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/fifo.h"
29 #include "libavutil/mathematics.h"
30 #include "libavutil/opt.h"
31 #include "libavutil/parseutils.h"
37 typedef struct FPSContext {
40 AVFifoBuffer *fifo; ///< store frames until we get two successive timestamps
42 /* timestamps in input timebase */
43 int64_t first_pts; ///< pts of the first frame that arrived on this filter
44 int64_t pts; ///< pts of the first frame currently in the fifo
46 AVRational framerate; ///< target framerate
47 char *fps; ///< a string describing target framerate
50 int frames_in; ///< number of frames on input
51 int frames_out; ///< number of frames on output
52 int dup; ///< number of frames duplicated
53 int drop; ///< number of framed dropped
56 #define OFFSET(x) offsetof(FPSContext, x)
57 #define V AV_OPT_FLAG_VIDEO_PARAM
58 static const AVOption fps_options[] = {
59 { "fps", "A string describing desired output framerate", OFFSET(fps), AV_OPT_TYPE_STRING, { .str = "25" }, .flags = V },
63 AVFILTER_DEFINE_CLASS(fps);
65 static av_cold int init(AVFilterContext *ctx, const char *args)
67 FPSContext *s = ctx->priv;
70 s->class = &fps_class;
71 av_opt_set_defaults(s);
73 if ((ret = av_set_options_string(s, args, "=", ":")) < 0) {
74 av_log(ctx, AV_LOG_ERROR, "Error parsing the options string %s.\n",
79 if ((ret = av_parse_video_rate(&s->framerate, s->fps)) < 0) {
80 av_log(ctx, AV_LOG_ERROR, "Error parsing framerate %s.\n", s->fps);
85 if (!(s->fifo = av_fifo_alloc(2*sizeof(AVFilterBufferRef*))))
86 return AVERROR(ENOMEM);
88 av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);
92 static void flush_fifo(AVFifoBuffer *fifo)
94 while (av_fifo_size(fifo)) {
95 AVFilterBufferRef *tmp;
96 av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);
97 avfilter_unref_buffer(tmp);
101 static av_cold void uninit(AVFilterContext *ctx)
103 FPSContext *s = ctx->priv;
106 av_fifo_free(s->fifo);
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);
113 static int config_props(AVFilterLink* link)
115 FPSContext *s = link->src->priv;
117 link->time_base = (AVRational){ s->framerate.den, s->framerate.num };
118 link->frame_rate= s->framerate;
119 link->w = link->src->inputs[0]->w;
120 link->h = link->src->inputs[0]->h;
121 s->pts = AV_NOPTS_VALUE;
126 static int request_frame(AVFilterLink *outlink)
128 AVFilterContext *ctx = outlink->src;
129 FPSContext *s = ctx->priv;
130 int frames_out = s->frames_out;
133 while (ret >= 0 && s->frames_out == frames_out)
134 ret = ff_request_frame(ctx->inputs[0]);
137 if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {
139 for (i = 0; av_fifo_size(s->fifo); i++) {
140 AVFilterBufferRef *buf;
142 av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);
143 buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,
144 outlink->time_base) + s->frames_out;
146 ff_start_frame(outlink, buf);
147 ff_draw_slice(outlink, 0, outlink->h, 1);
148 ff_end_frame(outlink);
157 static int write_to_fifo(AVFifoBuffer *fifo, AVFilterBufferRef *buf)
161 if (!av_fifo_space(fifo) &&
162 (ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo))))
165 av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);
169 static void end_frame(AVFilterLink *inlink)
171 AVFilterContext *ctx = inlink->dst;
172 FPSContext *s = ctx->priv;
173 AVFilterLink *outlink = ctx->outputs[0];
174 AVFilterBufferRef *buf = inlink->cur_buf;
179 /* discard frames until we get the first timestamp */
180 if (s->pts == AV_NOPTS_VALUE) {
181 if (buf->pts != AV_NOPTS_VALUE) {
182 write_to_fifo(s->fifo, buf);
183 s->first_pts = s->pts = buf->pts;
185 av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "
187 avfilter_unref_buffer(buf);
193 /* now wait for the next timestamp */
194 if (buf->pts == AV_NOPTS_VALUE) {
195 write_to_fifo(s->fifo, buf);
199 /* number of output frames */
200 delta = av_rescale_q(buf->pts - s->pts, inlink->time_base,
204 /* drop the frame and everything buffered except the first */
205 AVFilterBufferRef *tmp;
206 int drop = av_fifo_size(s->fifo)/sizeof(AVFilterBufferRef*);
208 av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);
211 av_fifo_generic_read(s->fifo, &tmp, sizeof(tmp), NULL);
213 write_to_fifo(s->fifo, tmp);
215 avfilter_unref_buffer(buf);
219 /* can output >= 1 frames */
220 for (i = 0; i < delta; i++) {
221 AVFilterBufferRef *buf_out;
222 av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);
224 /* duplicate the frame if needed */
225 if (!av_fifo_size(s->fifo) && i < delta - 1) {
226 av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");
227 write_to_fifo(s->fifo, avfilter_ref_buffer(buf_out, AV_PERM_READ));
231 buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,
232 outlink->time_base) + s->frames_out;
234 ff_start_frame(outlink, buf_out);
235 ff_draw_slice(outlink, 0, outlink->h, 1);
236 ff_end_frame(outlink);
241 write_to_fifo(s->fifo, buf);
242 s->pts = s->first_pts + av_rescale_q(s->frames_out, outlink->time_base, inlink->time_base);
245 static void null_start_frame(AVFilterLink *link, AVFilterBufferRef *buf)
249 static void null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
253 AVFilter avfilter_vf_fps = {
255 .description = NULL_IF_CONFIG_SMALL("Force constant framerate"),
260 .priv_size = sizeof(FPSContext),
262 .inputs = (AVFilterPad[]) {{ .name = "default",
263 .type = AVMEDIA_TYPE_VIDEO,
264 .start_frame = null_start_frame,
265 .draw_slice = null_draw_slice,
266 .end_frame = end_frame, },
268 .outputs = (AVFilterPad[]) {{ .name = "default",
269 .type = AVMEDIA_TYPE_VIDEO,
270 .request_frame = request_frame,
271 .config_props = config_props},