_q2d(inlink->time_base);
160
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;
166
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;
172
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;;
176
177 return 0;
178 }
179
180 #define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
181 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
182
183 static int select_frame(AVFilterContext *ctx, AVFilterBufferRef *picref)
184 {
185 SelectContext *select = ctx->priv;
186 AVFilterLink *inlink = ctx->inputs[0];
187 double res;
188
189 if (isnan(select->var_values[VAR_START_PTS]))
190 select->var_values[VAR_START_PTS] = TS2D(picref->pts);
191 if (isnan(select->var_values[VAR_START_T]))
192 select->var_values[VAR_START_T] = TS2D(picref->pts) * av_q2d(inlink->time_base);
193
194 select->var_values[VAR_PTS] = TS2D(picref->pts);
195 select->var_values[VAR_T ] = TS2D(picref->pts) * av_q2d(inlink->time_base);
196 select->var_values[VAR_POS] = picref->pos == -1 ? NAN : picref->pos;
197 select->var_values[VAR_PREV_PTS] = TS2D(picref ->pts);
198
199 select->var_values[VAR_INTERLACE_TYPE] =
200 !picref->video->interlaced ? INTERLACE_TYPE_P :
201 picref->video->top_field_first ? INTERLACE_TYPE_T : INTERLACE_TYPE_B;
202 select->var_values[VAR_PICT_TYPE] = picref->video->pict_type;
203
204 res = av_expr_eval(select->expr, select->var_values, NULL);
205 av_log(inlink->dst, AV_LOG_DEBUG,
206 "n:%d pts:%d t:%f pos:%d interlace_type:%c key:%d pict_type:%c "
207 "-> select:%f\n",
208 (int)select->var_values[VAR_N],
209 (int)select->var_values[VAR_PTS],
210 select->var_values[VAR_T],
211 (int)select->var_values[VAR_POS],
212 select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_P ? 'P' :
213 select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_T ? 'T' :
214 select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_B ? 'B' : '?',
215 (int)select->var_values[VAR_KEY],
216 av_get_picture_type_char(select->var_values[VAR_PICT_TYPE]),
217 res);
218
219 select->var_values[VAR_N] += 1.0;
220
221 if (res) {
222 select->var_values[VAR_PREV_SELECTED_N] = select->var_values[VAR_N];
223 select->var_values[VAR_PREV_SELECTED_PTS] = select->var_values[VAR_PTS];
224 select->var_values[VAR_PREV_SELECTED_T] = select->var_values[VAR_T];
225 select->var_values[VAR_SELECTED_N] += 1.0;
226 }
227 return res;
228 }
229
230 static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
231 {
232 SelectContext *select = inlink->dst->priv;
233
234 select->select = select_frame(inlink->dst, picref);
235 if (select->select) {
236 /* frame was requested through poll_frame */
237 if (select->cache_frames) {
238 if (!av_fifo_space(select->pending_frames))
239 av_log(inlink->dst, AV_LOG_ERROR,
240 "Buffering limit reached, cannot cache more frames\n");
241 else
242 av_fifo_generic_write(select->pending_frames, &picref,
243 sizeof(picref), NULL);
244 return 0;
245 }
246 return ff_start_frame(inlink->dst->outputs[0], avfilter_ref_buffer(picref, ~0));
247 }
248
249 return 0;
250 }
251
252 static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
253 {
254 SelectContext *select = inlink->dst->priv;
255
256 if (select->select && !select->cache_frames)
257 ff_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
258 }
259
260 static void end_frame(AVFilterLink *inlink)
261 {
262 SelectContext *select = inlink->dst->priv;
263
264 if (select->select) {
265 if (select->cache_frames)
266 return;
267 ff_end_frame(inlink->dst->outputs[0]);
268 }
269 }
270
271 static int request_frame(AVFilterLink *outlink)
272 {
273 AVFilterContext *ctx = outlink->src;
274 SelectContext *select = ctx->priv;
275 AVFilterLink *inlink = outlink->src->inputs[0];
276 select->select = 0;
277
278 if (av_fifo_size(select->pending_frames)) {
279 AVFilterBufferRef *picref;
280 av_fifo_generic_read(select->pending_frames, &picref, sizeof(picref), NULL);
281 ff_start_frame(outlink, avfilter_ref_buffer(picref, ~0));
282 ff_draw_slice(outlink, 0, outlink->h, 1);
283 ff_end_frame(outlink);
284 avfilter_unref_buffer(picref);
285 return 0;
286 }
287
288 while (!select->select) {
289 int ret = ff_request_frame(inlink);
290 if (ret < 0)
291 return ret;
292 }
293
294 return 0;
295 }
296
297 static int poll_frame(AVFilterLink *outlink)
298 {
299 SelectContext *select = outlink->src->priv;
300 AVFilterLink *inlink = outlink->src->inputs[0];
301 int count, ret;
302
303 if (!av_fifo_size(select->pending_frames)) {
304 if ((count = ff_poll_frame(inlink)) <= 0)
305 return count;
306 /* request frame from input, and apply select condition to it */
307 select->cache_frames = 1;
308 while (count-- && av_fifo_space(select->pending_frames)) {
309 ret = ff_request_frame(inlink);
310 if (ret < 0)
311 break;
312 }
313 select->cache_frames = 0;
314 }
315
316 return av_fifo_size(select->pending_frames)/sizeof(AVFilterBufferRef *);
317 }
318
319 static av_cold void uninit(AVFilterContext *ctx)
320 {
321 SelectContext *select = ctx->priv;
322 AVFilterBufferRef *picref;
323
324 av_expr_free(select->expr);
325 select->expr = NULL;
326
327 while (select->pending_frames &&
328 av_fifo_generic_read(select->pending_frames, &picref, sizeof(picref), NULL) == sizeof(picref))
329 avfilter_unref_buffer(picref);
330 av_fifo_free(select->pending_frames);
331 select->pending_frames = NULL;
332 }
333
334 AVFilter avfilter_vf_select = {
335 .name = "select",
336 .description = NULL_IF_CONFIG_SMALL("Select frames to pass in output."),
337 .init = init,
338 .uninit = uninit,
339
340 .priv_size = sizeof(SelectContext),
341
342 .inputs = (const AVFilterPad[]) {{ .name = "default",
343 .type = AVMEDIA_TYPE_VIDEO,
344 .get_video_buffer = ff_null_get_video_buffer,
345 .config_props = config_input,
346 .start_frame = start_frame,
347 .draw_slice = draw_slice,
348 .end_frame = end_frame },
349 { .name = NULL }},
350 .outputs = (const AVFilterPad[]) {{ .name = "default",
351 .type = AVMEDIA_TYPE_VIDEO,
352 .poll_frame = poll_frame,
353 .request_frame = request_frame, },
354 { .name = NULL}},
355 };