History

lavfi: add select filter

Stefano Sabatini committed 15 years ago

Commit d763fb71 parent 0e7efb96 files · +473 −1Browse files

Unified · Split

6 files
  1. Changelog +1 −0
  2. doc/filters.texi +116 −0
  3. libavfilter/Makefile +1 −0
  4. libavfilter/allfilters.c +1 −0
  5. libavfilter/avfilter.h +1 −1
  6. libavfilter/vf_select.c +353 −0
Changelog+1−0
@@ -46,6 +46,7 @@ easier to use. The changes are: · 45 unmodified lines
46- showinfo filter46- showinfo filter
47- split filter47- split filter
48- libcdio-paranoia input device for audio CD grabbing48- libcdio-paranoia input device for audio CD grabbing
49- select filter
49 50
50 51
51version 0.7:52version 0.7:
doc/filters.texi+116−0
@@ -1064,6 +1064,122 @@ scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub" · 1063 unmodified lines
1064scale='min(500\, iw*3/2):-1'1064scale='min(500\, iw*3/2):-1'
1065@end example1065@end example
1066 1066
1067@section select
1068Select frames to pass in output.
1069
1070It accepts in input an expression, which is evaluated for each input
1071frame. If the expression is evaluated to a non-zero value, the frame
1072is selected and passed to the output, otherwise it is discarded.
1073
1074The expression can contain the following constants:
1075
1076@table @option
1077@item PI
1078Greek PI
1079
1080@item PHI
1081golden ratio
1082
1083@item E
1084Euler number
1085
1086@item n
1087the sequential number of the filtered frame, starting from 0
1088
1089@item selected_n
1090the sequential number of the selected frame, starting from 0
1091
1092@item prev_selected_n
1093the sequential number of the last selected frame, NAN if undefined
1094
1095@item TB
1096timebase of the input timestamps
1097
1098@item pts
1099the PTS (Presentation TimeStamp) of the filtered video frame,
1100expressed in @var{TB} units, NAN if undefined
1101
1102@item t
1103the PTS (Presentation TimeStamp) of the filtered video frame,
1104expressed in seconds, NAN if undefined
1105
1106@item prev_pts
1107the PTS of the previously filtered video frame, NAN if undefined
1108
1109@item prev_selected_pts
1110the PTS of the last previously filtered video frame, NAN if undefined
1111
1112@item prev_selected_t
1113the PTS of the last previously selected video frame, NAN if undefined
1114
1115@item start_pts
1116the PTS of the first video frame in the video, NAN if undefined
1117
1118@item start_t
1119the time of the first video frame in the video, NAN if undefined
1120
1121@item pict_type
1122the type of the filtered frame, can assume one of the following
1123values:
1124@table @option
1125@item I
1126@item P
1127@item B
1128@item S
1129@item SI
1130@item SP
1131@item BI
1132@end table
1133
1134@item interlace_type
1135the frame interlace type, can assume one of the following values:
1136@table @option
1137@item PROGRESSIVE
1138the frame is progressive (not interlaced)
1139@item TOPFIRST
1140the frame is top-field-first
1141@item BOTTOMFIRST
1142the frame is bottom-field-first
1143@end table
1144
1145@item key
11461 if the filtered frame is a key-frame, 0 otherwise
1147
1148@item pos
1149the position in the file of the filtered frame, -1 if the information
