libavfilter/vf_cropdetect.c

   1 /*
   2  * Copyright (c) 2002 A'rpi
   3  * This file is part of Libav.
   4  *
   5  * Libav is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * Libav is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with Libav; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 /**
  21  * @file
  22  * border detection filter
  23  * Ported from MPlayer libmpcodecs/vf_cropdetect.c.
  24  */
  25
  26 #include <stdio.h>
  27
  28 #include "libavutil/imgutils.h"
  29 #include "libavutil/internal.h"
  30 #include "avfilter.h"
  31 #include "formats.h"
  32 #include "internal.h"
  33 #include "video.h"
  34
  35 typedef struct {
  36     int x1, y1, x2, y2;
  37     int limit;
  38     int round;
  39     int reset_count;
  40     int frame_nb;
  41     int max_pixsteps[4];
  42 } CropDetectContext;
  43
  44 static int query_formats(AVFilterContext *ctx)
  45 {
  46     static const enum AVPixelFormat pix_fmts[] = {
  47         AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUVJ420P,
  48         AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUVJ422P,
  49         AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUVJ444P,
  50         AV_PIX_FMT_YUV411P, AV_PIX_FMT_GRAY8,
  51         AV_PIX_FMT_NV12,    AV_PIX_FMT_NV21,
  52         AV_PIX_FMT_NONE
  53     };
  54
  55     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
  56     return 0;
  57 }
  58
  59 static int checkline(void *ctx, const unsigned char *src, int stride, int len, int bpp)
  60 {
  61     int total = 0;
  62     int div = len;
  63
  64     switch (bpp) {
  65     case 1:
  66         while (--len >= 0) {
  67             total += src[0];
  68             src += stride;
  69         }
  70         break;
  71     case 3:
  72     case 4:
  73         while (--len >= 0) {
  74             total += src[0] + src[1] + src[2];
  75             src += stride;
  76         }
  77         div *= 3;
  78         break;
  79     }
  80     total /= div;
  81
  82     av_log(ctx, AV_LOG_DEBUG, "total:%d\n", total);
  83     return total;
  84 }
  85
  86 static av_cold int init(AVFilterContext *ctx, const char *args)
  87 {
  88     CropDetectContext *cd = ctx->priv;
  89
  90     cd->limit = 24;
  91     cd->round = 0;
  92     cd->reset_count = 0;
  93     cd->frame_nb = -2;
  94
  95     if (args)
  96         sscanf(args, "%d:%d:%d", &cd->limit, &cd->round, &cd->reset_count);
  97
  98     av_log(ctx, AV_LOG_VERBOSE, "limit:%d round:%d reset_count:%d\n",
  99            cd->limit, cd->round, cd->reset_count);
 100
 101     return 0;
 102 }
 103
 104 static int config_input(AVFilterLink *inlink)
 105 {
 106     AVFilterContext *ctx = inlink->dst;
 107     CropDetectContext *cd = ctx->priv;
 108
 109     av_image_fill_max_pixsteps(cd->max_pixsteps, NULL,
 110                                av_pix_fmt_desc_get(inlink->format));
 111
 112     cd->x1 = inlink->w - 1;
 113     cd->y1 = inlink->h - 1;
 114     cd->x2 = 0;
 115     cd->y2 = 0;
 116
 117     return 0;
 118 }
 119
 120 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *frame)
 121 {
 122     AVFilterContext *ctx = inlink->dst;
 123     CropDetectContext *cd = ctx->priv;
 124     int bpp = cd->max_pixsteps[0];
 125     int w, h, x, y, shrink_by;
 126
 127     // ignore first 2 frames - they may be empty
 128     if (++cd->frame_nb > 0) {
 129         // Reset the crop area every reset_count frames, if reset_count is > 0
