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 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
  59         if (frame->data[i]) {
  60             frame->data[i] += ((h >> vsub) - 1) * frame->linesize[i];
  61             frame->linesize[i] = -frame->linesize[i];
  62         }
  63     }
  64
  65     return frame;
  66 }
  67
  68 static int filter_frame(AVFilterLink *link, AVFrame *frame)
  69 {
  70     FlipContext *flip = link->dst->priv;
  71     int i;
  72
  73     for (i = 0; i < 4; i ++) {
  74         int vsub = i == 1 || i == 2 ? flip->vsub : 0;
  75
  76         if (frame->data[i]) {
  77             frame->data[i] += ((link->h >> vsub)-1) * frame->linesize[i];
  78             frame->linesize[i] = -frame->linesize[i];
  79         }
  80     }
  81
  82     return ff_filter_frame(link->dst->outputs[0], frame);
  83 }
  84 static const AVFilterPad avfilter_vf_vflip_inputs[] = {
  85     {
  86         .name             = "default",
  87         .type             = AVMEDIA_TYPE_VIDEO,
  88         .get_video_buffer = get_video_buffer,
  89         .filter_frame     = filter_frame,
  90         .config_props     = config_input,
  91     },
  92     { NULL }
  93 };
  94
  95 static const AVFilterPad avfilter_vf_vflip_outputs[] = {
  96     {
  97         .name = "default",
  98         .type = AVMEDIA_TYPE_VIDEO,
  99     },
 100     { NULL }
 101 };
 102
 103 AVFilter avfilter_vf_vflip = {
 104     .name      = "vflip",
 105     .description = NULL_IF_CONFIG_SMALL("Flip the input video vertically."),
 106
 107     .priv_size = sizeof(FlipContext),
 108
 109     .inputs    = avfilter_vf_vflip_inputs,
 110     .outputs   = avfilter_vf_vflip_outputs,
 111 };