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"
35 typedef struct FPSContext {
38 AVFifoBuffer *fifo; ///< store frames until we get two successive timestamps
40 /* timestamps in input timebase */
41 int64_t first_pts; ///< pts of the first frame that arrived on this filter
42 int64_t pts; ///< pts of the first frame currently in the fifo
44 AVRational framerate; ///< target framerate
45 char *fps; ///< a string describing target framerate
48 int frames_in; ///< number of frames on input
49 int frames_out; ///< number of frames on output
50 int dup; ///< number of frames duplicated
51 int drop; ///< number of framed dropped
54 #define OFFSET(x) offsetof(FPSContext, x)
55 #define V AV_OPT_FLAG_VIDEO_PARAM
56 static const AVOption options[] = {
57 { "fps", "A string describing desired output framerate", OFFSET(fps), AV_OPT_TYPE_STRING, { .str = "25" }, .flags = V },
61 static const AVClass class = {
62 .class_name = "FPS filter",
63 .item_name = av_default_item_name,
65 .version = LIBAVUTIL_VERSION_INT,
68 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
70 FPSContext *s = ctx->priv;
74 av_opt_set_defaults(s);
76 if ((ret = av_set_options_string(s, args, "=", ":")) < 0) {
77 av_log(ctx, AV_LOG_ERROR, "Error parsing the options string %s.\n",
82 if ((ret = av_parse_video_rate(&s->framerate, s->fps)) < 0) {
83 av_log(ctx, AV_LOG_ERROR, "Error parsing framerate %s.\n", s->fps);
88 if (!(s->fifo = av_fifo_alloc(2*sizeof(AVFilterBufferRef*))))
89 return AVERROR(ENOMEM);
91 av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);
95 static void flush_fifo(AVFifoBuffer *fifo)
97 while (av_fifo_size(fifo)) {
98 AVFilterBufferRef *tmp;
99 av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);
100 avfilter_unref_buffer(tmp);
104 static av_cold void uninit(AVFilterContext *ctx)
106 FPSContext *s = ctx->priv;
109 av_fifo_free(s->fifo);
112 av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
113 "%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);
116 static int config_props(AVFilterLink* link)
118 FPSContext *s = link->src->priv;
120 link->time_base = (AVRational){ s->framerate.den, s->framerate.num };
121 link->w = link->src->inputs[0]->w;
122 link->h = link->src->inputs[0]->h;
123 s->pts = AV_NOPTS_VALUE;
128 static int request_frame(AVFilterLink *outlink)
130 AVFilterContext *ctx = outlink->src;
131 FPSContext *s = ctx->priv;
132 int frames_out = s->frames_out;
135 while (ret >= 0 && s->frames_out == frames_out)
136 ret = avfilter_request_frame(ctx->inputs[0]);
139 if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {
141 for (i = 0; av_fifo_size(s->fifo); i++) {
142 AVFilterBufferRef *buf;
144 av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);
145 buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,
146 outlink->time_base) + s->frames_out;
148 avfilter_start_frame(outlink, buf);
149 avfilter_draw_slice(outlink, 0, outlink->h, 1);
150 avfilter_end_frame(outlink);
159 static int write_to_fifo(AVFifoBuffer *fifo, AVFilterBufferRef *buf)
163 if (!av_fifo_space(fifo) &&
164 (ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo))))
167 av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);
171 static void end_frame(AVFilterLink *inlink)
173 AVFilterContext *ctx = inlink->dst;
174 FPSContext *s = ctx->priv;
175 AVFilterLink *outlink = ctx->outputs[0];
176 AVFilterBufferRef *buf = inlink->cur_buf;
181 /* discard frames until we get the first timestamp */
182 if (s->pts == AV_NOPTS_VALUE) {
183 if (buf->pts != AV_NOPTS_VALUE) {
184 write_to_fifo(s->fifo, buf);
185 s->first_pts = s->pts = buf->pts;
187 av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "
189 avfilter_unref_buffer(buf);
195 /* now wait for the next timestamp */
196 if (buf->pts == AV_NOPTS_VALUE) {
197 write_to_fifo(s->fifo, buf);
201 /* number of output frames */
202 delta = av_rescale_q(buf->pts - s->pts, inlink->time_base,
206 /* drop the frame and everything buffered except the first */
207 AVFilterBufferRef *tmp;
208 int drop = av_fifo_size(s->fifo)/sizeof(AVFilterBufferRef*);
210 av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);
213 av_fifo_generic_read(s->fifo, &tmp, sizeof(tmp), NULL);
215 write_to_fifo(s->fifo, tmp);
217 avfilter_unref_buffer(buf);
221 /* can output >= 1 frames */
222 for (i = 0; i < delta; i++) {
223 AVFilterBufferRef *buf_out;
224 av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);
226 /* duplicate the frame if needed */
227 if (!av_fifo_size(s->fifo) && i < delta - 1) {
228 av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");
229 write_to_fifo(s->fifo, avfilter_ref_buffer(buf_out, AV_PERM_READ));
233 buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,
234 outlink->time_base) + s->frames_out;
236 avfilter_start_frame(outlink, buf_out);
237 avfilter_draw_slice(outlink, 0, outlink->h, 1);
238 avfilter_end_frame(outlink);
243 write_to_fifo(s->fifo, buf);
244 s->pts = s->first_pts + av_rescale_q(s->frames_out, outlink->time_base, inlink->time_base);
247 static void null_start_frame(AVFilterLink *link, AVFilterBufferRef *buf)
251 static void null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
255 AVFilter avfilter_vf_fps = {
257 .description = NULL_IF_CONFIG_SMALL("Force constant framerate"),
262 .priv_size = sizeof(FPSContext),
264 .inputs = (AVFilterPad[]) {{ .name = "default",
265 .type = AVMEDIA_TYPE_VIDEO,
266 .start_frame = null_start_frame,
267 .draw_slice = null_draw_slice,
268 .end_frame = end_frame, },
270 .outputs = (AVFilterPad[]) {{ .name = "default",
271 .type = AVMEDIA_TYPE_VIDEO,
272 .request_frame = request_frame,
273 .config_props = config_props},