 130         if (cd->reset_count > 0 && cd->frame_nb > cd->reset_count) {
 131             cd->x1 = frame->video->w-1;
 132             cd->y1 = frame->video->h-1;
 133             cd->x2 = 0;
 134             cd->y2 = 0;
 135             cd->frame_nb = 1;
 136         }
 137
 138         for (y = 0; y < cd->y1; y++) {
 139             if (checkline(ctx, frame->data[0] + frame->linesize[0] * y, bpp, frame->video->w, bpp) > cd->limit) {
 140                 cd->y1 = y;
 141                 break;
 142             }
 143         }
 144
 145         for (y = frame->video->h-1; y > cd->y2; y--) {
 146             if (checkline(ctx, frame->data[0] + frame->linesize[0] * y, bpp, frame->video->w, bpp) > cd->limit) {
 147                 cd->y2 = y;
 148                 break;
 149             }
 150         }
 151
 152         for (y = 0; y < cd->x1; y++) {
 153             if (checkline(ctx, frame->data[0] + bpp*y, frame->linesize[0], frame->video->h, bpp) > cd->limit) {
 154                 cd->x1 = y;
 155                 break;
 156             }
 157         }
 158
 159         for (y = frame->video->w-1; y > cd->x2; y--) {
 160             if (checkline(ctx, frame->data[0] + bpp*y, frame->linesize[0], frame->video->h, bpp) > cd->limit) {
 161                 cd->x2 = y;
 162                 break;
 163             }
 164         }
 165
 166         // round x and y (up), important for yuv colorspaces
 167         // make sure they stay rounded!
 168         x = (cd->x1+1) & ~1;
 169         y = (cd->y1+1) & ~1;
 170
 171         w = cd->x2 - x + 1;
 172         h = cd->y2 - y + 1;
 173
 174         // w and h must be divisible by 2 as well because of yuv
 175         // colorspace problems.
 176         if (cd->round <= 1)
 177             cd->round = 16;
 178         if (cd->round % 2)
 179             cd->round *= 2;
 180
 181         shrink_by = w % cd->round;
 182         w -= shrink_by;
 183         x += (shrink_by/2 + 1) & ~1;
 184
 185         shrink_by = h % cd->round;
 186         h -= shrink_by;
 187         y += (shrink_by/2 + 1) & ~1;
 188
 189         av_log(ctx, AV_LOG_INFO,
 190                "x1:%d x2:%d y1:%d y2:%d w:%d h:%d x:%d y:%d pos:%"PRId64" pts:%"PRId64" t:%f crop=%d:%d:%d:%d\n",
 191                cd->x1, cd->x2, cd->y1, cd->y2, w, h, x, y, frame->pos, frame->pts,
 192                frame->pts == AV_NOPTS_VALUE ? -1 : frame->pts * av_q2d(inlink->time_base),
 193                w, h, x, y);
 194     }
 195
 196     return ff_filter_frame(inlink->dst->outputs[0], frame);
 197 }
 198
 199 static const AVFilterPad avfilter_vf_cropdetect_inputs[] = {
 200     {
 201         .name             = "default",
 202         .type             = AVMEDIA_TYPE_VIDEO,
 203         .config_props     = config_input,
 204         .get_video_buffer = ff_null_get_video_buffer,
 205         .filter_frame     = filter_frame,
 206     },
 207     { NULL }
 208 };
 209
 210 static const AVFilterPad avfilter_vf_cropdetect_outputs[] = {
 211     {
 212         .name = "default",
 213         .type = AVMEDIA_TYPE_VIDEO
 214     },
 215     { NULL }
 216 };
 217
 218 AVFilter avfilter_vf_cropdetect = {
 219     .name        = "cropdetect",
 220     .description = NULL_IF_CONFIG_SMALL("Auto-detect crop size."),
 221
 222     .priv_size = sizeof(CropDetectContext),
 223     .init      = init,
 224
 225     .query_formats = query_formats,
 226
 227     .inputs    = avfilter_vf_cropdetect_inputs,
 228
 229     .outputs   = avfilter_vf_cropdetect_outputs,
 230 };