libavfilter/vf_crop.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 crop filter
  24  */
  25
  26 #include "avfilter.h"
  27 #include "libavutil/pixdesc.h"
  28
  29 typedef struct {
  30     int  x;             ///< x offset of the non-cropped area with respect to the input area
  31     int  y;             ///< y offset of the non-cropped area with respect to the input area
  32     int  w;             ///< width of the cropped area
  33     int  h;             ///< height of the cropped area
  34
  35     int bpp;            ///< bits per pixel
  36     int hsub, vsub;     ///< chroma subsampling
  37 } CropContext;
  38
  39 static int query_formats(AVFilterContext *ctx)
  40 {
  41     static const enum PixelFormat pix_fmts[] = {
  42         PIX_FMT_RGB48BE,      PIX_FMT_RGB48LE,
  43         PIX_FMT_ARGB,         PIX_FMT_RGBA,
  44         PIX_FMT_ABGR,         PIX_FMT_BGRA,
  45         PIX_FMT_RGB24,        PIX_FMT_BGR24,
  46         PIX_FMT_RGB565BE,     PIX_FMT_RGB565LE,
  47         PIX_FMT_RGB555BE,     PIX_FMT_RGB555LE,
  48         PIX_FMT_BGR565BE,     PIX_FMT_BGR565LE,
  49         PIX_FMT_BGR555BE,     PIX_FMT_BGR555LE,
  50         PIX_FMT_GRAY16BE,     PIX_FMT_GRAY16LE,
  51         PIX_FMT_YUV420P16LE,  PIX_FMT_YUV420P16BE,
  52         PIX_FMT_YUV422P16LE,  PIX_FMT_YUV422P16BE,
  53         PIX_FMT_YUV444P16LE,  PIX_FMT_YUV444P16BE,
  54         PIX_FMT_YUV444P,      PIX_FMT_YUV422P,
  55         PIX_FMT_YUV420P,      PIX_FMT_YUV411P,
  56         PIX_FMT_YUV410P,      PIX_FMT_YUV440P,
  57         PIX_FMT_YUVJ444P,     PIX_FMT_YUVJ422P,
  58         PIX_FMT_YUVJ420P,     PIX_FMT_YUVJ440P,
  59         PIX_FMT_YUVA420P,
  60         PIX_FMT_RGB8,         PIX_FMT_BGR8,
  61         PIX_FMT_RGB4_BYTE,    PIX_FMT_BGR4_BYTE,
  62         PIX_FMT_PAL8,         PIX_FMT_GRAY8,
  63         PIX_FMT_NONE
  64     };
  65
  66     avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
  67
  68     return 0;
  69 }
  70
  71 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
  72 {
  73     CropContext *crop = ctx->priv;
  74
  75     if (args)
  76         sscanf(args, "%d:%d:%d:%d", &crop->x, &crop->y, &crop->w, &crop->h);
  77
  78     return 0;
  79 }
  80
  81 static int config_input(AVFilterLink *link)
  82 {
  83     AVFilterContext *ctx = link->dst;
  84     CropContext *crop = ctx->priv;
  85
  86     switch (link->format) {
  87     case PIX_FMT_RGB48BE:
  88     case PIX_FMT_RGB48LE:
  89         crop->bpp = 48;
  90         break;
  91     case PIX_FMT_ARGB:
  92     case PIX_FMT_RGBA:
  93     case PIX_FMT_ABGR:
  94     case PIX_FMT_BGRA:
  95         crop->bpp = 32;
  96         break;
  97     case PIX_FMT_RGB24:
  98     case PIX_FMT_BGR24:
  99         crop->bpp = 24;
 100         break;
 101     case PIX_FMT_RGB565BE:
 102     case PIX_FMT_RGB565LE:
 103     case PIX_FMT_RGB555BE:
 104     case PIX_FMT_RGB555LE:
 105     case PIX_FMT_BGR565BE:
 106     case PIX_FMT_BGR565LE:
 107     case PIX_FMT_BGR555BE:
 108     case PIX_FMT_BGR555LE:
 109     case PIX_FMT_GRAY16BE:
 110     case PIX_FMT_GRAY16LE:
 111     case PIX_FMT_YUV420P16LE:
 112     case PIX_FMT_YUV420P16BE:
 113     case PIX_FMT_YUV422P16LE:
 114     case PIX_FMT_YUV422P16BE:
 115     case PIX_FMT_YUV444P16LE:
 116     case PIX_FMT_YUV444P16BE:
 117         crop->bpp = 16;
 118         break;
 119     default:
 120         crop->bpp = 8;
 121     }
 122
 123     avcodec_get_chroma_sub_sample(link->format, &crop->hsub, &crop->vsub);
 124
 125     if (crop->w == 0)
 126         crop->w = link->w - crop->x;
 127     if (crop->h == 0)
 128         crop->h = link->h - crop->y;