1150is not available (e.g. for synthetic video)
1151@end table
1152
1153The default value of the select expression is "1".
1154
1155Some examples follow:
1156
1157@example
1158# select all frames in input
1159select
1160
1161# the above is the same as:
1162select=1
1163
1164# skip all frames:
1165select=0
1166
1167# select only I-frames
1168select='eq(pict_type\,I)'
1169
1170# select one frame every 100
1171select='not(mod(n\,100))'
1172
1173# select only frames contained in the 10-20 time interval
1174select='gte(t\,10)*lte(t\,20)'
1175
1176# select only I frames contained in the 10-20 time interval
1177select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
1178
1179# select frames with a minimum distance of 10 seconds
1180select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
1181@end example
1182
1067@anchor{setdar}1183@anchor{setdar}
1068@section setdar1184@section setdar
1069 1185
libavfilter/Makefile+1−0
@@ -40,6 +40,7 @@ OBJS-$(CONFIG_OVERLAY_FILTER) += vf_overlay.o · 39 unmodified lines
40OBJS-$(CONFIG_PAD_FILTER) += vf_pad.o40OBJS-$(CONFIG_PAD_FILTER) += vf_pad.o
41OBJS-$(CONFIG_PIXDESCTEST_FILTER) += vf_pixdesctest.o41OBJS-$(CONFIG_PIXDESCTEST_FILTER) += vf_pixdesctest.o
42OBJS-$(CONFIG_SCALE_FILTER) += vf_scale.o42OBJS-$(CONFIG_SCALE_FILTER) += vf_scale.o
43OBJS-$(CONFIG_SELECT_FILTER) += vf_select.o
43OBJS-$(CONFIG_SETDAR_FILTER) += vf_aspect.o44OBJS-$(CONFIG_SETDAR_FILTER) += vf_aspect.o
44OBJS-$(CONFIG_SETPTS_FILTER) += vf_setpts.o45OBJS-$(CONFIG_SETPTS_FILTER) += vf_setpts.o
45OBJS-$(CONFIG_SETSAR_FILTER) += vf_aspect.o46OBJS-$(CONFIG_SETSAR_FILTER) += vf_aspect.o
libavfilter/allfilters.c+1−0
@@ -61,6 +61,7 @@ void avfilter_register_all(void) · 60 unmodified lines
61 REGISTER_FILTER (PAD, pad, vf);61 REGISTER_FILTER (PAD, pad, vf);
62 REGISTER_FILTER (PIXDESCTEST, pixdesctest, vf);62 REGISTER_FILTER (PIXDESCTEST, pixdesctest, vf);
63 REGISTER_FILTER (SCALE, scale, vf);63 REGISTER_FILTER (SCALE, scale, vf);
64 REGISTER_FILTER (SELECT, select, vf);
64 REGISTER_FILTER (SETDAR, setdar, vf);65 REGISTER_FILTER (SETDAR, setdar, vf);
65 REGISTER_FILTER (SETPTS, setpts, vf);66 REGISTER_FILTER (SETPTS, setpts, vf);
66 REGISTER_FILTER (SETSAR, setsar, vf);67 REGISTER_FILTER (SETSAR, setsar, vf);
libavfilter/avfilter.h+1−1
@@ -29,7 +29,7 @@ · 28 unmodified lines
29#include "libavutil/rational.h"29#include "libavutil/rational.h"
30 30
31#define LIBAVFILTER_VERSION_MAJOR 231#define LIBAVFILTER_VERSION_MAJOR 2
32#define LIBAVFILTER_VERSION_MINOR 632#define LIBAVFILTER_VERSION_MINOR 7
33#define LIBAVFILTER_VERSION_MICRO 033#define LIBAVFILTER_VERSION_MICRO 0
34 34
35#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \35#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
libavfilter/vf_select.c+353−0
@@ -0,0 +1,353 @@
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
31static const char *var_names[] = {
32 "E", ///< Euler number
33 "PHI", ///< golden ratio
34 "PI", ///< greek pi
35
36 "TB", ///< timebase
37
38 "pts", ///< original pts in the file of the frame
39 "start_pts", ///< first PTS in the stream, expressed in TB units
40 "prev_pts", ///< previous frame PTS
41 "prev_selected_pts", ///< previous selected frame PTS
