vf_setpts.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2010 Stefano Sabatini
3  * Copyright (c) 2008 Victor Paesa
4  *
5  * This file is part of Libav.
6  *
7  * Libav is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * Libav is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
27 /* #define DEBUG */
28 
29 #include "libavutil/eval.h"
30 #include "libavutil/internal.h"
31 #include "libavutil/mathematics.h"
32 #include "avfilter.h"
33 #include "internal.h"
34 #include "video.h"
35 
36 static const char *const var_names[] = {
37  "E",
38  "INTERLACED",
39  "N",
40  "PHI",
41  "PI",
42  "POS",
43  "PREV_INPTS",
44  "PREV_OUTPTS",
45  "PTS",
46  "STARTPTS",
47  "TB",
48  NULL
49 };
50 
51 enum var_name {
64 };
65 
66 typedef struct {
68  double var_values[VAR_VARS_NB];
70 
71 static av_cold int init(AVFilterContext *ctx, const char *args)
72 {
73  SetPTSContext *setpts = ctx->priv;
74  int ret;
75 
76  if ((ret = av_expr_parse(&setpts->expr, args ? args : "PTS",
77  var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
78  av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
79  return ret;
80  }
81 
82  setpts->var_values[VAR_E ] = M_E;
83  setpts->var_values[VAR_N ] = 0.0;
84  setpts->var_values[VAR_PHI ] = M_PHI;
85  setpts->var_values[VAR_PI ] = M_PI;
86  setpts->var_values[VAR_PREV_INPTS ] = NAN;
87  setpts->var_values[VAR_PREV_OUTPTS] = NAN;
88  setpts->var_values[VAR_STARTPTS ] = NAN;
89  return 0;
90 }
91 
92 static int config_input(AVFilterLink *inlink)
93 {
94  SetPTSContext *setpts = inlink->dst->priv;
95 
96  setpts->var_values[VAR_TB] = av_q2d(inlink->time_base);
97 
98  av_log(inlink->src, AV_LOG_VERBOSE, "TB:%f\n", setpts->var_values[VAR_TB]);
99  return 0;
100 }
101 
102 #define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
103 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
104 
105 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *frame)
106 {
107  SetPTSContext *setpts = inlink->dst->priv;
108  int64_t in_pts = frame->pts;
109  double d;
110 
111  if (isnan(setpts->var_values[VAR_STARTPTS]))
112  setpts->var_values[VAR_STARTPTS] = TS2D(frame->pts);
113 
114  setpts->var_values[VAR_INTERLACED] = frame->video->interlaced;
115  setpts->var_values[VAR_PTS ] = TS2D(frame->pts);
116  setpts->var_values[VAR_POS ] = frame->pos == -1 ? NAN : frame->pos;
117 
118  d = av_expr_eval(setpts->expr, setpts->var_values, NULL);
119  frame->pts = D2TS(d);
120 
121 #ifdef DEBUG
122  av_log(inlink->dst, AV_LOG_DEBUG,
123  "n:%"PRId64" interlaced:%d pos:%"PRId64" pts:%"PRId64" t:%f -> pts:%"PRId64" t:%f\n",
124  (int64_t)setpts->var_values[VAR_N],
125  (int)setpts->var_values[VAR_INTERLACED],
126  frame->pos, in_pts, in_pts * av_q2d(inlink->time_base),
127  frame->pts, frame->pts * av_q2d(inlink->time_base));
128 #endif
129 
130 
131  setpts->var_values[VAR_N] += 1.0;
132  setpts->var_values[VAR_PREV_INPTS ] = TS2D(in_pts);
133  setpts->var_values[VAR_PREV_OUTPTS] = TS2D(frame->pts);
134  return ff_filter_frame(inlink->dst->outputs[0], frame);
135 }
136 
137 static av_cold void uninit(AVFilterContext *ctx)
138 {
139  SetPTSContext *setpts = ctx->priv;
140  av_expr_free(setpts->expr);
141  setpts->expr = NULL;
142 }
143 
145  {
146  .name = "default",
147  .type = AVMEDIA_TYPE_VIDEO,
148  .get_video_buffer = ff_null_get_video_buffer,
149  .config_props = config_input,
150  .filter_frame = filter_frame,
151  },
152  { NULL }
153 };
154 
156  {
157  .name = "default",
158  .type = AVMEDIA_TYPE_VIDEO,
159  },
160  { NULL }
161 };
162 
164  .name = "setpts",
165  .description = NULL_IF_CONFIG_SMALL("Set PTS for the output video frame."),
166  .init = init,
167  .uninit = uninit,
168 
169  .priv_size = sizeof(SetPTSContext),
170 
171  .inputs = avfilter_vf_setpts_inputs,
172  .outputs = avfilter_vf_setpts_outputs,
173 };