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 max_step[4];    ///< max pixel step for each plane, expressed as a number of bytes
  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     const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[link->format];
  86     int i;
  87
  88     memset(crop->max_step, 0, sizeof(crop->max_step));
  89     for (i = 0; i < 4; i++) {
  90         const AVComponentDescriptor *comp = &(pix_desc->comp[i]);
  91         if ((comp->step_minus1+1) > crop->max_step[comp->plane])
  92             crop->max_step[comp->plane] = comp->step_minus1+1;
  93     }
  94
  95     crop->hsub = av_pix_fmt_descriptors[link->format].log2_chroma_w;
  96     crop->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h;
  97
  98     if (crop->w == 0)
  99         crop->w = link->w - crop->x;
 100     if (crop->h == 0)
 101         crop->h = link->h - crop->y;
 102
 103     crop->x &= ~((1 << crop->hsub) - 1);
 104     crop->y &= ~((1 << crop->vsub) - 1);
 105
 106     av_log(link->dst, AV_LOG_INFO, "x:%d y:%d w:%d h:%d\n",
 107            crop->x, crop->y, crop->w, crop->h);
 108
 109     if (crop->x <  0 || crop->y <  0                    ||
 110         crop->w <= 0 || crop->h <= 0                    ||
 111         (unsigned)crop->x + (unsigned)crop->w > link->w ||
 112         (unsigned)crop->y + (unsigned)crop->h > link->h) {
 113         av_log(ctx, AV_LOG_ERROR,
 114                "Output area %d:%d:%d:%d not within the input area 0:0:%d:%d or zero-sized\n",
 115                crop->x, crop->y, crop->w, crop->h, link->w, link->h);
 116         return -1;
 117     }
 118
 119     return 0;
 120 }
 121
 122 static int config_output(AVFilterLink *link)
 123 {
 124     CropContext *crop = link->src->priv;
 125
 126     link->w = crop->w;
 127     link->h = crop->h;
 128
 129     return 0;
 130 }
 131
 132 static void start_frame(AVFilterLink *link, AVFilterPicRef *picref)
 133 {
 134     CropContext *crop = link->dst->priv;
 135     AVFilterPicRef *ref2 = avfilter_ref_pic(picref, ~0);
 136     int i;
 137
 138     ref2->w        = crop->w;
 139     ref2->h        = crop->h;
 140
 141     ref2->data[0] += crop->y * ref2->linesize[0];
 142     ref2->data[0] += (crop->x * crop->max_step[0]);
 143
 144     if (!(av_pix_fmt_descriptors[link->format].flags & PIX_FMT_PAL)) {
 145         for (i = 1; i < 3; i ++) {
 146             if (ref2->data[i]) {
 147                 ref2->data[i] += (crop->y >> crop->vsub) * ref2->linesize[i];
 148                 ref2->data[i] += (crop->x * crop->max_step[i]) >> crop->hsub;
 149             }
 150         }
 151     }
 152
 153     /* alpha plane */
 154     if (ref2->data[3]) {
 155         ref2->data[3] += crop->y * ref2->linesize[3];
 156         ref2->data[3] += (crop->x * crop->max_step[3]);
 157     }
 158
 159     avfilter_start_frame(link->dst->outputs[0], ref2);
 160 }
 161
 162 static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
 163 {
 164     AVFilterContext *ctx = link->dst;
 165     CropContext *crop = ctx->priv;
 166
 167     if (y >= crop->y + crop->h || y + h <= crop->y)
 168         return;
 169
 170     if (y < crop->y) {
 171         h -= crop->y - y;
 172         y  = crop->y;
 173     }
 174     if (y + h > crop->y + crop->h)
 175         h = crop->y + crop->h - y;
 176
 177     avfilter_draw_slice(ctx->outputs[0], y - crop->y, h, slice_dir);
 178 }
 179
 180 AVFilter avfilter_vf_crop = {
 181     .name      = "crop",
 182     .description = NULL_IF_CONFIG_SMALL("Crop the input video to x:y:width:height."),
 183
 184     .priv_size = sizeof(CropContext),
 185
 186     .query_formats = query_formats,
 187     .init          = init,
 188
 189     .inputs    = (AVFilterPad[]) {{ .name             = "default",
 190                                     .type             = AVMEDIA_TYPE_VIDEO,
 191                                     .start_frame      = start_frame,
 192                                     .draw_slice       = draw_slice,
 193                                     .get_video_buffer = avfilter_null_get_video_buffer,
 194                                     .config_props     = config_input, },
 195                                   { .name = NULL}},
 196     .outputs   = (AVFilterPad[]) {{ .name             = "default",
 197                                     .type             = AVMEDIA_TYPE_VIDEO,
 198                                     .config_props     = config_output, },
 199                                   { .name = NULL}},
 200 };