lavfi: add error handling to start_frame().
[libav.git] / libavfilter / vf_setpts.c
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
22 /**
23 * @file
24 * video presentation timestamp (PTS) modification filter
25 */
26
27 /* #define DEBUG */
28
29 #include "libavutil/eval.h"
30 #include "libavutil/mathematics.h"
31 #include "avfilter.h"
32 #include "internal.h"
33 #include "video.h"
34
35 static const char *const var_names[] = {
36 "E", ///< Euler number
37 "INTERLACED", ///< tell if the current frame is interlaced
38 "N", ///< frame number (starting at zero)
39 "PHI", ///< golden ratio
40 "PI", ///< greek pi
41 "POS", ///< original position in the file of the frame
42 "PREV_INPTS", ///< previous input PTS
43 "PREV_OUTPTS", ///< previous output PTS
44 "PTS", ///< original pts in the file of the frame
45 "STARTPTS", ///< PTS at start of movie
46 "TB", ///< timebase
47 NULL
48 };
49
50 enum var_name {
51 VAR_E,
52 VAR_INTERLACED,
53 VAR_N,
54 VAR_PHI,
55 VAR_PI,
56 VAR_POS,
57 VAR_PREV_INPTS,
58 VAR_PREV_OUTPTS,
59 VAR_PTS,
60 VAR_STARTPTS,
61 VAR_TB,
62 VAR_VARS_NB
63 };
64
65 typedef struct {
66 AVExpr *expr;
67 double var_values[VAR_VARS_NB];
68 } SetPTSContext;
69
70 static av_cold int init(AVFilterContext *ctx, const char *args)
71 {
72 SetPTSContext *setpts = ctx->priv;
73 int ret;
74
75 if ((ret = av_expr_parse(&setpts->expr, args ? args : "PTS",
76 var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
77 av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
78 return ret;
79 }
80
81 setpts->var_values[VAR_E ] = M_E;
82 setpts->var_values[VAR_N ] = 0.0;
83 setpts->var_values[VAR_PHI ] = M_PHI;
84 setpts->var_values[VAR_PI ] = M_PI;
85 setpts->var_values[VAR_PREV_INPTS ] = NAN;
86 setpts->var_values[VAR_PREV_OUTPTS] = NAN;
87 setpts->var_values[VAR_STARTPTS ] = NAN;
88 return 0;
89 }
90
91 static int config_input(AVFilterLink *inlink)
92 {
93 SetPTSContext *setpts = inlink->dst->priv;
94
95 setpts->var_values[VAR_TB] = av_q2d(inlink->time_base);
96
97 av_log(inlink->src, AV_LOG_VERBOSE, "TB:%f\n", setpts->var_values[VAR_TB]);
98 return 0;
99 }
100
101 #define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
102 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
103
104 static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
105 {
106 SetPTSContext *setpts = inlink->dst->priv;
107 double d;
108 AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
109
110 if (!outpicref)
111 return AVERROR(ENOMEM);
112
113 if (isnan(setpts->var_values[VAR_STARTPTS]))
114 setpts->var_values[VAR_STARTPTS] = TS2D(inpicref->pts);
115
116 setpts->var_values[VAR_INTERLACED] = inpicref->video->interlaced;
117 setpts->var_values[VAR_PTS ] = TS2D(inpicref->pts);
118 setpts->var_values[VAR_POS ] = inpicref->pos == -1 ? NAN : inpicref->pos;
119
120 d = av_expr_eval(setpts->expr, setpts->var_values, NULL);
121 outpicref->pts = D2TS(d);
122
123 #ifdef DEBUG
124 av_log(inlink->dst, AV_LOG_DEBUG,
125 "n:%"PRId64" interlaced:%d pos:%"PRId64" pts:%"PRId64" t:%f -> pts:%"PRId64" t:%f\n",
126 (int64_t)setpts->var_values[VAR_N],
127 (int)setpts->var_values[VAR_INTERLACED],
128 inpicref ->pos,
129 inpicref ->pts, inpicref ->pts * av_q2d(inlink->time_base),
130 outpicref->pts, outpicref->pts * av_q2d(inlink->time_base));
131 #endif
132
133 setpts->var_values[VAR_N] += 1.0;
134 setpts->var_values[VAR_PREV_INPTS ] = TS2D(inpicref ->pts);
135 setpts->var_values[VAR_PREV_OUTPTS] = TS2D(outpicref->pts);
136 return ff_start_frame(inlink->dst->outputs[0], outpicref);
137 }
138
139 static av_cold void uninit(AVFilterContext *ctx)
140 {
141 SetPTSContext *setpts = ctx->priv;
142 av_expr_free(setpts->expr);
143 setpts->expr = NULL;
144 }
145
146 AVFilter avfilter_vf_setpts = {
147 .name = "setpts",
148 .description = NULL_IF_CONFIG_SMALL("Set PTS for the output video frame."),
149 .init = init,
150 .uninit = uninit,
151
152 .priv_size = sizeof(SetPTSContext),
153
154 .inputs = (const AVFilterPad[]) {{ .name = "default",
155 .type = AVMEDIA_TYPE_VIDEO,
156 .get_video_buffer = ff_null_get_video_buffer,
157 .config_props = config_input,
158 .start_frame = start_frame, },
159 { .name = NULL }},
160 .outputs = (const AVFilterPad[]) {{ .name = "default",
161 .type = AVMEDIA_TYPE_VIDEO, },
162 { .name = NULL}},
163 };