42
43 "t", ///< first PTS in seconds
44 "start_t", ///< first PTS in the stream, expressed in seconds
45 "prev_t", ///< previous frame time
46 "prev_selected_t", ///< previously selected time
47
48 "pict_type", ///< the type of picture in the movie
49 "I",
50 "P",
51 "B",
52 "S",
53 "SI",
54 "SP",
55 "BI",
56
57 "interlace_type", ///< the frame interlace type
58 "PROGRESSIVE",
59 "TOPFIRST",
60 "BOTTOMFIRST",
61
62 "n", ///< frame number (starting from zero)
63 "selected_n", ///< selected frame number (starting from zero)
64 "prev_selected_n", ///< number of the last selected frame
65
66 "key", ///< tell if the frame is a key frame
67 "pos", ///< original position in the file of the frame
68
69 NULL
70};
71
72enum var_name {
73 VAR_E,
74 VAR_PHI,
75 VAR_PI,
76
77 VAR_TB,
78
79 VAR_PTS,
80 VAR_START_PTS,
81 VAR_PREV_PTS,
82 VAR_PREV_SELECTED_PTS,
83
84 VAR_T,
85 VAR_START_T,
86 VAR_PREV_T,
87 VAR_PREV_SELECTED_T,
88
89 VAR_PICT_TYPE,
90 VAR_PICT_TYPE_I,
91 VAR_PICT_TYPE_P,
92 VAR_PICT_TYPE_B,
93 VAR_PICT_TYPE_S,
94 VAR_PICT_TYPE_SI,
95 VAR_PICT_TYPE_SP,
96 VAR_PICT_TYPE_BI,
97
98 VAR_INTERLACE_TYPE,
99 VAR_INTERLACE_TYPE_P,
100 VAR_INTERLACE_TYPE_T,
101 VAR_INTERLACE_TYPE_B,
102
103 VAR_N,
104 VAR_SELECTED_N,
105 VAR_PREV_SELECTED_N,
106
107 VAR_KEY,
108 VAR_POS,
109
110 VAR_VARS_NB
111};
112
113#define FIFO_SIZE 8
114
115typedef struct {
116 AVExpr *expr;
117 double var_values[VAR_VARS_NB];
118 double select;
119 int cache_frames;
120 AVFifoBuffer *pending_frames; ///< FIFO buffer of video frames
121} SelectContext;
122
123static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
124{
125 SelectContext *select = ctx->priv;
126 int ret;
127
128 if ((ret = av_expr_parse(&select->expr, args ? args : "1",
129 var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
130 av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
131 return ret;
132 }
133
134 select->pending_frames = av_fifo_alloc(FIFO_SIZE*sizeof(AVFilterBufferRef*));
135 if (!select->pending_frames) {
136 av_log(ctx, AV_LOG_ERROR, "Failed to allocate pending frames buffer.\n");
137 return AVERROR(ENOMEM);
138 }
139 return 0;
140}
141
142#define INTERLACE_TYPE_P 0
143#define INTERLACE_TYPE_T 1
144#define INTERLACE_TYPE_B 2
145
146static int config_input(AVFilterLink *inlink)
147{
148 SelectContext *select = inlink->dst->priv;
149
150 select->var_values[VAR_E] = M_E;
151 select->var_values[VAR_PHI] = M_PHI;
152 select->var_values[VAR_PI] = M_PI;
153
154 select->var_values[VAR_N] = 0.0;
155 select->var_values[VAR_SELECTED_N] = 0.0;
156
157 select->var_values[VAR_TB] = av_q2d(inlink->time_base);
158
159 select->var_values[VAR_PREV_PTS] = NAN;
160 select->var_values[VAR_PREV_SELECTED_PTS] = NAN;
161 select->var_values[VAR_PREV_SELECTED_T] = NAN;
162 select->var_values[VAR_START_PTS] = NAN;
163 select->var_values[VAR_START_T] = NAN;
164
165 select->var_values[VAR_PICT_TYPE_I] = AV_PICTURE_TYPE_I;
166 select->var_values[VAR_PICT_TYPE_P] = AV_PICTURE_TYPE_P;
167 select->var_values[VAR_PICT_TYPE_B] = AV_PICTURE_TYPE_B;
168 select->var_values[VAR_PICT_TYPE_SI] = AV_PICTURE_TYPE_SI;
169 select->var_values[VAR_PICT_TYPE_SP] = AV_PICTURE_TYPE_SP;
170
