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vf_separatefields.c
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1 /*
2  * Copyright (c) 2013 Paul B Mahol
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 #include "libavutil/pixdesc.h"
22 #include "avfilter.h"
23 #include "internal.h"
24 
25 typedef struct {
26  int nb_planes;
29 
30 static int config_props_output(AVFilterLink *outlink)
31 {
32  AVFilterContext *ctx = outlink->src;
33  SeparateFieldsContext *sf = ctx->priv;
34  AVFilterLink *inlink = ctx->inputs[0];
35 
37 
38  if (inlink->h & 1) {
39  av_log(ctx, AV_LOG_ERROR, "height must be even\n");
40  return AVERROR_INVALIDDATA;
41  }
42 
43  outlink->time_base.num = inlink->time_base.num;
44  outlink->time_base.den = inlink->time_base.den * 2;
45  outlink->frame_rate.num = inlink->frame_rate.num * 2;
46  outlink->frame_rate.den = inlink->frame_rate.den;
47  outlink->w = inlink->w;
48  outlink->h = inlink->h / 2;
49 
50  return 0;
51 }
52 
53 static void extract_field(AVFrame *frame, int nb_planes, int type)
54 {
55  int i;
56 
57  for (i = 0; i < nb_planes; i++) {
58  if (type)
59  frame->data[i] = frame->data[i] + frame->linesize[i];
60  frame->linesize[i] *= 2;
61  }
62 }
63 
64 static int filter_frame(AVFilterLink *inlink, AVFrame *inpicref)
65 {
66  AVFilterContext *ctx = inlink->dst;
67  SeparateFieldsContext *sf = ctx->priv;
68  AVFilterLink *outlink = ctx->outputs[0];
69  int ret;
70 
71  inpicref->height = outlink->h;
72  inpicref->interlaced_frame = 0;
73 
74  if (!sf->second) {
75  goto clone;
76  } else {
77  AVFrame *second = sf->second;
78 
79  extract_field(second, sf->nb_planes, second->top_field_first);
80 
81  if (second->pts != AV_NOPTS_VALUE &&
82  inpicref->pts != AV_NOPTS_VALUE)
83  second->pts += inpicref->pts;
84  else
85  second->pts = AV_NOPTS_VALUE;
86 
87  ret = ff_filter_frame(outlink, second);
88  if (ret < 0)
89  return ret;
90 clone:
91  sf->second = av_frame_clone(inpicref);
92  if (!sf->second)
93  return AVERROR(ENOMEM);
94  }
95 
96  extract_field(inpicref, sf->nb_planes, !inpicref->top_field_first);
97 
98  if (inpicref->pts != AV_NOPTS_VALUE)
99  inpicref->pts *= 2;
100 
101  return ff_filter_frame(outlink, inpicref);
102 }
103 
104 static int request_frame(AVFilterLink *outlink)
105 {
106  AVFilterContext *ctx = outlink->src;
107  SeparateFieldsContext *sf = ctx->priv;
108  int ret;
109 
110  ret = ff_request_frame(ctx->inputs[0]);
111  if (ret == AVERROR_EOF && sf->second) {
112  sf->second->pts *= 2;
114  ret = ff_filter_frame(outlink, sf->second);
115  sf->second = 0;
116  }
117 
118  return ret;
119 }
120 
122  {
123  .name = "default",
124  .type = AVMEDIA_TYPE_VIDEO,
125  .filter_frame = filter_frame,
126  },
127  { NULL }
128 };
129 
131  {
132  .name = "default",
133  .type = AVMEDIA_TYPE_VIDEO,
134  .config_props = config_props_output,
135  .request_frame = request_frame,
136  },
137  { NULL }
138 };
139 
141  .name = "separatefields",
142  .description = NULL_IF_CONFIG_SMALL("Split input video frames into fields."),
143  .priv_size = sizeof(SeparateFieldsContext),
144  .inputs = separatefields_inputs,
145  .outputs = separatefields_outputs,
146 };