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path: root/libavfilter/vf_fps.c (plain)
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1/*
2 * Copyright 2007 Bobby Bingham
3 * Copyright 2012 Robert Nagy <ronag89 gmail com>
4 * Copyright 2012 Anton Khirnov <anton khirnov net>
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23/**
24 * @file
25 * a filter enforcing given constant framerate
26 */
27
28#include <float.h>
29#include <stdint.h>
30
31#include "libavutil/common.h"
32#include "libavutil/fifo.h"
33#include "libavutil/mathematics.h"
34#include "libavutil/opt.h"
35#include "libavutil/parseutils.h"
36
37#include "avfilter.h"
38#include "internal.h"
39#include "video.h"
40
41typedef struct FPSContext {
42 const AVClass *class;
43
44 AVFifoBuffer *fifo; ///< store frames until we get two successive timestamps
45
46 /* timestamps in input timebase */
47 int64_t first_pts; ///< pts of the first frame that arrived on this filter
48
49 double start_time; ///< pts, in seconds, of the expected first frame
50
51 AVRational framerate; ///< target framerate
52 int rounding; ///< AVRounding method for timestamps
53
54 /* statistics */
55 int frames_in; ///< number of frames on input
56 int frames_out; ///< number of frames on output
57 int dup; ///< number of frames duplicated
58 int drop; ///< number of framed dropped
59} FPSContext;
60
61#define OFFSET(x) offsetof(FPSContext, x)
62#define V AV_OPT_FLAG_VIDEO_PARAM
63#define F AV_OPT_FLAG_FILTERING_PARAM
64static const AVOption fps_options[] = {
65 { "fps", "A string describing desired output framerate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, { .str = "25" }, 0, INT_MAX, V|F },
66 { "start_time", "Assume the first PTS should be this value.", OFFSET(start_time), AV_OPT_TYPE_DOUBLE, { .dbl = DBL_MAX}, -DBL_MAX, DBL_MAX, V },
67 { "round", "set rounding method for timestamps", OFFSET(rounding), AV_OPT_TYPE_INT, { .i64 = AV_ROUND_NEAR_INF }, 0, 5, V|F, "round" },
68 { "zero", "round towards 0", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_ZERO }, 0, 5, V|F, "round" },
69 { "inf", "round away from 0", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_INF }, 0, 5, V|F, "round" },
70 { "down", "round towards -infty", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_DOWN }, 0, 5, V|F, "round" },
71 { "up", "round towards +infty", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_UP }, 0, 5, V|F, "round" },
72 { "near", "round to nearest", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_NEAR_INF }, 0, 5, V|F, "round" },
73 { NULL }
74};
75
76AVFILTER_DEFINE_CLASS(fps);
77
78static av_cold int init(AVFilterContext *ctx)
79{
80 FPSContext *s = ctx->priv;
81
82 if (!(s->fifo = av_fifo_alloc_array(2, sizeof(AVFrame*))))
83 return AVERROR(ENOMEM);
84
85 s->first_pts = AV_NOPTS_VALUE;
86
87 av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);
88 return 0;
89}
90
91static void flush_fifo(AVFifoBuffer *fifo)
92{
93 while (av_fifo_size(fifo)) {
94 AVFrame *tmp;
95 av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);
96 av_frame_free(&tmp);
97 }
98}
99
100static av_cold void uninit(AVFilterContext *ctx)
101{
102 FPSContext *s = ctx->priv;
103 if (s->fifo) {
104 s->drop += av_fifo_size(s->fifo) / sizeof(AVFrame*);
105 flush_fifo(s->fifo);
106 av_fifo_freep(&s->fifo);
107 }
108
109 av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
110 "%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);
111}
112
113static int config_props(AVFilterLink* link)
114{
115 FPSContext *s = link->src->priv;
116
117 link->time_base = av_inv_q(s->framerate);
118 link->frame_rate= s->framerate;
119 link->w = link->src->inputs[0]->w;
120 link->h = link->src->inputs[0]->h;
121
122 return 0;
123}
124
125static int request_frame(AVFilterLink *outlink)
126{
127 AVFilterContext *ctx = outlink->src;
128 FPSContext *s = ctx->priv;
129 int ret;
130
131 ret = ff_request_frame(ctx->inputs[0]);
132
133 /* flush the fifo */
134 if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {
135 int i;
136 for (i = 0; av_fifo_size(s->fifo); i++) {
