libavfilter/vf_vflip.c

   1 /*
   2  * Copyright (c) 2007 Bobby Bingham
   3  *
   4  * This file is part of Libav.
   5  *
   6  * Libav 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  * Libav 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 Libav; 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 AVFilterBufferRef *get_video_buffer(AVFilterLink *link, int perms,
  47                                         int w, int h)
  48 {
  49     FlipContext *flip = link->dst->priv;
  50     AVFilterBufferRef *picref;
  51     int i;
  52
  53     if (!(perms & AV_PERM_NEG_LINESIZES))
  54         return ff_default_get_video_buffer(link, perms, w, h);
  55
  56     picref = ff_get_video_buffer(link->dst->outputs[0], perms, w, h);
  57     if (!picref)
  58         return NULL;
  59
  60     for (i = 0; i < 4; i ++) {
  61         int vsub = i == 1 || i == 2 ? flip->vsub : 0;
  62
  63         if (picref->data[i]) {
  64             picref->data[i] += ((h >> vsub)-1) * picref->linesize[i];
  65             picref->linesize[i] = -picref->linesize[i];
  66         }
  67     }
  68
  69     return picref;
  70 }
  71
  72 static int filter_frame(AVFilterLink *link, AVFilterBufferRef *frame)
  73 {
  74     FlipContext *flip = link->dst->priv;
  75     int i;
  76
  77     for (i = 0; i < 4; i ++) {
  78         int vsub = i == 1 || i == 2 ? flip->vsub : 0;
  79
  80         if (frame->data[i]) {
  81             frame->data[i] += ((link->h >> vsub)-1) * frame->linesize[i];
  82             frame->linesize[i] = -frame->linesize[i];
  83         }
  84     }
  85
  86     return ff_filter_frame(link->dst->outputs[0], frame);
  87 }
  88 static const AVFilterPad avfilter_vf_vflip_inputs[] = {
  89     {
  90         .name             = "default",
  91         .type             = AVMEDIA_TYPE_VIDEO,
  92         .get_video_buffer = get_video_buffer,
  93         .filter_frame     = filter_frame,
  94         .config_props     = config_input,
  95     },
  96     { NULL }
  97 };
  98
  99 static const AVFilterPad avfilter_vf_vflip_outputs[] = {
 100     {
 101         .name = "default",
 102         .type = AVMEDIA_TYPE_VIDEO,
 103     },
 104     { NULL }
 105 };
 106
 107 AVFilter avfilter_vf_vflip = {
 108     .name      = "vflip",
 109     .description = NULL_IF_CONFIG_SMALL("Flip the input video vertically."),
 110
 111     .priv_size = sizeof(FlipContext),
 112
 113     .inputs    = avfilter_vf_vflip_inputs,
 114     .outputs   = avfilter_vf_vflip_outputs,
 115 };