Implement settb filter.
[libav.git] / libavfilter / vf_settb.c
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214c0d42
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1/*
2 * Copyright (C) 2010 Stefano Sabatini
3 *
4 * This file is part of FFmpeg.
5 *
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.
10 *
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.
15 *
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
19 */
20
21/**
22 * @file
23 * Set timebase for the output link.
24 */
25
26#include "libavutil/avstring.h"
27#include "libavutil/eval.h"
28#include "libavutil/rational.h"
29#include "avfilter.h"
30#include "internal.h"
31
32static const char *var_names[] = {
33 "E",
34 "PHI",
35 "PI",
36 "AVTB", /* default timebase 1/AV_TIME_BASE */
37 "intb", /* input timebase */
38 NULL
39};
40
41enum var_name {
42 VAR_E,
43 VAR_PHI,
44 VAR_PI,
45 VAR_AVTB,
46 VAR_INTB,
47 VAR_VARS_NB
48};
49
50typedef struct {
51 char tb_expr[256];
52 double var_values[VAR_VARS_NB];
53} SetTBContext;
54
55static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
56{
57 SetTBContext *settb = ctx->priv;
58 av_strlcpy(settb->tb_expr, "intb", sizeof(settb->tb_expr));
59
60 if (args)
61 sscanf(args, "%255[^:]", settb->tb_expr);
62
63 return 0;
64}
65
66static int config_output_props(AVFilterLink *outlink)
67{
68 AVFilterContext *ctx = outlink->src;
69 SetTBContext *settb = ctx->priv;
70 AVFilterLink *inlink = ctx->inputs[0];
71 AVRational time_base;
72 int ret;
73 double res;
74
75 settb->var_values[VAR_E] = M_E;
76 settb->var_values[VAR_PHI] = M_PHI;
77 settb->var_values[VAR_PI] = M_PI;
78 settb->var_values[VAR_AVTB] = av_q2d(AV_TIME_BASE_Q);
79 settb->var_values[VAR_INTB] = av_q2d(inlink->time_base);
80
81 outlink->w = inlink->w;
82 outlink->h = inlink->h;
83
84 if ((ret = av_parse_and_eval_expr(&res, settb->tb_expr, var_names, settb->var_values,
85 NULL, NULL, NULL, NULL, NULL, 0, NULL)) < 0) {
86 av_log(ctx, AV_LOG_ERROR, "Invalid expression '%s' for timebase.\n", settb->tb_expr);
87 return ret;
88 }
89 time_base = av_d2q(res, INT_MAX);
90 if (time_base.num <= 0 || time_base.den <= 0) {
91 av_log(ctx, AV_LOG_ERROR,
92 "Invalid non-positive values for the timebase num:%d or den:%d.\n",
93 time_base.num, time_base.den);
94 return AVERROR(EINVAL);
95 }
96
97 outlink->time_base = time_base;
98 av_log(outlink->src, AV_LOG_INFO, "tb:%d/%d -> tb:%d/%d\n",
99 inlink ->time_base.num, inlink ->time_base.den,
100 outlink->time_base.num, outlink->time_base.den);
101
102 return 0;
103}
104
105static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
106{
107 AVFilterContext *ctx = inlink->dst;
108 AVFilterLink *outlink = ctx->outputs[0];
109 AVFilterBufferRef *picref2 = picref;
110
111 if (av_cmp_q(inlink->time_base, outlink->time_base)) {
112 picref2 = avfilter_ref_buffer(picref, ~0);
113 picref2->pts = av_rescale_q(picref->pts, inlink->time_base, outlink->time_base);
114 av_log(ctx, AV_LOG_DEBUG, "tb:%d/%d pts:%"PRId64" -> tb:%d/%d pts:%"PRId64"\n",
115 inlink ->time_base.num, inlink ->time_base.den, picref ->pts,
116 outlink->time_base.num, outlink->time_base.den, picref2->pts);
117 avfilter_unref_buffer(picref);
118 }
119
120 avfilter_start_frame(outlink, picref2);
121}
122
123AVFilter avfilter_vf_settb = {
124 .name = "settb",
125 .description = NULL_IF_CONFIG_SMALL("Set timebase for the output link."),
126 .init = init,
127
128 .priv_size = sizeof(SetTBContext),
129
130 .inputs = (AVFilterPad[]) {{ .name = "default",
131 .type = AVMEDIA_TYPE_VIDEO,
132 .get_video_buffer = avfilter_null_get_video_buffer,
133 .start_frame = start_frame,
134 .end_frame = avfilter_null_end_frame },
135 { .name = NULL }},
136
137 .outputs = (AVFilterPad[]) {{ .name = "default",
138 .type = AVMEDIA_TYPE_VIDEO,
139 .config_props = config_output_props, },
140 { .name = NULL}},
141};