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vf_vflip.c
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1 /*
2  * Copyright (c) 2007 Bobby Bingham
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  * video vertical flip filter
24  */
25 
26 #include "libavutil/internal.h"
27 #include "libavutil/pixdesc.h"
28 #include "avfilter.h"
29 #include "internal.h"
30 #include "video.h"
31 
32 typedef struct {
33  int vsub; ///< vertical chroma subsampling
34 } FlipContext;
35 
36 static int config_input(AVFilterLink *link)
37 {
38  FlipContext *flip = link->dst->priv;
39  const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
40 
41  flip->vsub = desc->log2_chroma_h;
42 
43  return 0;
44 }
45 
46 static AVFrame *get_video_buffer(AVFilterLink *link, int w, int h)
47 {
48  FlipContext *flip = link->dst->priv;
49  AVFrame *frame;
50  int i;
51 
52  frame = ff_get_video_buffer(link->dst->outputs[0], w, h);
53  if (!frame)
54  return NULL;
55 
56  for (i = 0; i < 4; i ++) {
57  int vsub = i == 1 || i == 2 ? flip->vsub : 0;
58  int height = FF_CEIL_RSHIFT(h, vsub);
59 
60  if (frame->data[i]) {
61  frame->data[i] += (height - 1) * frame->linesize[i];
62  frame->linesize[i] = -frame->linesize[i];
63  }
64  }
65 
66  return frame;
67 }
68 
70 {
71  FlipContext *flip = link->dst->priv;
72  int i;
73 
74  for (i = 0; i < 4; i ++) {
75  int vsub = i == 1 || i == 2 ? flip->vsub : 0;
76  int height = FF_CEIL_RSHIFT(link->h, vsub);
77 
78  if (frame->data[i]) {
79  frame->data[i] += (height - 1) * frame->linesize[i];
80  frame->linesize[i] = -frame->linesize[i];
81  }
82  }
83 
84  return ff_filter_frame(link->dst->outputs[0], frame);
85 }
87  {
88  .name = "default",
89  .type = AVMEDIA_TYPE_VIDEO,
90  .get_video_buffer = get_video_buffer,
91  .filter_frame = filter_frame,
92  .config_props = config_input,
93  },
94  { NULL }
95 };
96 
98  {
99  .name = "default",
100  .type = AVMEDIA_TYPE_VIDEO,
101  },
102  { NULL }
103 };
104 
106  .name = "vflip",
107  .description = NULL_IF_CONFIG_SMALL("Flip the input video vertically."),
108  .priv_size = sizeof(FlipContext),
109  .inputs = avfilter_vf_vflip_inputs,
110  .outputs = avfilter_vf_vflip_outputs,
111 };