49092588e14531264021574af39d8c913d368986
[libav.git] / libavfilter / vf_settb.c
1 /*
2 * Copyright (c) 2010 Stefano Sabatini
3 *
4 * This file is part of Libav.
5 *
6 * Libav 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 * Libav 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 Libav; 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/mathematics.h"
29 #include "libavutil/rational.h"
30 #include "avfilter.h"
31 #include "internal.h"
32 #include "video.h"
33
34 static const char *const var_names[] = {
35 "E",
36 "PHI",
37 "PI",
38 "AVTB", /* default timebase 1/AV_TIME_BASE */
39 "intb", /* input timebase */
40 NULL
41 };
42
43 enum var_name {
44 VAR_E,
45 VAR_PHI,
46 VAR_PI,
47 VAR_AVTB,
48 VAR_INTB,
49 VAR_VARS_NB
50 };
51
52 typedef struct {
53 char tb_expr[256];
54 double var_values[VAR_VARS_NB];
55 } SetTBContext;
56
57 static av_cold int init(AVFilterContext *ctx, const char *args)
58 {
59 SetTBContext *settb = ctx->priv;
60 av_strlcpy(settb->tb_expr, "intb", sizeof(settb->tb_expr));
61
62 if (args)
63 sscanf(args, "%255[^:]", settb->tb_expr);
64
65 return 0;
66 }
67
68 static int config_output_props(AVFilterLink *outlink)
69 {
70 AVFilterContext *ctx = outlink->src;
71 SetTBContext *settb = ctx->priv;
72 AVFilterLink *inlink = ctx->inputs[0];
73 AVRational time_base;
74 int ret;
75 double res;
76
77 settb->var_values[VAR_E] = M_E;
78 settb->var_values[VAR_PHI] = M_PHI;
79 settb->var_values[VAR_PI] = M_PI;
80 settb->var_values[VAR_AVTB] = av_q2d(AV_TIME_BASE_Q);
81 settb->var_values[VAR_INTB] = av_q2d(inlink->time_base);
82
83 outlink->w = inlink->w;
84 outlink->h = inlink->h;
85
86 if ((ret = av_expr_parse_and_eval(&res, settb->tb_expr, var_names, settb->var_values,
87 NULL, NULL, NULL, NULL, NULL, 0, NULL)) < 0) {
88 av_log(ctx, AV_LOG_ERROR, "Invalid expression '%s' for timebase.\n", settb->tb_expr);
89 return ret;
90 }
91 time_base = av_d2q(res, INT_MAX);
92 if (time_base.num <= 0 || time_base.den <= 0) {
93 av_log(ctx, AV_LOG_ERROR,
94 "Invalid non-positive values for the timebase num:%d or den:%d.\n",
95 time_base.num, time_base.den);
96 return AVERROR(EINVAL);
97 }
98
99 outlink->time_base = time_base;
100 av_log(outlink->src, AV_LOG_VERBOSE, "tb:%d/%d -> tb:%d/%d\n",
101 inlink ->time_base.num, inlink ->time_base.den,
102 outlink->time_base.num, outlink->time_base.den);
103
104 return 0;
105 }
106
107 static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
108 {
109 AVFilterContext *ctx = inlink->dst;
110 AVFilterLink *outlink = ctx->outputs[0];
111
112 if (av_cmp_q(inlink->time_base, outlink->time_base)) {
113 int64_t orig_pts = picref->pts;
114 picref->pts = av_rescale_q(picref->pts, inlink->time_base, outlink->time_base);
115 av_log(ctx, AV_LOG_DEBUG, "tb:%d/%d pts:%"PRId64" -> tb:%d/%d pts:%"PRId64"\n",
116 inlink ->time_base.num, inlink ->time_base.den, orig_pts,
117 outlink->time_base.num, outlink->time_base.den, picref->pts);
118 }
119 inlink->cur_buf = NULL;
120
121 ff_start_frame(outlink, picref);
122 }
123
124 AVFilter avfilter_vf_settb = {
125 .name = "settb",
126 .description = NULL_IF_CONFIG_SMALL("Set timebase for the output link."),
127 .init = init,
128
129 .priv_size = sizeof(SetTBContext),
130
131 .inputs = (const AVFilterPad[]) {{ .name = "default",
132 .type = AVMEDIA_TYPE_VIDEO,
133 .get_video_buffer = ff_null_get_video_buffer,
134 .start_frame = start_frame,
135 .end_frame = ff_null_end_frame },
136 { .name = NULL }},
137
138 .outputs = (const AVFilterPad[]) {{ .name = "default",
139 .type = AVMEDIA_TYPE_VIDEO,
140 .config_props = config_output_props, },
141 { .name = NULL}},
142 };