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f_settb.c
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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 <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/opt.h"
34 #include "libavutil/rational.h"
35 #include "avfilter.h"
36 #include "internal.h"
37 #include "audio.h"
38 #include "video.h"
39 
40 static const char *const var_names[] = {
41  "AVTB", /* default timebase 1/AV_TIME_BASE */
42  "intb", /* input timebase */
43  "sr", /* sample rate */
44  NULL
45 };
46 
47 enum var_name {
52 };
53 
54 typedef struct {
55  const AVClass *class;
56  char *tb_expr;
57  double var_values[VAR_VARS_NB];
58 } SetTBContext;
59 
60 #define OFFSET(x) offsetof(SetTBContext, x)
61 #define DEFINE_OPTIONS(filt_name, filt_type) \
62 static const AVOption filt_name##_options[] = { \
63  { "expr", "set expression determining the output timebase", OFFSET(tb_expr), AV_OPT_TYPE_STRING, {.str="intb"}, \
64  .flags=AV_OPT_FLAG_##filt_type##_PARAM|AV_OPT_FLAG_FILTERING_PARAM }, \
65  { "tb", "set expression determining the output timebase", OFFSET(tb_expr), AV_OPT_TYPE_STRING, {.str="intb"}, \
66  .flags=AV_OPT_FLAG_##filt_type##_PARAM|AV_OPT_FLAG_FILTERING_PARAM }, \
67  { NULL } \
68 }
69 
70 static int config_output_props(AVFilterLink *outlink)
71 {
72  AVFilterContext *ctx = outlink->src;
73  SetTBContext *settb = ctx->priv;
74  AVFilterLink *inlink = ctx->inputs[0];
75  AVRational time_base;
76  int ret;
77  double res;
78 
80  settb->var_values[VAR_INTB] = av_q2d(inlink->time_base);
81  settb->var_values[VAR_SR] = inlink->sample_rate;
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 int filter_frame(AVFilterLink *inlink, AVFrame *frame)
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 = frame->pts;
114  frame->pts = av_rescale_q(frame->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, frame->pts);
118  }
119 
120  return ff_filter_frame(outlink, frame);
121 }
122 
123 #if CONFIG_SETTB_FILTER
124 
125 DEFINE_OPTIONS(settb, VIDEO);
126 AVFILTER_DEFINE_CLASS(settb);
127 
128 static const AVFilterPad avfilter_vf_settb_inputs[] = {
129  {
130  .name = "default",
131  .type = AVMEDIA_TYPE_VIDEO,
132  .get_video_buffer = ff_null_get_video_buffer,
133  .filter_frame = filter_frame,
134  },
135  { NULL }
136 };
137 
138 static const AVFilterPad avfilter_vf_settb_outputs[] = {
139  {
140  .name = "default",
141  .type = AVMEDIA_TYPE_VIDEO,
142  .config_props = config_output_props,
143  },
144  { NULL }
145 };
146 
147 AVFilter avfilter_vf_settb = {
148  .name = "settb",
149  .description = NULL_IF_CONFIG_SMALL("Set timebase for the video output link."),
150 
151  .priv_size = sizeof(SetTBContext),
152  .priv_class = &settb_class,
153 
154  .inputs = avfilter_vf_settb_inputs,
155  .outputs = avfilter_vf_settb_outputs,
156 };
157 #endif
158 
159 #if CONFIG_ASETTB_FILTER
160 
161 DEFINE_OPTIONS(asettb, AUDIO);
162 AVFILTER_DEFINE_CLASS(asettb);
163 
164 static const AVFilterPad avfilter_af_asettb_inputs[] = {
165  {
166  .name = "default",
167  .type = AVMEDIA_TYPE_AUDIO,
168  .get_audio_buffer = ff_null_get_audio_buffer,
169  .filter_frame = filter_frame,
170  },
171  { NULL }
172 };
173 
174 static const AVFilterPad avfilter_af_asettb_outputs[] = {
175  {
176  .name = "default",
177  .type = AVMEDIA_TYPE_AUDIO,
178  .config_props = config_output_props,
179  },
180  { NULL }
181 };
182 
183 AVFilter avfilter_af_asettb = {
184  .name = "asettb",
185  .description = NULL_IF_CONFIG_SMALL("Set timebase for the audio output link."),
186 
187  .priv_size = sizeof(SetTBContext),
188  .inputs = avfilter_af_asettb_inputs,
189  .outputs = avfilter_af_asettb_outputs,
190  .priv_class = &asettb_class,
191 };
192 #endif