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 options[] = {
59 { "fps", "A string describing desired output framerate", OFFSET(fps), AV_OPT_TYPE_STRING, { .str = "25" }, .flags = V },
63 static const AVClass class = {
65 .item_name = av_default_item_name,
67 .version = LIBAVUTIL_VERSION_INT,
68 .category = AV_CLASS_CATEGORY_FILTER,
71 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
73 FPSContext *s = ctx->priv;
77 av_opt_set_defaults(s);
79 if ((ret = av_set_options_string(s, args, "=", ":")) < 0) {
80 av_log(ctx, AV_LOG_ERROR, "Error parsing the options string %s.\n",
85 if ((ret = av_parse_video_rate(&s->framerate, s->fps)) < 0) {
86 av_log(ctx, AV_LOG_ERROR, "Error parsing framerate %s.\n", s->fps);
91 if (!(s->fifo = av_fifo_alloc(2*sizeof(AVFilterBufferRef*))))
92 return AVERROR(ENOMEM);
94 av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);
98 static void flush_fifo(AVFifoBuffer *fifo)
100 while (av_fifo_size(fifo)) {
101 AVFilterBufferRef *tmp;
102 av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);
103 avfilter_unref_buffer(tmp);
107 static av_cold void uninit(AVFilterContext *ctx)
109 FPSContext *s = ctx->priv;
112 av_fifo_free(s->fifo);
115 av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
116 "%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);
119 static int config_props(AVFilterLink* link)
121 FPSContext *s = link->src->priv;
123 link->time_base = (AVRational){ s->framerate.den, s->framerate.num };
124 link->frame_rate= s->framerate;
125 link->w = link->src->inputs[0]->w;
126 link->h = link->src->inputs[0]->h;
127 s->pts = AV_NOPTS_VALUE;
132 static int request_frame(AVFilterLink *outlink)
134 AVFilterContext *ctx = outlink->src;
135 FPSContext *s = ctx->priv;
136 int frames_out = s->frames_out;
139 while (ret >= 0 && s->frames_out == frames_out)
140 ret = ff_request_frame(ctx->inputs[0]);
143 if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {
145 for (i = 0; av_fifo_size(s->fifo); i++) {
146 AVFilterBufferRef *buf;
148 av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);
149 buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,
150 outlink->time_base) + s->frames_out;
152 ff_start_frame(outlink, buf);
153 ff_draw_slice(outlink, 0, outlink->h, 1);
154 ff_end_frame(outlink);
163 static int write_to_fifo(AVFifoBuffer *fifo, AVFilterBufferRef *buf)
167 if (!av_fifo_space(fifo) &&
168 (ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo))))
171 av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);
175 static void end_frame(AVFilterLink *inlink)
177 AVFilterContext *ctx = inlink->dst;
178 FPSContext *s = ctx->priv;
179 AVFilterLink *outlink = ctx->outputs[0];
180 AVFilterBufferRef *buf = inlink->cur_buf;
185 /* discard frames until we get the first timestamp */
186 if (s->pts == AV_NOPTS_VALUE) {
187 if (buf->pts != AV_NOPTS_VALUE) {
188 write_to_fifo(s->fifo, buf);
189 s->first_pts = s->pts = buf->pts;
191 av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "
193 avfilter_unref_buffer(buf);
199 /* now wait for the next timestamp */
200 if (buf->pts == AV_NOPTS_VALUE) {
201 write_to_fifo(s->fifo, buf);
205 /* number of output frames */
206 delta = av_rescale_q(buf->pts - s->pts, inlink->time_base,
210 /* drop the frame and everything buffered except the first */
211 AVFilterBufferRef *tmp;
212 int drop = av_fifo_size(s->fifo)/sizeof(AVFilterBufferRef*);
214 av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);
217 av_fifo_generic_read(s->fifo, &tmp, sizeof(tmp), NULL);
219 write_to_fifo(s->fifo, tmp);
221 avfilter_unref_buffer(buf);
225 /* can output >= 1 frames */
226 for (i = 0; i < delta; i++) {
227 AVFilterBufferRef *buf_out;
228 av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);
230 /* duplicate the frame if needed */
231 if (!av_fifo_size(s->fifo) && i < delta - 1) {
232 av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");
233 write_to_fifo(s->fifo, avfilter_ref_buffer(buf_out, AV_PERM_READ));
237 buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,
238 outlink->time_base) + s->frames_out;
240 ff_start_frame(outlink, buf_out);
241 ff_draw_slice(outlink, 0, outlink->h, 1);
242 ff_end_frame(outlink);
247 write_to_fifo(s->fifo, buf);
248 s->pts = s->first_pts + av_rescale_q(s->frames_out, outlink->time_base, inlink->time_base);
251 static void null_start_frame(AVFilterLink *link, AVFilterBufferRef *buf)
255 static void null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
259 AVFilter avfilter_vf_fps = {
261 .description = NULL_IF_CONFIG_SMALL("Force constant framerate"),
266 .priv_size = sizeof(FPSContext),
268 .inputs = (AVFilterPad[]) {{ .name = "default",
269 .type = AVMEDIA_TYPE_VIDEO,
270 .start_frame = null_start_frame,
271 .draw_slice = null_draw_slice,
272 .end_frame = end_frame, },
274 .outputs = (AVFilterPad[]) {{ .name = "default",
275 .type = AVMEDIA_TYPE_VIDEO,
276 .request_frame = request_frame,
277 .config_props = config_props},