137 AVFrame *buf;
138
139 av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);
140 buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,
141 outlink->time_base) + s->frames_out;
142
143 if ((ret = ff_filter_frame(outlink, buf)) < 0)
144 return ret;
145
146 s->frames_out++;
147 }
148 return 0;
149 }
150
151 return ret;
152}
153
154static int write_to_fifo(AVFifoBuffer *fifo, AVFrame *buf)
155{
156 int ret;
157
158 if (!av_fifo_space(fifo) &&
159 (ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo)))) {
160 av_frame_free(&buf);
161 return ret;
162 }
163
164 av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);
165 return 0;
166}
167
168static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
169{
170 AVFilterContext *ctx = inlink->dst;
171 FPSContext *s = ctx->priv;
172 AVFilterLink *outlink = ctx->outputs[0];
173 int64_t delta;
174 int i, ret;
175
176 s->frames_in++;
177 /* discard frames until we get the first timestamp */
178 if (s->first_pts == AV_NOPTS_VALUE) {
179 if (buf->pts != AV_NOPTS_VALUE) {
180 ret = write_to_fifo(s->fifo, buf);
181 if (ret < 0)
182 return ret;
183
184 if (s->start_time != DBL_MAX && s->start_time != AV_NOPTS_VALUE) {
185 double first_pts = s->start_time * AV_TIME_BASE;
186 first_pts = FFMIN(FFMAX(first_pts, INT64_MIN), INT64_MAX);
187 s->first_pts = av_rescale_q(first_pts, AV_TIME_BASE_Q,
188 inlink->time_base);
189 av_log(ctx, AV_LOG_VERBOSE, "Set first pts to (in:%"PRId64" out:%"PRId64")\n",
190 s->first_pts, av_rescale_q(first_pts, AV_TIME_BASE_Q,
191 outlink->time_base));
192 } else {
193 s->first_pts = buf->pts;
194 }
195 } else {
196 av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "
197 "timestamp.\n");
198 av_frame_free(&buf);
199 s->drop++;
200 }
201 return 0;
202 }
203
204 /* now wait for the next timestamp */
205 if (buf->pts == AV_NOPTS_VALUE || av_fifo_size(s->fifo) <= 0) {
206 return write_to_fifo(s->fifo, buf);
207 }
208
209 /* number of output frames */
210 delta = av_rescale_q_rnd(buf->pts - s->first_pts, inlink->time_base,
211 outlink->time_base, s->rounding) - s->frames_out ;
212
213 if (delta < 1) {
214 /* drop everything buffered except the last */
215 int drop = av_fifo_size(s->fifo)/sizeof(AVFrame*);
216
217 av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);
218 s->drop += drop;
219
220 flush_fifo(s->fifo);
221 ret = write_to_fifo(s->fifo, buf);
222
223 return ret;
224 }
225
226 /* can output >= 1 frames */
227 for (i = 0; i < delta; i++) {
228 AVFrame *buf_out;
229 av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);
230
231 /* duplicate the frame if needed */
232 if (!av_fifo_size(s->fifo) && i < delta - 1) {
233 AVFrame *dup = av_frame_clone(buf_out);
234
235 av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");
236 if (dup)
237 ret = write_to_fifo(s->fifo, dup);
238 else
239 ret = AVERROR(ENOMEM);
240
241 if (ret < 0) {
242 av_frame_free(&buf_out);
243 av_frame_free(&buf);
244 return ret;
245 }
246
247 s->dup++;
248 }
249
250 buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,
251 outlink->time_base) + s->frames_out;
252
253 if ((ret = ff_filter_frame(outlink, buf_out)) < 0) {
254 av_frame_free(&buf);
255 return ret;
256 }
257
258 s->frames_out++;
259 }
260 flush_fifo(s->fifo);
261
262 ret = write_to_fifo(s->fifo, buf);
263
264 return ret;
265}
266
267static const AVFilterPad avfilter_vf_fps_inputs[] = {
268 {
269 .name = "default",
270 .type = AVMEDIA_TYPE_VIDEO,
271 .filter_frame = filter_frame,
272 },
273 { NULL }
274};
275
276static const AVFilterPad avfilter_vf_fps_outputs[] = {
277 {
278 .name = "default",
279 .type = AVMEDIA_TYPE_VIDEO,
280 .request_frame = request_frame,
281 .config_props = config_props
282 },
283 { NULL }
284};
285
286AVFilter ff_vf_fps = {
287 .name = "fps",
288 .description = NULL_IF_CONFIG_SMALL("Force constant framerate."),
289 .init = init,
290 .uninit = uninit,
291 .priv_size = sizeof(FPSContext),
292 .priv_class = &fps_class,
293 .inputs = avfilter_vf_fps_inputs,
294 .outputs = avfilter_vf_fps_outputs,
295};
296
generated by cgit at 2024-05-17 18:39:39 (GMT)