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 libavfilter/vf_vflip.c
  23  * video vertical flip filter
  24  */
  25
  26 #include "avfilter.h"
  27
  28 typedef struct {
  29     int vsub;   ///< vertical chroma subsampling
  30 } FlipContext;
  31
  32 static int config_input(AVFilterLink *link)
  33 {
  34     FlipContext *flip = link->dst->priv;
  35     int tmp;
  36
  37     avcodec_get_chroma_sub_sample(link->format, &tmp, &flip->vsub);
  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     picref->data[0] += (h-1) * picref->linesize[0];
  52     picref->linesize[0] = -picref->linesize[0];
  53     for (i = 1; i < 4; i ++) {
  54         if (picref->data[i]) {
  55             picref->data[i] += ((h >> flip->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     AVFilterPicRef *ref2 = avfilter_ref_pic(picref, ~0);
  67     int i;
  68
  69     ref2->data[0] += (link->h-1) * ref2->linesize[0];
  70     ref2->linesize[0] = -ref2->linesize[0];
  71     for (i = 1; i < 4; i ++) {
  72         if (ref2->data[i]) {
  73             ref2->data[i] += ((link->h >> flip->vsub)-1) * ref2->linesize[i];
  74             ref2->linesize[i] = -ref2->linesize[i];
  75         }
  76     }
  77
  78     avfilter_start_frame(link->dst->outputs[0], ref2);
  79 }
  80
  81 static void draw_slice(AVFilterLink *link, int y, int h)
  82 {
  83     AVFilterContext *ctx = link->dst;
  84
  85     avfilter_draw_slice(ctx->outputs[0], link->h - (y+h), h);
  86 }
  87
  88 AVFilter avfilter_vf_vflip = {
  89     .name      = "vflip",
  90     .priv_size = sizeof(FlipContext),
  91
  92     .inputs    = (AVFilterPad[]) {{ .name             = "default",
  93                                     .type             = CODEC_TYPE_VIDEO,
  94                                     .get_video_buffer = get_video_buffer,
  95                                     .start_frame      = start_frame,
  96                                     .draw_slice       = draw_slice,
  97                                     .config_props     = config_input, },
  98                                   { .name = NULL}},
  99     .outputs   = (AVFilterPad[]) {{ .name             = "default",
 100                                     .type             = CODEC_TYPE_VIDEO, },
 101                                   { .name = NULL}},
 102 };