171 select->var_values[VAR_INTERLACE_TYPE_P] = INTERLACE_TYPE_P;
172 select->var_values[VAR_INTERLACE_TYPE_T] = INTERLACE_TYPE_T;
173 select->var_values[VAR_INTERLACE_TYPE_B] = INTERLACE_TYPE_B;;
174
175 return 0;
176}
177
178#define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
179#define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
180
181static int select_frame(AVFilterContext *ctx, AVFilterBufferRef *picref)
182{
183 SelectContext *select = ctx->priv;
184 AVFilterLink *inlink = ctx->inputs[0];
185 double res;
186
187 if (isnan(select->var_values[VAR_START_PTS]))
188 select->var_values[VAR_START_PTS] = TS2D(picref->pts);
189 if (isnan(select->var_values[VAR_START_T]))
190 select->var_values[VAR_START_T] = TS2D(picref->pts) * av_q2d(inlink->time_base);
191
192 select->var_values[VAR_PTS] = TS2D(picref->pts);
193 select->var_values[VAR_T ] = TS2D(picref->pts) * av_q2d(inlink->time_base);
194 select->var_values[VAR_POS] = picref->pos == -1 ? NAN : picref->pos;
195 select->var_values[VAR_PREV_PTS] = TS2D(picref ->pts);
196
197 select->var_values[VAR_INTERLACE_TYPE] =
198 !picref->video->interlaced ? INTERLACE_TYPE_P :
199 picref->video->top_field_first ? INTERLACE_TYPE_T : INTERLACE_TYPE_B;
200 select->var_values[VAR_PICT_TYPE] = picref->video->pict_type;
201
202 res = av_expr_eval(select->expr, select->var_values, NULL);
203 av_log(inlink->dst, AV_LOG_DEBUG,
204 "n:%d pts:%d t:%f pos:%d interlace_type:%c key:%d pict_type:%c "
205 "-> select:%f\n",
206 (int)select->var_values[VAR_N],
207 (int)select->var_values[VAR_PTS],
208 select->var_values[VAR_T],
209 (int)select->var_values[VAR_POS],
210 select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_P ? 'P' :
211 select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_T ? 'T' :
212 select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_B ? 'B' : '?',
213 (int)select->var_values[VAR_KEY],
214 av_get_picture_type_char(select->var_values[VAR_PICT_TYPE]),
215 res);
216
217 select->var_values[VAR_N] += 1.0;
218
219 if (res) {
220 select->var_values[VAR_PREV_SELECTED_N] = select->var_values[VAR_N];
221 select->var_values[VAR_PREV_SELECTED_PTS] = select->var_values[VAR_PTS];
222 select->var_values[VAR_PREV_SELECTED_T] = select->var_values[VAR_T];
223 select->var_values[VAR_SELECTED_N] += 1.0;
224 }
225 return res;
226}
227
228static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
229{
230 SelectContext *select = inlink->dst->priv;
231
232 select->select = select_frame(inlink->dst, picref);
233 if (select->select) {
234 /* frame was requested through poll_frame */
235 if (select->cache_frames) {
236 if (!av_fifo_space(select->pending_frames))
237 av_log(inlink->dst, AV_LOG_ERROR,
238 "Buffering limit reached, cannot cache more frames\n");
239 else
240 av_fifo_generic_write(select->pending_frames, &picref,
241 sizeof(picref), NULL);
242 return;
243 }
244 avfilter_start_frame(inlink->dst->outputs[0], avfilter_ref_buffer(picref, ~0));
245 }
246}
247
248static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
249{
250 SelectContext *select = inlink->dst->priv;
251
252 if (select->select && !select->cache_frames)
253 avfilter_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
