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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/rational.h"
34 #include "avfilter.h"
35 #include "internal.h"
36 #include "audio.h"
37 #include "video.h"
38 
39 static const char *const var_names[] = {
40  "AVTB", /* default timebase 1/AV_TIME_BASE */
41  "intb", /* input timebase */
42  "sr", /* sample rate */
43  NULL
44 };
45 
46 enum var_name {
51 };
52 
53 typedef struct {
54  char tb_expr[256];
55  double var_values[VAR_VARS_NB];
56 } SetTBContext;
57 
58 static av_cold int init(AVFilterContext *ctx, const char *args)
59 {
60  SetTBContext *settb = ctx->priv;
61  av_strlcpy(settb->tb_expr, "intb", sizeof(settb->tb_expr));
62 
63  if (args)
64  sscanf(args, "%255[^:]", settb->tb_expr);
65 
66  return 0;
67 }
68 
69 static int config_output_props(AVFilterLink *outlink)
70 {
71  AVFilterContext *ctx = outlink->src;
72  SetTBContext *settb = ctx->priv;
73  AVFilterLink *inlink = ctx->inputs[0];
74  AVRational time_base;
75  int ret;
76  double res;
77 
79  settb->var_values[VAR_INTB] = av_q2d(inlink->time_base);
80  settb->var_values[VAR_SR] = inlink->sample_rate;
81 
82  outlink->w = inlink->w;
83  outlink->h = inlink->h;
84 
85  if ((ret = av_expr_parse_and_eval(&res, settb->tb_expr, var_names, settb->var_values,
86  NULL, NULL, NULL, NULL, NULL, 0, NULL)) < 0) {
87  av_log(ctx, AV_LOG_ERROR, "Invalid expression '%s' for timebase.\n", settb->tb_expr);
88  return ret;
89  }
90  time_base = av_d2q(res, INT_MAX);
91  if (time_base.num <= 0 || time_base.den <= 0) {
92  av_log(ctx, AV_LOG_ERROR,
93  "Invalid non-positive values for the timebase num:%d or den:%d.\n",
94  time_base.num, time_base.den);
95  return AVERROR(EINVAL);
96  }
97 
98  outlink->time_base = time_base;
99  av_log(outlink->src, AV_LOG_VERBOSE, "tb:%d/%d -> tb:%d/%d\n",
100  inlink ->time_base.num, inlink ->time_base.den,
101  outlink->time_base.num, outlink->time_base.den);
102 
103  return 0;
104 }
105 
107 {
108  AVFilterContext *ctx = inlink->dst;
109  AVFilterLink *outlink = ctx->outputs[0];
110 
111  if (av_cmp_q(inlink->time_base, outlink->time_base)) {
112  int64_t orig_pts = frame->pts;
113  frame->pts = av_rescale_q(frame->pts, inlink->time_base, outlink->time_base);
114  av_log(ctx, AV_LOG_DEBUG, "tb:%d/%d pts:%"PRId64" -> tb:%d/%d pts:%"PRId64"\n",
115  inlink ->time_base.num, inlink ->time_base.den, orig_pts,
116  outlink->time_base.num, outlink->time_base.den, frame->pts);
117  }
118 
119  return ff_filter_frame(outlink, frame);
120 }
121 
122 #if CONFIG_SETTB_FILTER
123 static const AVFilterPad avfilter_vf_settb_inputs[] = {
124  {
125  .name = "default",
126  .type = AVMEDIA_TYPE_VIDEO,
127  .get_video_buffer = ff_null_get_video_buffer,
128  .filter_frame = filter_frame,
129  },
130  { NULL }
131 };
132 
133 static const AVFilterPad avfilter_vf_settb_outputs[] = {
134  {
135  .name = "default",
136  .type = AVMEDIA_TYPE_VIDEO,
137  .config_props = config_output_props,
138  },
139  { NULL }
140 };
141 
142 AVFilter avfilter_vf_settb = {
143  .name = "settb",
144  .description = NULL_IF_CONFIG_SMALL("Set timebase for the video output link."),
145  .init = init,
146 
147  .priv_size = sizeof(SetTBContext),
148 
149  .inputs = avfilter_vf_settb_inputs,
150  .outputs = avfilter_vf_settb_outputs,
151 };
152 #endif
153 
154 #if CONFIG_ASETTB_FILTER
155 static const AVFilterPad avfilter_af_asettb_inputs[] = {
156  {
157  .name = "default",
158  .type = AVMEDIA_TYPE_AUDIO,
159  .get_audio_buffer = ff_null_get_audio_buffer,
160  .filter_frame = filter_frame,
161  },
162  { NULL }
163 };
164 
165 static const AVFilterPad avfilter_af_asettb_outputs[] = {
166  {
167  .name = "default",
168  .type = AVMEDIA_TYPE_AUDIO,
169  .config_props = config_output_props,
170  },
171  { NULL }
172 };
173 
174 AVFilter avfilter_af_asettb = {
175  .name = "asettb",
176  .description = NULL_IF_CONFIG_SMALL("Set timebase for the audio output link."),
177  .init = init,
178 
179  .priv_size = sizeof(SetTBContext),
180  .inputs = avfilter_af_asettb_inputs,
181  .outputs = avfilter_af_asettb_outputs,
182 };
183 #endif