2 * Copyright (c) 2010 Stefano Sabatini
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * Set timebase for the output link.
26 #include "libavutil/avstring.h"
27 #include "libavutil/eval.h"
28 #include "libavutil/mathematics.h"
29 #include "libavutil/rational.h"
33 static const char *const var_names[] = {
34 "AVTB", /* default timebase 1/AV_TIME_BASE */
35 "intb", /* input timebase */
47 double var_values[VAR_VARS_NB];
50 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
52 SetTBContext *settb = ctx->priv;
53 av_strlcpy(settb->tb_expr, "intb", sizeof(settb->tb_expr));
56 sscanf(args, "%255[^:]", settb->tb_expr);
61 static int config_output_props(AVFilterLink *outlink)
63 AVFilterContext *ctx = outlink->src;
64 SetTBContext *settb = ctx->priv;
65 AVFilterLink *inlink = ctx->inputs[0];
70 settb->var_values[VAR_AVTB] = av_q2d(AV_TIME_BASE_Q);
71 settb->var_values[VAR_INTB] = av_q2d(inlink->time_base);
73 outlink->w = inlink->w;
74 outlink->h = inlink->h;
76 if ((ret = av_expr_parse_and_eval(&res, settb->tb_expr, var_names, settb->var_values,
77 NULL, NULL, NULL, NULL, NULL, 0, NULL)) < 0) {
78 av_log(ctx, AV_LOG_ERROR, "Invalid expression '%s' for timebase.\n", settb->tb_expr);
81 time_base = av_d2q(res, INT_MAX);
82 if (time_base.num <= 0 || time_base.den <= 0) {
83 av_log(ctx, AV_LOG_ERROR,
84 "Invalid non-positive values for the timebase num:%d or den:%d.\n",
85 time_base.num, time_base.den);
86 return AVERROR(EINVAL);
89 outlink->time_base = time_base;
90 av_log(outlink->src, AV_LOG_INFO, "tb:%d/%d -> tb:%d/%d\n",
91 inlink ->time_base.num, inlink ->time_base.den,
92 outlink->time_base.num, outlink->time_base.den);
97 static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
99 AVFilterContext *ctx = inlink->dst;
100 AVFilterLink *outlink = ctx->outputs[0];
101 AVFilterBufferRef *picref2 = picref;
103 if (av_cmp_q(inlink->time_base, outlink->time_base)) {
104 picref2 = avfilter_ref_buffer(picref, ~0);
105 picref2->pts = av_rescale_q(picref->pts, inlink->time_base, outlink->time_base);
106 av_log(ctx, AV_LOG_DEBUG, "tb:%d/%d pts:%"PRId64" -> tb:%d/%d pts:%"PRId64"\n",
107 inlink ->time_base.num, inlink ->time_base.den, picref ->pts,
108 outlink->time_base.num, outlink->time_base.den, picref2->pts);
109 avfilter_unref_buffer(picref);
112 avfilter_start_frame(outlink, picref2);
115 AVFilter avfilter_vf_settb = {
117 .description = NULL_IF_CONFIG_SMALL("Set timebase for the output link."),
120 .priv_size = sizeof(SetTBContext),
122 .inputs = (const AVFilterPad[]) {{ .name = "default",
123 .type = AVMEDIA_TYPE_VIDEO,
124 .get_video_buffer = avfilter_null_get_video_buffer,
125 .start_frame = start_frame,
126 .end_frame = avfilter_null_end_frame },
129 .outputs = (const AVFilterPad[]) {{ .name = "default",
130 .type = AVMEDIA_TYPE_VIDEO,
131 .config_props = config_output_props, },