254}
255
256static void end_frame(AVFilterLink *inlink)
257{
258 SelectContext *select = inlink->dst->priv;
259 AVFilterBufferRef *picref = inlink->cur_buf;
260
261 if (select->select) {
262 if (select->cache_frames)
263 return;
264 avfilter_end_frame(inlink->dst->outputs[0]);
265 }
266 avfilter_unref_buffer(picref);
267}
268
269static int request_frame(AVFilterLink *outlink)
270{
271 AVFilterContext *ctx = outlink->src;
272 SelectContext *select = ctx->priv;
273 AVFilterLink *inlink = outlink->src->inputs[0];
274 select->select = 0;
275
276 if (av_fifo_size(select->pending_frames)) {
277 AVFilterBufferRef *picref;
278 av_fifo_generic_read(select->pending_frames, &picref, sizeof(picref), NULL);
279 avfilter_start_frame(outlink, avfilter_ref_buffer(picref, ~0));
280 avfilter_draw_slice(outlink, 0, outlink->h, 1);
281 avfilter_end_frame(outlink);
282 avfilter_unref_buffer(picref);
283 return 0;
284 }
285
286 while (!select->select) {
287 int ret = avfilter_request_frame(inlink);
288 if (ret < 0)
289 return ret;
290 }
291
292 return 0;
293}
294
295static int poll_frame(AVFilterLink *outlink)
296{
297 SelectContext *select = outlink->src->priv;
298 AVFilterLink *inlink = outlink->src->inputs[0];
299 int count, ret;
300
301 if (!av_fifo_size(select->pending_frames)) {
302 if ((count = avfilter_poll_frame(inlink)) <= 0)
303 return count;
304 /* request frame from input, and apply select condition to it */
305 select->cache_frames = 1;
306 while (count-- && av_fifo_space(select->pending_frames)) {
307 ret = avfilter_request_frame(inlink);
308 if (ret < 0)
309 break;
310 }
311 select->cache_frames = 0;
312 }
313
314 return av_fifo_size(select->pending_frames)/sizeof(AVFilterBufferRef *);
315}
316
317static av_cold void uninit(AVFilterContext *ctx)
318{
319 SelectContext *select = ctx->priv;
320 AVFilterBufferRef *picref;
321
322 av_expr_free(select->expr);
323 select->expr = NULL;
324
325 while (select->pending_frames &&
326 av_fifo_generic_read(select->pending_frames, &picref, sizeof(picref), NULL) == sizeof(picref))
327 avfilter_unref_buffer(picref);
328 av_fifo_free(select->pending_frames);
329 select->pending_frames = NULL;
330}
331
332AVFilter avfilter_vf_select = {
333 .name = "select",
334 .description = NULL_IF_CONFIG_SMALL("Select frames to pass in output."),
335 .init = init,
336 .uninit = uninit,
337
338 .priv_size = sizeof(SelectContext),
339
340 .inputs = (AVFilterPad[]) {{ .name = "default",
341 .type = AVMEDIA_TYPE_VIDEO,
342 .get_video_buffer = avfilter_null_get_video_buffer,
343 .config_props = config_input,
344 .start_frame = start_frame,
345 .draw_slice = draw_slice,
346 .end_frame = end_frame },
347 { .name = NULL }},
348 .outputs = (AVFilterPad[]) {{ .name = "default",
349 .type = AVMEDIA_TYPE_VIDEO,
350 .poll_frame = poll_frame,
351 .request_frame = request_frame, },
352 { .name = NULL}},
353};

Keyboard shortcuts

General

Show keyboard shortcuts
?
Focus the current search
/

Issues and pull requests

Open filters
f

Issues, pull requests and Inbox

Select next item
j↓
Select previous item
k↑
Open selected item
Enter
Dismiss filters or clear selection
Esc

Repository code

Go to file
t