libavfilter/vf_vflip.c

   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/pixdesc.h"
  27 #include "avfilter.h"
  28
  29 typedef struct {
  30     int vsub;   ///< vertical chroma subsampling
  31 } FlipContext;
  32
  33 static int config_input(AVFilterLink *link)
  34 {
  35     FlipContext *flip = link->dst->priv;
  36
  37     flip->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h;
  38
  39     return 0;
  40 }
  41
  42 static AVFilterPicRef *get_video_buffer(AVFilterLink *link, int perms,
  43                                         int w, int h)
  44 {
  45     FlipContext *flip = link->dst->priv;
  46     int i;
  47
  48     AVFilterPicRef *picref = avfilter_get_video_buffer(link->dst->outputs[0],
  49                                                        perms, w, h);
  50
  51     for (i = 0; i < 4; i ++) {
  52         int vsub = i == 1 || i == 2 ? flip->vsub : 0;
  53
  54         if (picref->data[i]) {
  55             picref->data[i] += ((h >> vsub)-1) * picref->linesize[i];
  56             picref->linesize[i] = -picref->linesize[i];
  57         }
  58     }
  59
  60     return picref;
  61 }
  62
  63 static void start_frame(AVFilterLink *link, AVFilterPicRef *picref)
  64 {
  65     FlipContext *flip = link->dst->priv;
  66     int i;
  67
  68     for (i = 0; i < 4; i ++) {
  69         int vsub = i == 1 || i == 2 ? flip->vsub : 0;
  70
  71         if (picref->data[i]) {
  72             picref->data[i] += ((link->h >> vsub)-1) * picref->linesize[i];
  73             picref->linesize[i] = -picref->linesize[i];
  74         }
  75     }
  76
  77     avfilter_start_frame(link->dst->outputs[0], picref);
  78 }
  79
  80 static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
  81 {
  82     AVFilterContext *ctx = link->dst;
  83
  84     avfilter_draw_slice(ctx->outputs[0], link->h - (y+h), h, -1 * slice_dir);
  85 }
  86
  87 AVFilter avfilter_vf_vflip = {
  88     .name      = "vflip",
  89     .description = NULL_IF_CONFIG_SMALL("Flip the input video vertically."),
  90
  91     .priv_size = sizeof(FlipContext),
  92
  93     .inputs    = (AVFilterPad[]) {{ .name             = "default",
  94                                     .type             = AVMEDIA_TYPE_VIDEO,
  95                                     .get_video_buffer = get_video_buffer,
  96                                     .start_frame      = start_frame,
  97                                     .draw_slice       = draw_slice,
  98                                     .end_frame        = avfilter_null_end_frame,
  99                                     .config_props     = config_input, },
 100                                   { .name = NULL}},
 101     .outputs   = (AVFilterPad[]) {{ .name             = "default",
 102                                     .type             = AVMEDIA_TYPE_VIDEO, },
 103                                   { .name = NULL}},
 104 };