vf_settb.c
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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 
26 #include <inttypes.h>
27 #include <stdio.h>
28 
29 #include "libavutil/avstring.h"
30 #include "libavutil/eval.h"
31 #include "libavutil/internal.h"
32 #include "libavutil/mathematics.h"
33 #include "libavutil/rational.h"
34 #include "avfilter.h"
35 #include "internal.h"
36 #include "video.h"
37 
38 static const char *const var_names[] = {
39  "E",
40  "PHI",
41  "PI",
42  "AVTB", /* default timebase 1/AV_TIME_BASE */
43  "intb", /* input timebase */
44  NULL
45 };
46 
47 enum var_name {
54 };
55 
56 typedef struct {
57  char tb_expr[256];
58  double var_values[VAR_VARS_NB];
59 } SetTBContext;
60 
61 static av_cold int init(AVFilterContext *ctx, const char *args)
62 {
63  SetTBContext *settb = ctx->priv;
64  av_strlcpy(settb->tb_expr, "intb", sizeof(settb->tb_expr));
65 
66  if (args)
67  sscanf(args, "%255[^:]", settb->tb_expr);
68 
69  return 0;
70 }
71 
72 static int config_output_props(AVFilterLink *outlink)
73 {
74  AVFilterContext *ctx = outlink->src;
75  SetTBContext *settb = ctx->priv;
76  AVFilterLink *inlink = ctx->inputs[0];
77  AVRational time_base;
78  int ret;
79  double res;
80 
81  settb->var_values[VAR_E] = M_E;
82  settb->var_values[VAR_PHI] = M_PHI;
83  settb->var_values[VAR_PI] = M_PI;
85  settb->var_values[VAR_INTB] = av_q2d(inlink->time_base);
86 
87  outlink->w = inlink->w;
88  outlink->h = inlink->h;
89 
90  if ((ret = av_expr_parse_and_eval(&res, settb->tb_expr, var_names, settb->var_values,
91  NULL, NULL, NULL, NULL, NULL, 0, NULL)) < 0) {
92  av_log(ctx, AV_LOG_ERROR, "Invalid expression '%s' for timebase.\n", settb->tb_expr);
93  return ret;
94  }
95  time_base = av_d2q(res, INT_MAX);
96  if (time_base.num <= 0 || time_base.den <= 0) {
97  av_log(ctx, AV_LOG_ERROR,
98  "Invalid non-positive values for the timebase num:%d or den:%d.\n",
99  time_base.num, time_base.den);
100  return AVERROR(EINVAL);
101  }
102 
103  outlink->time_base = time_base;
104  av_log(outlink->src, AV_LOG_VERBOSE, "tb:%d/%d -> tb:%d/%d\n",
105  inlink ->time_base.num, inlink ->time_base.den,
106  outlink->time_base.num, outlink->time_base.den);
107 
108  return 0;
109 }
110 
111 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *frame)
112 {
113  AVFilterContext *ctx = inlink->dst;
114  AVFilterLink *outlink = ctx->outputs[0];
115 
116  if (av_cmp_q(inlink->time_base, outlink->time_base)) {
117  int64_t orig_pts = frame->pts;
118  frame->pts = av_rescale_q(frame->pts, inlink->time_base, outlink->time_base);
119  av_log(ctx, AV_LOG_DEBUG, "tb:%d/%d pts:%"PRId64" -> tb:%d/%d pts:%"PRId64"\n",
120  inlink ->time_base.num, inlink ->time_base.den, orig_pts,
121  outlink->time_base.num, outlink->time_base.den, frame->pts);
122  }
123 
124  return ff_filter_frame(outlink, frame);
125 }
126 
128  {
129  .name = "default",
130  .type = AVMEDIA_TYPE_VIDEO,
131  .get_video_buffer = ff_null_get_video_buffer,
132  .filter_frame = filter_frame,
133  },
134  { NULL }
135 };
136 
138  {
139  .name = "default",
140  .type = AVMEDIA_TYPE_VIDEO,
141  .config_props = config_output_props,
142  },
143  { NULL }
144 };
145 
147  .name = "settb",
148  .description = NULL_IF_CONFIG_SMALL("Set timebase for the output link."),
149  .init = init,
150 
151  .priv_size = sizeof(SetTBContext),
152 
153  .inputs = avfilter_vf_settb_inputs,
154 
155  .outputs = avfilter_vf_settb_outputs,
156 };