2 * Copyright 2007 Bobby Bingham
3 * Copyright 2012 Robert Nagy <ronag89 gmail com>
4 * Copyright 2012 Anton Khirnov <anton khirnov net>
6 * This file is part of FFmpeg.
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.
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.
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
25 * a filter enforcing given constant framerate
28 #include "libavutil/common.h"
29 #include "libavutil/fifo.h"
30 #include "libavutil/mathematics.h"
31 #include "libavutil/opt.h"
32 #include "libavutil/parseutils.h"
38 typedef struct FPSContext {
41 AVFifoBuffer *fifo; ///< store frames until we get two successive timestamps
43 /* timestamps in input timebase */
44 int64_t first_pts; ///< pts of the first frame that arrived on this filter
45 int64_t pts; ///< pts of the first frame currently in the fifo
47 AVRational framerate; ///< target framerate
48 char *fps; ///< a string describing target framerate
49 int rounding; ///< AVRounding method for timestamps
52 int frames_in; ///< number of frames on input
53 int frames_out; ///< number of frames on output
54 int dup; ///< number of frames duplicated
55 int drop; ///< number of framed dropped
58 #define OFFSET(x) offsetof(FPSContext, x)
59 #define V AV_OPT_FLAG_VIDEO_PARAM
60 #define F AV_OPT_FLAG_FILTERING_PARAM
61 static const AVOption fps_options[] = {
62 { "fps", "A string describing desired output framerate", OFFSET(fps), AV_OPT_TYPE_STRING, { .str = "25" }, .flags = V|F },
63 { "round", "set rounding method for timestamps", OFFSET(rounding), AV_OPT_TYPE_INT, { .i64 = AV_ROUND_NEAR_INF }, 0, 5, V|F, "round" },
64 { "zero", "round towards 0", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_ZERO }, 0, 5, V|F, "round" },
65 { "inf", "round away from 0", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_INF }, 0, 5, V|F, "round" },
66 { "down", "round towards -infty", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_DOWN }, 0, 5, V|F, "round" },
67 { "up", "round towards +infty", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_UP }, 0, 5, V|F, "round" },
68 { "near", "round to nearest", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_NEAR_INF }, 0, 5, V|F, "round" },
72 AVFILTER_DEFINE_CLASS(fps);
74 static av_cold int init(AVFilterContext *ctx, const char *args)
76 FPSContext *s = ctx->priv;
77 const char *shorthand[] = { "fps", "round", NULL };
80 s->class = &fps_class;
81 av_opt_set_defaults(s);
83 if ((ret = av_opt_set_from_string(s, args, shorthand, "=", ":")) < 0)
86 if ((ret = av_parse_video_rate(&s->framerate, s->fps)) < 0) {
87 av_log(ctx, AV_LOG_ERROR, "Error parsing framerate %s.\n", s->fps);
92 if (!(s->fifo = av_fifo_alloc(2*sizeof(AVFilterBufferRef*))))
93 return AVERROR(ENOMEM);
95 av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);
99 static void flush_fifo(AVFifoBuffer *fifo)
101 while (av_fifo_size(fifo)) {
102 AVFilterBufferRef *tmp;
103 av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);
104 avfilter_unref_buffer(tmp);
108 static av_cold void uninit(AVFilterContext *ctx)
110 FPSContext *s = ctx->priv;
113 av_fifo_free(s->fifo);
116 av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
117 "%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);
120 static int config_props(AVFilterLink* link)
122 FPSContext *s = link->src->priv;
124 link->time_base = av_inv_q(s->framerate);
125 link->frame_rate= s->framerate;
126 link->w = link->src->inputs[0]->w;
127 link->h = link->src->inputs[0]->h;
128 s->pts = AV_NOPTS_VALUE;
133 static int request_frame(AVFilterLink *outlink)
135 AVFilterContext *ctx = outlink->src;
136 FPSContext *s = ctx->priv;
137 int frames_out = s->frames_out;
140 while (ret >= 0 && s->frames_out == frames_out)
141 ret = ff_request_frame(ctx->inputs[0]);
144 if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {
146 for (i = 0; av_fifo_size(s->fifo); i++) {
147 AVFilterBufferRef *buf;
149 av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);
150 buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,
151 outlink->time_base) + s->frames_out;
153 if ((ret = ff_filter_frame(outlink, buf)) < 0)
164 static int write_to_fifo(AVFifoBuffer *fifo, AVFilterBufferRef *buf)
168 if (!av_fifo_space(fifo) &&
169 (ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo)))) {
170 avfilter_unref_bufferp(&buf);
174 av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);
178 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *buf)
180 AVFilterContext *ctx = inlink->dst;
181 FPSContext *s = ctx->priv;
182 AVFilterLink *outlink = ctx->outputs[0];
187 /* discard frames until we get the first timestamp */
188 if (s->pts == AV_NOPTS_VALUE) {
189 if (buf->pts != AV_NOPTS_VALUE) {
190 ret = write_to_fifo(s->fifo, buf);
194 s->first_pts = s->pts = buf->pts;
196 av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "
198 avfilter_unref_buffer(buf);
204 /* now wait for the next timestamp */
205 if (buf->pts == AV_NOPTS_VALUE) {
206 return write_to_fifo(s->fifo, buf);
209 /* number of output frames */
210 delta = av_rescale_q_rnd(buf->pts - s->pts, inlink->time_base,
211 outlink->time_base, s->rounding);
214 /* drop the frame and everything buffered except the first */
215 AVFilterBufferRef *tmp;
216 int drop = av_fifo_size(s->fifo)/sizeof(AVFilterBufferRef*);
218 av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);
221 av_fifo_generic_read(s->fifo, &tmp, sizeof(tmp), NULL);
223 ret = write_to_fifo(s->fifo, tmp);
225 avfilter_unref_buffer(buf);
229 /* can output >= 1 frames */
230 for (i = 0; i < delta; i++) {
231 AVFilterBufferRef *buf_out;
232 av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);
234 /* duplicate the frame if needed */
235 if (!av_fifo_size(s->fifo) && i < delta - 1) {
236 AVFilterBufferRef *dup = avfilter_ref_buffer(buf_out, ~0);
238 av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");
240 ret = write_to_fifo(s->fifo, dup);
242 ret = AVERROR(ENOMEM);
245 avfilter_unref_bufferp(&buf_out);
246 avfilter_unref_bufferp(&buf);
253 buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,
254 outlink->time_base) + s->frames_out;
256 if ((ret = ff_filter_frame(outlink, buf_out)) < 0) {
257 avfilter_unref_bufferp(&buf);
265 ret = write_to_fifo(s->fifo, buf);
266 s->pts = s->first_pts + av_rescale_q(s->frames_out, outlink->time_base, inlink->time_base);
271 static const AVFilterPad avfilter_vf_fps_inputs[] = {
274 .type = AVMEDIA_TYPE_VIDEO,
275 .min_perms = AV_PERM_READ | AV_PERM_PRESERVE,
276 .filter_frame = filter_frame,
281 static const AVFilterPad avfilter_vf_fps_outputs[] = {
284 .type = AVMEDIA_TYPE_VIDEO,
285 .rej_perms = AV_PERM_WRITE,
286 .request_frame = request_frame,
287 .config_props = config_props
292 AVFilter avfilter_vf_fps = {
294 .description = NULL_IF_CONFIG_SMALL("Force constant framerate"),
299 .priv_size = sizeof(FPSContext),
301 .inputs = avfilter_vf_fps_inputs,
302 .outputs = avfilter_vf_fps_outputs,
303 .priv_class = &fps_class,