 129
 130     crop->x &= ~((1 << crop->hsub) - 1);
 131     crop->y &= ~((1 << crop->vsub) - 1);
 132
 133     av_log(link->dst, AV_LOG_INFO, "x:%d y:%d w:%d h:%d\n",
 134            crop->x, crop->y, crop->w, crop->h);
 135
 136     if (crop->x <  0 || crop->y <  0                    ||
 137         crop->w <= 0 || crop->h <= 0                    ||
 138         (unsigned)crop->x + (unsigned)crop->w > link->w ||
 139         (unsigned)crop->y + (unsigned)crop->h > link->h) {
 140         av_log(ctx, AV_LOG_ERROR,
 141                "Output area %d:%d:%d:%d not within the input area 0:0:%d:%d or zero-sized\n",
 142                crop->x, crop->y, crop->w, crop->h, link->w, link->h);
 143         return -1;
 144     }
 145
 146     return 0;
 147 }
 148
 149 static int config_output(AVFilterLink *link)
 150 {
 151     CropContext *crop = link->src->priv;
 152
 153     link->w = crop->w;
 154     link->h = crop->h;
 155
 156     return 0;
 157 }
 158
 159 static void start_frame(AVFilterLink *link, AVFilterPicRef *picref)
 160 {
 161     CropContext *crop = link->dst->priv;
 162     AVFilterPicRef *ref2 = avfilter_ref_pic(picref, ~0);
 163     int i;
 164
 165     ref2->w        = crop->w;
 166     ref2->h        = crop->h;
 167
 168     ref2->data[0] += crop->y * ref2->linesize[0];
 169     ref2->data[0] += (crop->x * crop->bpp) >> 3;
 170
 171     if (!(av_pix_fmt_descriptors[link->format].flags & PIX_FMT_PAL)) {
 172         for (i = 1; i < 3; i ++) {
 173             if (ref2->data[i]) {
 174                 ref2->data[i] += (crop->y >> crop->vsub) * ref2->linesize[i];
 175                 ref2->data[i] += ((crop->x * crop->bpp) >> 3) >> crop->hsub;
 176             }
 177         }
 178     }
 179
 180     /* alpha plane */
 181     if (ref2->data[3]) {
 182         ref2->data[3] += crop->y * ref2->linesize[3];
 183         ref2->data[3] += (crop->x * crop->bpp) >> 3;
 184     }
 185
 186     avfilter_start_frame(link->dst->outputs[0], ref2);
 187 }
 188
 189 static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
 190 {
 191     AVFilterContext *ctx = link->dst;
 192     CropContext *crop = ctx->priv;
 193
 194     if (y >= crop->y + crop->h || y + h <= crop->y)
 195         return;
 196
 197     if (y < crop->y) {
 198         h -= crop->y - y;
 199         y  = crop->y;
 200     }
 201     if (y + h > crop->y + crop->h)
 202         h = crop->y + crop->h - y;
 203
 204     avfilter_draw_slice(ctx->outputs[0], y - crop->y, h, slice_dir);
 205 }
 206
 207 AVFilter avfilter_vf_crop = {
 208     .name      = "crop",
 209     .description = NULL_IF_CONFIG_SMALL("Crop the input video to x:y:width:height."),
 210
 211     .priv_size = sizeof(CropContext),
 212
 213     .query_formats = query_formats,
 214     .init          = init,
 215
 216     .inputs    = (AVFilterPad[]) {{ .name             = "default",
 217                                     .type             = AVMEDIA_TYPE_VIDEO,
 218                                     .start_frame      = start_frame,
 219                                     .draw_slice       = draw_slice,
 220                                     .get_video_buffer = avfilter_null_get_video_buffer,
 221                                     .config_props     = config_input, },
 222                                   { .name = NULL}},
 223     .outputs   = (AVFilterPad[]) {{ .name             = "default",
 224                                     .type             = AVMEDIA_TYPE_VIDEO,
 225                                     .config_props     = config_output, },
 226                                   { .name = NULL}},
 227 };